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awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 6, 2025
There is a potential deadlock if we do report zones in an IO context, detailed
in below lockdep report. When one process do a report zones and another process
freezes the block device, the report zones side cannot allocate a tag because
the freeze is already started. This can thus result in new block group creation
to hang forever, blocking the write path.

Thankfully, a new block group should be created on empty zones. So, reporting
the zones is not necessary and we can set the write pointer = 0 and load the
zone capacity from the block layer using bdev_zone_capacity() helper.

 ======================================================
 WARNING: possible circular locking dependency detected
 6.14.0-rc1 #252 Not tainted
 ------------------------------------------------------
 modprobe/1110 is trying to acquire lock:
 ffff888100ac83e0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: __flush_work+0x38f/0xb60

 but task is already holding lock:
 ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130

 which lock already depends on the new lock.

 the existing dependency chain (in reverse order) is:

 -> jonsmirl#3 (&q->q_usage_counter(queue)#16){++++}-{0:0}:
        blk_queue_enter+0x3d9/0x500
        blk_mq_alloc_request+0x47d/0x8e0
        scsi_execute_cmd+0x14f/0xb80
        sd_zbc_do_report_zones+0x1c1/0x470
        sd_zbc_report_zones+0x362/0xd60
        blkdev_report_zones+0x1b1/0x2e0
        btrfs_get_dev_zones+0x215/0x7e0 [btrfs]
        btrfs_load_block_group_zone_info+0x6d2/0x2c10 [btrfs]
        btrfs_make_block_group+0x36b/0x870 [btrfs]
        btrfs_create_chunk+0x147d/0x2320 [btrfs]
        btrfs_chunk_alloc+0x2ce/0xcf0 [btrfs]
        start_transaction+0xce6/0x1620 [btrfs]
        btrfs_uuid_scan_kthread+0x4ee/0x5b0 [btrfs]
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #2 (&fs_info->dev_replace.rwsem){++++}-{4:4}:
        down_read+0x9b/0x470
        btrfs_map_block+0x2ce/0x2ce0 [btrfs]
        btrfs_submit_chunk+0x2d4/0x16c0 [btrfs]
        btrfs_submit_bbio+0x16/0x30 [btrfs]
        btree_write_cache_pages+0xb5a/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #1 (&fs_info->zoned_meta_io_lock){+.+.}-{4:4}:
        __mutex_lock+0x1aa/0x1360
        btree_write_cache_pages+0x252/0xf90 [btrfs]
        do_writepages+0x17f/0x7b0
        __writeback_single_inode+0x114/0xb00
        writeback_sb_inodes+0x52b/0xe00
        wb_writeback+0x1a7/0x800
        wb_workfn+0x12a/0xbd0
        process_one_work+0x85a/0x1460
        worker_thread+0x5e2/0xfc0
        kthread+0x39d/0x750
        ret_from_fork+0x30/0x70
        ret_from_fork_asm+0x1a/0x30

 -> #0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}:
        __lock_acquire+0x2f52/0x5ea0
        lock_acquire+0x1b1/0x540
        __flush_work+0x3ac/0xb60
        wb_shutdown+0x15b/0x1f0
        bdi_unregister+0x172/0x5b0
        del_gendisk+0x841/0xa20
        sd_remove+0x85/0x130
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        __scsi_remove_device+0x272/0x340
        scsi_forget_host+0xf7/0x170
        scsi_remove_host+0xd2/0x2a0
        sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
        device_release_driver_internal+0x368/0x520
        bus_remove_device+0x1f1/0x3f0
        device_del+0x3bd/0x9c0
        device_unregister+0x13/0xa0
        sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
        scsi_debug_exit+0x17/0x70 [scsi_debug]
        __do_sys_delete_module.isra.0+0x321/0x520
        do_syscall_64+0x93/0x180
        entry_SYSCALL_64_after_hwframe+0x76/0x7e

 other info that might help us debug this:

 Chain exists of:
   (work_completion)(&(&wb->dwork)->work) --> &fs_info->dev_replace.rwsem --> &q->q_usage_counter(queue)#16

  Possible unsafe locking scenario:

        CPU0                    CPU1
        ----                    ----
   lock(&q->q_usage_counter(queue)#16);
                                lock(&fs_info->dev_replace.rwsem);
                                lock(&q->q_usage_counter(queue)#16);
   lock((work_completion)(&(&wb->dwork)->work));

  *** DEADLOCK ***

 5 locks held by modprobe/1110:
  #0: ffff88811f7bc108 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  #1: ffff8881022ee0e0 (&shost->scan_mutex){+.+.}-{4:4}, at: scsi_remove_host+0x20/0x2a0
  #2: ffff88811b4c4378 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0x8f/0x520
  jonsmirl#3: ffff8881205b6f20 (&q->q_usage_counter(queue)#16){++++}-{0:0}, at: sd_remove+0x85/0x130
  #4: ffffffffa3284360 (rcu_read_lock){....}-{1:3}, at: __flush_work+0xda/0xb60

 stack backtrace:
 CPU: 0 UID: 0 PID: 1110 Comm: modprobe Not tainted 6.14.0-rc1 #252
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-3.fc41 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0x6a/0x90
  print_circular_bug.cold+0x1e0/0x274
  check_noncircular+0x306/0x3f0
  ? __pfx_check_noncircular+0x10/0x10
  ? mark_lock+0xf5/0x1650
  ? __pfx_check_irq_usage+0x10/0x10
  ? lockdep_lock+0xca/0x1c0
  ? __pfx_lockdep_lock+0x10/0x10
  __lock_acquire+0x2f52/0x5ea0
  ? __pfx___lock_acquire+0x10/0x10
  ? __pfx_mark_lock+0x10/0x10
  lock_acquire+0x1b1/0x540
  ? __flush_work+0x38f/0xb60
  ? __pfx_lock_acquire+0x10/0x10
  ? __pfx_lock_release+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  ? __flush_work+0x38f/0xb60
  __flush_work+0x3ac/0xb60
  ? __flush_work+0x38f/0xb60
  ? __pfx_mark_lock+0x10/0x10
  ? __pfx___flush_work+0x10/0x10
  ? __pfx_wq_barrier_func+0x10/0x10
  ? __pfx___might_resched+0x10/0x10
  ? mark_held_locks+0x94/0xe0
  wb_shutdown+0x15b/0x1f0
  bdi_unregister+0x172/0x5b0
  ? __pfx_bdi_unregister+0x10/0x10
  ? up_write+0x1ba/0x510
  del_gendisk+0x841/0xa20
  ? __pfx_del_gendisk+0x10/0x10
  ? _raw_spin_unlock_irqrestore+0x35/0x60
  ? __pm_runtime_resume+0x79/0x110
  sd_remove+0x85/0x130
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  __scsi_remove_device+0x272/0x340
  scsi_forget_host+0xf7/0x170
  scsi_remove_host+0xd2/0x2a0
  sdebug_driver_remove+0x52/0x2f0 [scsi_debug]
  ? kernfs_remove_by_name_ns+0xc0/0xf0
  device_release_driver_internal+0x368/0x520
  ? kobject_put+0x5d/0x4a0
  bus_remove_device+0x1f1/0x3f0
  device_del+0x3bd/0x9c0
  ? __pfx_device_del+0x10/0x10
  ? __pfx___mutex_unlock_slowpath+0x10/0x10
  device_unregister+0x13/0xa0
  sdebug_do_remove_host+0x1fb/0x290 [scsi_debug]
  scsi_debug_exit+0x17/0x70 [scsi_debug]
  __do_sys_delete_module.isra.0+0x321/0x520
  ? __pfx___do_sys_delete_module.isra.0+0x10/0x10
  ? __pfx_slab_free_after_rcu_debug+0x10/0x10
  ? kasan_save_stack+0x2c/0x50
  ? kasan_record_aux_stack+0xa3/0xb0
  ? __call_rcu_common.constprop.0+0xc4/0xfb0
  ? kmem_cache_free+0x3a0/0x590
  ? __x64_sys_close+0x78/0xd0
  do_syscall_64+0x93/0x180
  ? lock_is_held_type+0xd5/0x130
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? lockdep_hardirqs_on+0x78/0x100
  ? __call_rcu_common.constprop.0+0x3c0/0xfb0
  ? __pfx___call_rcu_common.constprop.0+0x10/0x10
  ? kmem_cache_free+0x3a0/0x590
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  ? __pfx___x64_sys_openat+0x10/0x10
  ? lockdep_hardirqs_on_prepare+0x16d/0x400
  ? do_syscall_64+0x9f/0x180
  ? lockdep_hardirqs_on+0x78/0x100
  ? do_syscall_64+0x9f/0x180
  entry_SYSCALL_64_after_hwframe+0x76/0x7e
 RIP: 0033:0x7f436712b68b
 RSP: 002b:00007ffe9f1a8658 EFLAGS: 00000206 ORIG_RAX: 00000000000000b0
 RAX: ffffffffffffffda RBX: 00005559b367fd80 RCX: 00007f436712b68b
 RDX: 0000000000000000 RSI: 0000000000000800 RDI: 00005559b367fde8
 RBP: 00007ffe9f1a8680 R08: 1999999999999999 R09: 0000000000000000
 R10: 00007f43671a5fe0 R11: 0000000000000206 R12: 0000000000000000
 R13: 00007ffe9f1a86b0 R14: 0000000000000000 R15: 0000000000000000
  </TASK>

Reported-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
CC: <stable@vger.kernel.org> # 6.13+
Tested-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 20, 2025
…ux/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.15, round jonsmirl#3

 - Avoid use of uninitialized memcache pointer in user_mem_abort()

 - Always set HCR_EL2.xMO bits when running in VHE, allowing interrupts
   to be taken while TGE=0 and fixing an ugly bug on AmpereOne that
   occurs when taking an interrupt while clearing the xMO bits
   (AC03_CPU_36)

 - Prevent VMMs from hiding support for AArch64 at any EL virtualized by
   KVM

 - Save/restore the host value for HCRX_EL2 instead of restoring an
   incorrect fixed value

 - Make host_stage2_set_owner_locked() check that the entire requested
   range is memory rather than just the first page
tytso pushed a commit to tytso/ext4 that referenced this pull request Jul 7, 2025
Currently there is no ISB between __deactivate_cptr_traps() disabling
traps that affect EL2 and fpsimd_lazy_switch_to_host() manipulating
registers potentially affected by CPTR traps.

When NV is not in use, this is safe because the relevant registers are
only accessed when guest_owns_fp_regs() && vcpu_has_sve(vcpu), and this
also implies that SVE traps affecting EL2 have been deactivated prior to
__guest_entry().

When NV is in use, a guest hypervisor may have configured SVE traps for
a nested context, and so it is necessary to have an ISB between
__deactivate_cptr_traps() and fpsimd_lazy_switch_to_host().

Due to the current lack of an ISB, when a guest hypervisor enables SVE
traps in CPTR, the host can take an unexpected SVE trap from within
fpsimd_lazy_switch_to_host(), e.g.

| Unhandled 64-bit el1h sync exception on CPU1, ESR 0x0000000066000000 -- SVE
| CPU: 1 UID: 0 PID: 164 Comm: kvm-vcpu-0 Not tainted 6.15.0-rc4-00138-ga05e0f012c05 jonsmirl#3 PREEMPT
| Hardware name: FVP Base RevC (DT)
| pstate: 604023c9 (nZCv DAIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
| pc : __kvm_vcpu_run+0x6f4/0x844
| lr : __kvm_vcpu_run+0x150/0x844
| sp : ffff800083903a60
| x29: ffff800083903a90 x28: ffff000801f4a300 x27: 0000000000000000
| x26: 0000000000000000 x25: ffff000801f90000 x24: ffff000801f900f0
| x23: ffff800081ff7720 x22: 0002433c807d623f x21: ffff000801f90000
| x20: ffff00087f730730 x19: 0000000000000000 x18: 0000000000000000
| x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000
| x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000000
| x11: 0000000000000000 x10: 0000000000000000 x9 : 0000000000000000
| x8 : 0000000000000000 x7 : 0000000000000000 x6 : ffff000801f90d70
| x5 : 0000000000001000 x4 : ffff8007fd739000 x3 : ffff000801f90000
| x2 : 0000000000000000 x1 : 00000000000003cc x0 : ffff800082f9d000
| Kernel panic - not syncing: Unhandled exception
| CPU: 1 UID: 0 PID: 164 Comm: kvm-vcpu-0 Not tainted 6.15.0-rc4-00138-ga05e0f012c05 jonsmirl#3 PREEMPT
| Hardware name: FVP Base RevC (DT)
| Call trace:
|  show_stack+0x18/0x24 (C)
|  dump_stack_lvl+0x60/0x80
|  dump_stack+0x18/0x24
|  panic+0x168/0x360
|  __panic_unhandled+0x68/0x74
|  el1h_64_irq_handler+0x0/0x24
|  el1h_64_sync+0x6c/0x70
|  __kvm_vcpu_run+0x6f4/0x844 (P)
|  kvm_arm_vcpu_enter_exit+0x64/0xa0
|  kvm_arch_vcpu_ioctl_run+0x21c/0x870
|  kvm_vcpu_ioctl+0x1a8/0x9d0
|  __arm64_sys_ioctl+0xb4/0xf4
|  invoke_syscall+0x48/0x104
|  el0_svc_common.constprop.0+0x40/0xe0
|  do_el0_svc+0x1c/0x28
|  el0_svc+0x30/0xcc
|  el0t_64_sync_handler+0x10c/0x138
|  el0t_64_sync+0x198/0x19c
| SMP: stopping secondary CPUs
| Kernel Offset: disabled
| CPU features: 0x0000,000002c0,02df4fb9,97ee773f
| Memory Limit: none
| ---[ end Kernel panic - not syncing: Unhandled exception ]---

Fix this by adding an ISB between __deactivate_traps() and
fpsimd_lazy_switch_to_host().

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Fuad Tabba <tabba@google.com>
Cc: Marc Zyngier <maz@kernel.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20250617133718.4014181-3-mark.rutland@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
tytso pushed a commit to tytso/ext4 that referenced this pull request Jul 7, 2025
…/kernel/git/kvmarm/kvmarm into HEAD

KVM/arm64 fixes for 6.16, take jonsmirl#3

- Fix another set of FP/SIMD/SVE bugs affecting NV, and plugging some
  missing synchronisation

- A small fix for the irqbypass hook fixes, tightening the check and
  ensuring that we only deal with MSI for both the old and the new
  route entry

- Rework the way the shadow LRs are addressed in a nesting
  configuration, plugging an embarrassing bug as well as simplifying
  the whole process

- Add yet another fix for the dreaded arch_timer_edge_cases selftest
tytso pushed a commit to tytso/ext4 that referenced this pull request Aug 26, 2025
The existing code move the VF NIC to new namespace when NETDEV_REGISTER is
received on netvsc NIC. During deletion of the namespace,
default_device_exit_batch() >> default_device_exit_net() is called. When
netvsc NIC is moved back and registered to the default namespace, it
automatically brings VF NIC back to the default namespace. This will cause
the default_device_exit_net() >> for_each_netdev_safe loop unable to detect
the list end, and hit NULL ptr:

[  231.449420] mana 7870:00:00.0 enP30832s1: Moved VF to namespace with: eth0
[  231.449656] BUG: kernel NULL pointer dereference, address: 0000000000000010
[  231.450246] #PF: supervisor read access in kernel mode
[  231.450579] #PF: error_code(0x0000) - not-present page
[  231.450916] PGD 17b8a8067 P4D 0
[  231.451163] Oops: Oops: 0000 [jonsmirl#1] SMP NOPTI
[  231.451450] CPU: 82 UID: 0 PID: 1394 Comm: kworker/u768:1 Not tainted 6.16.0-rc4+ jonsmirl#3 VOLUNTARY
[  231.452042] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 11/21/2024
[  231.452692] Workqueue: netns cleanup_net
[  231.452947] RIP: 0010:default_device_exit_batch+0x16c/0x3f0
[  231.453326] Code: c0 0c f5 b3 e8 d5 db fe ff 48 85 c0 74 15 48 c7 c2 f8 fd ca b2 be 10 00 00 00 48 8d 7d c0 e8 7b 77 25 00 49 8b 86 28 01 00 00 <48> 8b 50 10 4c 8b 2a 4c 8d 62 f0 49 83 ed 10 4c 39 e0 0f 84 d6 00
[  231.454294] RSP: 0018:ff75fc7c9bf9fd00 EFLAGS: 00010246
[  231.454610] RAX: 0000000000000000 RBX: 0000000000000002 RCX: 61c8864680b583eb
[  231.455094] RDX: ff1fa9f71462d800 RSI: ff75fc7c9bf9fd38 RDI: 0000000030766564
[  231.455686] RBP: ff75fc7c9bf9fd78 R08: 0000000000000000 R09: 0000000000000000
[  231.456126] R10: 0000000000000001 R11: 0000000000000004 R12: ff1fa9f70088e340
[  231.456621] R13: ff1fa9f70088e340 R14: ffffffffb3f50c20 R15: ff1fa9f7103e6340
[  231.457161] FS:  0000000000000000(0000) GS:ff1faa6783a08000(0000) knlGS:0000000000000000
[  231.457707] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  231.458031] CR2: 0000000000000010 CR3: 0000000179ab2006 CR4: 0000000000b73ef0
[  231.458434] Call Trace:
[  231.458600]  <TASK>
[  231.458777]  ops_undo_list+0x100/0x220
[  231.459015]  cleanup_net+0x1b8/0x300
[  231.459285]  process_one_work+0x184/0x340

To fix it, move the ns change to a workqueue, and take rtnl_lock to avoid
changing the netdev list when default_device_exit_net() is using it.

Cc: stable@vger.kernel.org
Fixes: 4c26280 ("hv_netvsc: Fix VF namespace also in synthetic NIC NETDEV_REGISTER event")
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>
Link: https://patch.msgid.link/1754511711-11188-1-git-send-email-haiyangz@linux.microsoft.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tytso pushed a commit to tytso/ext4 that referenced this pull request Aug 26, 2025
Commit 3c7ac40 ("scsi: ufs: core: Delegate the interrupt service
routine to a threaded IRQ handler") introduced an IRQ lock inversion
issue. Fix this lock inversion by changing the spin_lock_irq() calls into
spin_lock_irqsave() calls in code that can be called either from
interrupt context or from thread context. This patch fixes the following
lockdep complaint:

WARNING: possible irq lock inversion dependency detected
6.12.30-android16-5-maybe-dirty-4k jonsmirl#1 Tainted: G        W  OE
--------------------------------------------------------
kworker/u28:0/12 just changed the state of lock:
ffffff881e29dd60 (&hba->clk_gating.lock){-...}-{2:2}, at: ufshcd_release_scsi_cmd+0x60/0x110
but this lock took another, HARDIRQ-unsafe lock in the past:
 (shost->host_lock){+.+.}-{2:2}

and interrupts could create inverse lock ordering between them.

other info that might help us debug this:
 Possible interrupt unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(shost->host_lock);
                               local_irq_disable();
                               lock(&hba->clk_gating.lock);
                               lock(shost->host_lock);
  <Interrupt>
    lock(&hba->clk_gating.lock);

 *** DEADLOCK ***

4 locks held by kworker/u28:0/12:
 #0: ffffff8800ac6158 ((wq_completion)async){+.+.}-{0:0}, at: process_one_work+0x1bc/0x65c
 jonsmirl#1: ffffffc085c93d70 ((work_completion)(&entry->work)){+.+.}-{0:0}, at: process_one_work+0x1e4/0x65c
 jonsmirl#2: ffffff881e29c0e0 (&shost->scan_mutex){+.+.}-{3:3}, at: __scsi_add_device+0x74/0x120
 jonsmirl#3: ffffff881960ea00 (&hwq->cq_lock){-...}-{2:2}, at: ufshcd_mcq_poll_cqe_lock+0x28/0x104

the shortest dependencies between 2nd lock and 1st lock:
 -> (shost->host_lock){+.+.}-{2:2} {
    HARDIRQ-ON-W at:
                      lock_acquire+0x134/0x2b4
                      _raw_spin_lock+0x48/0x64
                      ufshcd_sl_intr+0x4c/0xa08
                      ufshcd_threaded_intr+0x70/0x12c
                      irq_thread_fn+0x48/0xa8
                      irq_thread+0x130/0x1ec
                      kthread+0x110/0x134
                      ret_from_fork+0x10/0x20
    SOFTIRQ-ON-W at:
                      lock_acquire+0x134/0x2b4
                      _raw_spin_lock+0x48/0x64
                      ufshcd_sl_intr+0x4c/0xa08
                      ufshcd_threaded_intr+0x70/0x12c
                      irq_thread_fn+0x48/0xa8
                      irq_thread+0x130/0x1ec
                      kthread+0x110/0x134
                      ret_from_fork+0x10/0x20
    INITIAL USE at:
                     lock_acquire+0x134/0x2b4
                     _raw_spin_lock+0x48/0x64
                     ufshcd_sl_intr+0x4c/0xa08
                     ufshcd_threaded_intr+0x70/0x12c
                     irq_thread_fn+0x48/0xa8
                     irq_thread+0x130/0x1ec
                     kthread+0x110/0x134
                     ret_from_fork+0x10/0x20
  }
  ... key      at: [<ffffffc085ba1a98>] scsi_host_alloc.__key+0x0/0x10
  ... acquired at:
   _raw_spin_lock_irqsave+0x5c/0x80
   __ufshcd_release+0x78/0x118
   ufshcd_send_uic_cmd+0xe4/0x118
   ufshcd_dme_set_attr+0x88/0x1c8
   ufs_google_phy_initialization+0x68/0x418 [ufs]
   ufs_google_link_startup_notify+0x78/0x27c [ufs]
   ufshcd_link_startup+0x84/0x720
   ufshcd_init+0xf3c/0x1330
   ufshcd_pltfrm_init+0x728/0x7d8
   ufs_google_probe+0x30/0x84 [ufs]
   platform_probe+0xa0/0xe0
   really_probe+0x114/0x454
   __driver_probe_device+0xa4/0x160
   driver_probe_device+0x44/0x23c
   __driver_attach_async_helper+0x60/0xd4
   async_run_entry_fn+0x4c/0x17c
   process_one_work+0x26c/0x65c
   worker_thread+0x33c/0x498
   kthread+0x110/0x134
   ret_from_fork+0x10/0x20

-> (&hba->clk_gating.lock){-...}-{2:2} {
   IN-HARDIRQ-W at:
                    lock_acquire+0x134/0x2b4
                    _raw_spin_lock_irqsave+0x5c/0x80
                    ufshcd_release_scsi_cmd+0x60/0x110
                    ufshcd_compl_one_cqe+0x2c0/0x3f4
                    ufshcd_mcq_poll_cqe_lock+0xb0/0x104
                    ufs_google_mcq_intr+0x80/0xa0 [ufs]
                    __handle_irq_event_percpu+0x104/0x32c
                    handle_irq_event+0x40/0x9c
                    handle_fasteoi_irq+0x170/0x2e8
                    generic_handle_domain_irq+0x58/0x80
                    gic_handle_irq+0x48/0x104
                    call_on_irq_stack+0x3c/0x50
                    do_interrupt_handler+0x7c/0xd8
                    el1_interrupt+0x34/0x58
                    el1h_64_irq_handler+0x18/0x24
                    el1h_64_irq+0x68/0x6c
                    _raw_spin_unlock_irqrestore+0x3c/0x6c
                    debug_object_assert_init+0x16c/0x21c
                    __mod_timer+0x4c/0x48c
                    schedule_timeout+0xd4/0x16c
                    io_schedule_timeout+0x48/0x70
                    do_wait_for_common+0x100/0x194
                    wait_for_completion_io_timeout+0x48/0x6c
                    blk_execute_rq+0x124/0x17c
                    scsi_execute_cmd+0x18c/0x3f8
                    scsi_probe_and_add_lun+0x204/0xd74
                    __scsi_add_device+0xbc/0x120
                    ufshcd_async_scan+0x80/0x3c0
                    async_run_entry_fn+0x4c/0x17c
                    process_one_work+0x26c/0x65c
                    worker_thread+0x33c/0x498
                    kthread+0x110/0x134
                    ret_from_fork+0x10/0x20
   INITIAL USE at:
                   lock_acquire+0x134/0x2b4
                   _raw_spin_lock_irqsave+0x5c/0x80
                   ufshcd_hold+0x34/0x14c
                   ufshcd_send_uic_cmd+0x28/0x118
                   ufshcd_dme_set_attr+0x88/0x1c8
                   ufs_google_phy_initialization+0x68/0x418 [ufs]
                   ufs_google_link_startup_notify+0x78/0x27c [ufs]
                   ufshcd_link_startup+0x84/0x720
                   ufshcd_init+0xf3c/0x1330
                   ufshcd_pltfrm_init+0x728/0x7d8
                   ufs_google_probe+0x30/0x84 [ufs]
                   platform_probe+0xa0/0xe0
                   really_probe+0x114/0x454
                   __driver_probe_device+0xa4/0x160
                   driver_probe_device+0x44/0x23c
                   __driver_attach_async_helper+0x60/0xd4
                   async_run_entry_fn+0x4c/0x17c
                   process_one_work+0x26c/0x65c
                   worker_thread+0x33c/0x498
                   kthread+0x110/0x134
                   ret_from_fork+0x10/0x20
 }
 ... key      at: [<ffffffc085ba6fe8>] ufshcd_init.__key+0x0/0x10
 ... acquired at:
   mark_lock+0x1c4/0x224
   __lock_acquire+0x438/0x2e1c
   lock_acquire+0x134/0x2b4
   _raw_spin_lock_irqsave+0x5c/0x80
   ufshcd_release_scsi_cmd+0x60/0x110
   ufshcd_compl_one_cqe+0x2c0/0x3f4
   ufshcd_mcq_poll_cqe_lock+0xb0/0x104
   ufs_google_mcq_intr+0x80/0xa0 [ufs]
   __handle_irq_event_percpu+0x104/0x32c
   handle_irq_event+0x40/0x9c
   handle_fasteoi_irq+0x170/0x2e8
   generic_handle_domain_irq+0x58/0x80
   gic_handle_irq+0x48/0x104
   call_on_irq_stack+0x3c/0x50
   do_interrupt_handler+0x7c/0xd8
   el1_interrupt+0x34/0x58
   el1h_64_irq_handler+0x18/0x24
   el1h_64_irq+0x68/0x6c
   _raw_spin_unlock_irqrestore+0x3c/0x6c
   debug_object_assert_init+0x16c/0x21c
   __mod_timer+0x4c/0x48c
   schedule_timeout+0xd4/0x16c
   io_schedule_timeout+0x48/0x70
   do_wait_for_common+0x100/0x194
   wait_for_completion_io_timeout+0x48/0x6c
   blk_execute_rq+0x124/0x17c
   scsi_execute_cmd+0x18c/0x3f8
   scsi_probe_and_add_lun+0x204/0xd74
   __scsi_add_device+0xbc/0x120
   ufshcd_async_scan+0x80/0x3c0
   async_run_entry_fn+0x4c/0x17c
   process_one_work+0x26c/0x65c
   worker_thread+0x33c/0x498
   kthread+0x110/0x134
   ret_from_fork+0x10/0x20

stack backtrace:
CPU: 6 UID: 0 PID: 12 Comm: kworker/u28:0 Tainted: G        W  OE      6.12.30-android16-5-maybe-dirty-4k jonsmirl#1 ccd4020fe444bdf629efc3b86df6be920b8df7d0
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Hardware name: Spacecraft board based on MALIBU (DT)
Workqueue: async async_run_entry_fn
Call trace:
 dump_backtrace+0xfc/0x17c
 show_stack+0x18/0x28
 dump_stack_lvl+0x40/0xa0
 dump_stack+0x18/0x24
 print_irq_inversion_bug+0x2fc/0x304
 mark_lock_irq+0x388/0x4fc
 mark_lock+0x1c4/0x224
 __lock_acquire+0x438/0x2e1c
 lock_acquire+0x134/0x2b4
 _raw_spin_lock_irqsave+0x5c/0x80
 ufshcd_release_scsi_cmd+0x60/0x110
 ufshcd_compl_one_cqe+0x2c0/0x3f4
 ufshcd_mcq_poll_cqe_lock+0xb0/0x104
 ufs_google_mcq_intr+0x80/0xa0 [ufs dd6f385554e109da094ab91d5f7be18625a2222a]
 __handle_irq_event_percpu+0x104/0x32c
 handle_irq_event+0x40/0x9c
 handle_fasteoi_irq+0x170/0x2e8
 generic_handle_domain_irq+0x58/0x80
 gic_handle_irq+0x48/0x104
 call_on_irq_stack+0x3c/0x50
 do_interrupt_handler+0x7c/0xd8
 el1_interrupt+0x34/0x58
 el1h_64_irq_handler+0x18/0x24
 el1h_64_irq+0x68/0x6c
 _raw_spin_unlock_irqrestore+0x3c/0x6c
 debug_object_assert_init+0x16c/0x21c
 __mod_timer+0x4c/0x48c
 schedule_timeout+0xd4/0x16c
 io_schedule_timeout+0x48/0x70
 do_wait_for_common+0x100/0x194
 wait_for_completion_io_timeout+0x48/0x6c
 blk_execute_rq+0x124/0x17c
 scsi_execute_cmd+0x18c/0x3f8
 scsi_probe_and_add_lun+0x204/0xd74
 __scsi_add_device+0xbc/0x120
 ufshcd_async_scan+0x80/0x3c0
 async_run_entry_fn+0x4c/0x17c
 process_one_work+0x26c/0x65c
 worker_thread+0x33c/0x498
 kthread+0x110/0x134
 ret_from_fork+0x10/0x20

Cc: Neil Armstrong <neil.armstrong@linaro.org>
Cc: André Draszik <andre.draszik@linaro.org>
Reviewed-by: Peter Wang <peter.wang@mediatek.com>
Fixes: 3c7ac40 ("scsi: ufs: core: Delegate the interrupt service routine to a threaded IRQ handler")
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20250815155842.472867-2-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
tytso pushed a commit to tytso/ext4 that referenced this pull request Aug 26, 2025
…dlock

When a user creates a dualpi2 qdisc it automatically sets a timer. This
timer will run constantly and update the qdisc's probability field.
The issue is that the timer acquires the qdisc root lock and runs in
hardirq. The qdisc root lock is also acquired in dev.c whenever a packet
arrives for this qdisc. Since the dualpi2 timer callback runs in hardirq,
it may interrupt the packet processing running in softirq. If that happens
and it runs on the same CPU, it will acquire the same lock and cause a
deadlock. The following splat shows up when running a kernel compiled with
lock debugging:

[  +0.000224] WARNING: inconsistent lock state
[  +0.000224] 6.16.0+ #10 Not tainted
[  +0.000169] --------------------------------
[  +0.000029] inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
[  +0.000000] ping/156 [HC0[0]:SC0[2]:HE1:SE0] takes:
[  +0.000000] ffff897841242110 (&sch->root_lock_key){?.-.}-{3:3}, at: __dev_queue_xmit+0x86d/0x1140
[  +0.000000] {IN-HARDIRQ-W} state was registered at:
[  +0.000000]   lock_acquire.part.0+0xb6/0x220
[  +0.000000]   _raw_spin_lock+0x31/0x80
[  +0.000000]   dualpi2_timer+0x6f/0x270
[  +0.000000]   __hrtimer_run_queues+0x1c5/0x360
[  +0.000000]   hrtimer_interrupt+0x115/0x260
[  +0.000000]   __sysvec_apic_timer_interrupt+0x6d/0x1a0
[  +0.000000]   sysvec_apic_timer_interrupt+0x6e/0x80
[  +0.000000]   asm_sysvec_apic_timer_interrupt+0x1a/0x20
[  +0.000000]   pv_native_safe_halt+0xf/0x20
[  +0.000000]   default_idle+0x9/0x10
[  +0.000000]   default_idle_call+0x7e/0x1e0
[  +0.000000]   do_idle+0x1e8/0x250
[  +0.000000]   cpu_startup_entry+0x29/0x30
[  +0.000000]   rest_init+0x151/0x160
[  +0.000000]   start_kernel+0x6f3/0x700
[  +0.000000]   x86_64_start_reservations+0x24/0x30
[  +0.000000]   x86_64_start_kernel+0xc8/0xd0
[  +0.000000]   common_startup_64+0x13e/0x148
[  +0.000000] irq event stamp: 6884
[  +0.000000] hardirqs last  enabled at (6883): [<ffffffffa75700b3>] neigh_resolve_output+0x223/0x270
[  +0.000000] hardirqs last disabled at (6882): [<ffffffffa7570078>] neigh_resolve_output+0x1e8/0x270
[  +0.000000] softirqs last  enabled at (6880): [<ffffffffa757006b>] neigh_resolve_output+0x1db/0x270
[  +0.000000] softirqs last disabled at (6884): [<ffffffffa755b533>] __dev_queue_xmit+0x73/0x1140
[  +0.000000]
              other info that might help us debug this:
[  +0.000000]  Possible unsafe locking scenario:

[  +0.000000]        CPU0
[  +0.000000]        ----
[  +0.000000]   lock(&sch->root_lock_key);
[  +0.000000]   <Interrupt>
[  +0.000000]     lock(&sch->root_lock_key);
[  +0.000000]
               *** DEADLOCK ***

[  +0.000000] 4 locks held by ping/156:
[  +0.000000]  #0: ffff897842332e08 (sk_lock-AF_INET){+.+.}-{0:0}, at: raw_sendmsg+0x41e/0xf40
[  +0.000000]  jonsmirl#1: ffffffffa816f880 (rcu_read_lock){....}-{1:3}, at: ip_output+0x2c/0x190
[  +0.000000]  jonsmirl#2: ffffffffa816f880 (rcu_read_lock){....}-{1:3}, at: ip_finish_output2+0xad/0x950
[  +0.000000]  jonsmirl#3: ffffffffa816f840 (rcu_read_lock_bh){....}-{1:3}, at: __dev_queue_xmit+0x73/0x1140

I am able to reproduce it consistently when running the following:

tc qdisc add dev lo handle 1: root dualpi2
ping -f 127.0.0.1

To fix it, make the timer run in softirq.

Fixes: 320d031 ("sched: Struct definition and parsing of dualpi2 qdisc")
Reviewed-by: Jamal Hadi Salim <jhs@mojatatu.com>
Signed-off-by: Victor Nogueira <victor@mojatatu.com>
Link: https://patch.msgid.link/20250815135317.664993-1-victor@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
tytso pushed a commit to tytso/ext4 that referenced this pull request Aug 26, 2025
In the snd_utimer_create() function, if the kasprintf() function return
NULL, snd_utimer_put_id() will be called, finally use ida_free()
to free the unallocated id 0.

the syzkaller reported the following information:
  ------------[ cut here ]------------
  ida_free called for id=0 which is not allocated.
  WARNING: CPU: 1 PID: 1286 at lib/idr.c:592 ida_free+0x1fd/0x2f0 lib/idr.c:592
  Modules linked in:
  CPU: 1 UID: 0 PID: 1286 Comm: syz-executor164 Not tainted 6.15.8 jonsmirl#3 PREEMPT(lazy)
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-4.fc42 04/01/2014
  RIP: 0010:ida_free+0x1fd/0x2f0 lib/idr.c:592
  Code: f8 fc 41 83 fc 3e 76 69 e8 70 b2 f8 (...)
  RSP: 0018:ffffc900007f79c8 EFLAGS: 00010282
  RAX: 0000000000000000 RBX: 1ffff920000fef3b RCX: ffffffff872176a5
  RDX: ffff88800369d200 RSI: 0000000000000000 RDI: ffff88800369d200
  RBP: 0000000000000000 R08: ffffffff87ba60a5 R09: 0000000000000000
  R10: 0000000000000001 R11: 0000000000000000 R12: 0000000000000000
  R13: 0000000000000002 R14: 0000000000000000 R15: 0000000000000000
  FS:  00007f6f1abc1740(0000) GS:ffff8880d76a0000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
  CR2: 00007f6f1ad7a784 CR3: 000000007a6e2000 CR4: 00000000000006f0
  Call Trace:
   <TASK>
   snd_utimer_put_id sound/core/timer.c:2043 [inline] [snd_timer]
   snd_utimer_create+0x59b/0x6a0 sound/core/timer.c:2184 [snd_timer]
   snd_utimer_ioctl_create sound/core/timer.c:2202 [inline] [snd_timer]
   __snd_timer_user_ioctl.isra.0+0x724/0x1340 sound/core/timer.c:2287 [snd_timer]
   snd_timer_user_ioctl+0x75/0xc0 sound/core/timer.c:2298 [snd_timer]
   vfs_ioctl fs/ioctl.c:51 [inline]
   __do_sys_ioctl fs/ioctl.c:907 [inline]
   __se_sys_ioctl fs/ioctl.c:893 [inline]
   __x64_sys_ioctl+0x198/0x200 fs/ioctl.c:893
   do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
   do_syscall_64+0x7b/0x160 arch/x86/entry/syscall_64.c:94
   entry_SYSCALL_64_after_hwframe+0x76/0x7e
  [...]

The utimer->id should be set properly before the kasprintf() function,
ensures the snd_utimer_put_id() function will free the allocated id.

Fixes: 3774591 ("ALSA: timer: Introduce virtual userspace-driven timers")
Signed-off-by: Dewei Meng <mengdewei@cqsoftware.com.cn>
Link: https://patch.msgid.link/20250821014317.40786-1-mengdewei@cqsoftware.com.cn
Signed-off-by: Takashi Iwai <tiwai@suse.de>
tytso pushed a commit to tytso/ext4 that referenced this pull request Sep 26, 2025
The QuickI2C ACPI _DSD methods return ICRS and ISUB data with a
trailing byte, making the actual length is one more byte than the
structs defined.

It caused stack-out-of-bounds and kernel crash:

kernel: BUG: KASAN: stack-out-of-bounds in quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel: Write of size 12 at addr ffff888106d1f900 by task kworker/u33:2/75
kernel:
kernel: CPU: 3 UID: 0 PID: 75 Comm: kworker/u33:2 Not tainted 6.16.0+ jonsmirl#3 PREEMPT(voluntary)
kernel: Workqueue: async async_run_entry_fn
kernel: Call Trace:
kernel:  <TASK>
kernel:  dump_stack_lvl+0x76/0xa0
kernel:  print_report+0xd1/0x660
kernel:  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
kernel:  ? __kasan_slab_free+0x5d/0x80
kernel:  ? kasan_addr_to_slab+0xd/0xb0
kernel:  kasan_report+0xe1/0x120
kernel:  ? quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  ? quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  kasan_check_range+0x11c/0x200
kernel:  __asan_memcpy+0x3b/0x80
kernel:  quicki2c_acpi_get_dsd_property.constprop.0+0x111/0x1b0 [intel_quicki2c]
kernel:  ? __pfx_quicki2c_acpi_get_dsd_property.constprop.0+0x10/0x10 [intel_quicki2c]
kernel:  quicki2c_get_acpi_resources+0x237/0x730 [intel_quicki2c]
[...]
kernel:  </TASK>
kernel:
kernel: The buggy address belongs to stack of task kworker/u33:2/75
kernel:  and is located at offset 48 in frame:
kernel:  quicki2c_get_acpi_resources+0x0/0x730 [intel_quicki2c]
kernel:
kernel: This frame has 3 objects:
kernel:  [32, 36) 'hid_desc_addr'
kernel:  [48, 59) 'i2c_param'
kernel:  [80, 224) 'i2c_config'

ACPI DSD methods return:

\_SB.PC00.THC0.ICRS Buffer       000000003fdc947b 001 Len 0C = 0A 00 80 1A 06 00 00 00 00 00 00 00
\_SB.PC00.THC0.ISUB Buffer       00000000f2fcbdc4 001 Len 91 = 00 00 00 00 00 00 00 00 00 00 00 00

Adding reserved padding to quicki2c_subip_acpi_parameter/config.

Fixes: 5282e45 ("HID: intel-thc-hid: intel-quicki2c: Add THC QuickI2C ACPI interfaces")
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Reviewed-by: Even Xu <even.xu@intel.com>
Tested-by: Even Xu <even.xu@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
tytso pushed a commit to tytso/ext4 that referenced this pull request Sep 26, 2025
…C regs save

Improper use of secondary pointer (&dev->i2c_subip_regs) caused
kernel crash and out-of-bounds error:

 BUG: KASAN: slab-out-of-bounds in _regmap_bulk_read+0x449/0x510
 Write of size 4 at addr ffff888136005dc0 by task kworker/u33:5/5107

 CPU: 3 UID: 0 PID: 5107 Comm: kworker/u33:5 Not tainted 6.16.0+ jonsmirl#3 PREEMPT(voluntary)
 Workqueue: async async_run_entry_fn
 Call Trace:
  <TASK>
  dump_stack_lvl+0x76/0xa0
  print_report+0xd1/0x660
  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
  ? kasan_complete_mode_report_info+0x26/0x200
  kasan_report+0xe1/0x120
  ? _regmap_bulk_read+0x449/0x510
  ? _regmap_bulk_read+0x449/0x510
  __asan_report_store4_noabort+0x17/0x30
  _regmap_bulk_read+0x449/0x510
  ? __pfx__regmap_bulk_read+0x10/0x10
  regmap_bulk_read+0x270/0x3d0
  pio_complete+0x1ee/0x2c0 [intel_thc]
  ? __pfx_pio_complete+0x10/0x10 [intel_thc]
  ? __pfx_pio_wait+0x10/0x10 [intel_thc]
  ? regmap_update_bits_base+0x13b/0x1f0
  thc_i2c_subip_pio_read+0x117/0x270 [intel_thc]
  thc_i2c_subip_regs_save+0xc2/0x140 [intel_thc]
  ? __pfx_thc_i2c_subip_regs_save+0x10/0x10 [intel_thc]
[...]
 The buggy address belongs to the object at ffff888136005d00
  which belongs to the cache kmalloc-rnd-12-192 of size 192
 The buggy address is located 0 bytes to the right of
  allocated 192-byte region [ffff888136005d00, ffff888136005dc0)

Replaced with direct array indexing (&dev->i2c_subip_regs[i]) to ensure
safe memory access.

Fixes: 4228966 ("HID: intel-thc-hid: intel-thc: Add THC I2C config interfaces")
Signed-off-by: Aaron Ma <aaron.ma@canonical.com>
Reviewed-by: Even Xu <even.xu@intel.com>
Tested-by: Even Xu <even.xu@intel.com>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
tytso pushed a commit to tytso/ext4 that referenced this pull request Sep 26, 2025
A malicious HID device can trigger a slab out-of-bounds during
mt_report_fixup() by passing in report descriptor smaller than
607 bytes. mt_report_fixup() attempts to patch byte offset 607
of the descriptor with 0x25 by first checking if byte offset
607 is 0x15 however it lacks bounds checks to verify if the
descriptor is big enough before conducting this check. Fix
this bug by ensuring the descriptor size is at least 608
bytes before accessing it.

Below is the KASAN splat after the out of bounds access happens:

[   13.671954] ==================================================================
[   13.672667] BUG: KASAN: slab-out-of-bounds in mt_report_fixup+0x103/0x110
[   13.673297] Read of size 1 at addr ffff888103df39df by task kworker/0:1/10
[   13.673297]
[   13.673297] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Not tainted 6.15.0-00005-gec5d573d83f4-dirty jonsmirl#3
[   13.673297] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.2-debian-1.16.2-1 04/04
[   13.673297] Call Trace:
[   13.673297]  <TASK>
[   13.673297]  dump_stack_lvl+0x5f/0x80
[   13.673297]  print_report+0xd1/0x660
[   13.673297]  kasan_report+0xe5/0x120
[   13.673297]  __asan_report_load1_noabort+0x18/0x20
[   13.673297]  mt_report_fixup+0x103/0x110
[   13.673297]  hid_open_report+0x1ef/0x810
[   13.673297]  mt_probe+0x422/0x960
[   13.673297]  hid_device_probe+0x2e2/0x6f0
[   13.673297]  really_probe+0x1c6/0x6b0
[   13.673297]  __driver_probe_device+0x24f/0x310
[   13.673297]  driver_probe_device+0x4e/0x220
[   13.673297]  __device_attach_driver+0x169/0x320
[   13.673297]  bus_for_each_drv+0x11d/0x1b0
[   13.673297]  __device_attach+0x1b8/0x3e0
[   13.673297]  device_initial_probe+0x12/0x20
[   13.673297]  bus_probe_device+0x13d/0x180
[   13.673297]  device_add+0xe3a/0x1670
[   13.673297]  hid_add_device+0x31d/0xa40
[...]

Fixes: c8000de ("HID: multitouch: Add support for GT7868Q")
Cc: stable@vger.kernel.org
Signed-off-by: Qasim Ijaz <qasdev00@gmail.com>
Reviewed-by: Jiri Slaby <jirislaby@kernel.org>
Signed-off-by: Jiri Kosina <jkosina@suse.com>
tytso pushed a commit to tytso/ext4 that referenced this pull request Sep 26, 2025
When a large VM, specifically one that holds a significant number of PTEs,
gets abruptly destroyed, the following warning is seen during the
page-table walk:

 sched: CPU 0 need_resched set for > 100018840 ns (100 ticks) without schedule
 CPU: 0 UID: 0 PID: 9617 Comm: kvm_page_table_ Tainted: G O 6.16.0-smp-DEV jonsmirl#3 NONE
 Tainted: [O]=OOT_MODULE
 Call trace:
  show_stack+0x20/0x38 (C)
  dump_stack_lvl+0x3c/0xb8
  dump_stack+0x18/0x30
  resched_latency_warn+0x7c/0x88
  sched_tick+0x1c4/0x268
  update_process_times+0xa8/0xd8
  tick_nohz_handler+0xc8/0x168
  __hrtimer_run_queues+0x11c/0x338
  hrtimer_interrupt+0x104/0x308
  arch_timer_handler_phys+0x40/0x58
  handle_percpu_devid_irq+0x8c/0x1b0
  generic_handle_domain_irq+0x48/0x78
  gic_handle_irq+0x1b8/0x408
  call_on_irq_stack+0x24/0x30
  do_interrupt_handler+0x54/0x78
  el1_interrupt+0x44/0x88
  el1h_64_irq_handler+0x18/0x28
  el1h_64_irq+0x84/0x88
  stage2_free_walker+0x30/0xa0 (P)
  __kvm_pgtable_walk+0x11c/0x258
  __kvm_pgtable_walk+0x180/0x258
  __kvm_pgtable_walk+0x180/0x258
  __kvm_pgtable_walk+0x180/0x258
  kvm_pgtable_walk+0xc4/0x140
  kvm_pgtable_stage2_destroy+0x5c/0xf0
  kvm_free_stage2_pgd+0x6c/0xe8
  kvm_uninit_stage2_mmu+0x24/0x48
  kvm_arch_flush_shadow_all+0x80/0xa0
  kvm_mmu_notifier_release+0x38/0x78
  __mmu_notifier_release+0x15c/0x250
  exit_mmap+0x68/0x400
  __mmput+0x38/0x1c8
  mmput+0x30/0x68
  exit_mm+0xd4/0x198
  do_exit+0x1a4/0xb00
  do_group_exit+0x8c/0x120
  get_signal+0x6d4/0x778
  do_signal+0x90/0x718
  do_notify_resume+0x70/0x170
  el0_svc+0x74/0xd8
  el0t_64_sync_handler+0x60/0xc8
  el0t_64_sync+0x1b0/0x1b8

The warning is seen majorly on the host kernels that are configured
not to force-preempt, such as CONFIG_PREEMPT_NONE=y. To avoid this,
instead of walking the entire page-table in one go, split it into
smaller ranges, by checking for cond_resched() between each range.
Since the path is executed during VM destruction, after the
page-table structure is unlinked from the KVM MMU, relying on
cond_resched_rwlock_write() isn't necessary.

Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Suggested-by: Oliver Upton <oliver.upton@linux.dev>
Link: https://lore.kernel.org/r/20250820162242.2624752-3-rananta@google.com
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
tytso pushed a commit to tytso/ext4 that referenced this pull request Sep 26, 2025
These iterations require the read lock, otherwise RCU
lockdep will splat:

=============================
WARNING: suspicious RCU usage
6.17.0-rc3-00014-g31419c045d64 #6 Tainted: G           O
-----------------------------
drivers/base/power/main.c:1333 RCU-list traversed in non-reader section!!

other info that might help us debug this:

rcu_scheduler_active = 2, debug_locks = 1
5 locks held by rtcwake/547:
 #0: 00000000643ab418 (sb_writers#6){.+.+}-{0:0}, at: file_start_write+0x2b/0x3a
 jonsmirl#1: 0000000067a0ca88 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x181/0x24b
 jonsmirl#2: 00000000631eac40 (kn->active#3){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x191/0x24b
 jonsmirl#3: 00000000609a1308 (system_transition_mutex){+.+.}-{4:4}, at: pm_suspend+0xaf/0x30b
 #4: 0000000060c0fdb0 (device_links_srcu){.+.+}-{0:0}, at: device_links_read_lock+0x75/0x98

stack backtrace:
CPU: 0 UID: 0 PID: 547 Comm: rtcwake Tainted: G           O        6.17.0-rc3-00014-g31419c045d64 #6 VOLUNTARY
Tainted: [O]=OOT_MODULE
Stack:
 223721b3a80 6089eac6 00000001 00000001
 ffffff00 6089eac6 00000535 6086e528
 721b3ac0 6003c294 00000000 60031fc0
Call Trace:
 [<600407ed>] show_stack+0x10e/0x127
 [<6003c294>] dump_stack_lvl+0x77/0xc6
 [<6003c2fd>] dump_stack+0x1a/0x20
 [<600bc2f8>] lockdep_rcu_suspicious+0x116/0x13e
 [<603d8ea1>] dpm_async_suspend_superior+0x117/0x17e
 [<603d980f>] device_suspend+0x528/0x541
 [<603da24b>] dpm_suspend+0x1a2/0x267
 [<603da837>] dpm_suspend_start+0x5d/0x72
 [<600ca0c9>] suspend_devices_and_enter+0xab/0x736
 [...]

Add the fourth argument to the iteration to annotate
this and avoid the splat.

Fixes: 0679963 ("PM: sleep: Make async suspend handle suppliers like parents")
Fixes: ed18738 ("PM: sleep: Make async resume handle consumers like children")
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Link: https://patch.msgid.link/20250826134348.aba79f6e6299.I9ecf55da46ccf33778f2c018a82e1819d815b348@changeid
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Oct 20, 2025
The ns_bpf_qdisc selftest triggers a kernel panic:

  Oops[#1]:
  CPU 0 Unable to handle kernel paging request at virtual address 0000000000741d58, era == 90000000851b5ac0, ra == 90000000851b5aa4
  CPU: 0 UID: 0 PID: 449 Comm: test_progs Tainted: G           OE       6.16.0+ jonsmirl#3 PREEMPT(full)
  Tainted: [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
  Hardware name: QEMU QEMU Virtual Machine, BIOS unknown 2/2/2022
  pc 90000000851b5ac0 ra 90000000851b5aa4 tp 90000001076b8000 sp 90000001076bb600
  a0 0000000000741ce8 a1 0000000000000001 a2 90000001076bb5c0 a3 0000000000000008
  a4 90000001004c4620 a5 9000000100741ce8 a6 0000000000000000 a7 0100000000000000
  t0 0000000000000010 t1 0000000000000000 t2 9000000104d24d30 t3 0000000000000001
  t4 4f2317da8a7e08c4 t5 fffffefffc002f00 t6 90000001004c4620 t7 ffffffffc61c5b3d
  t8 0000000000000000 u0 0000000000000001 s9 0000000000000050 s0 90000001075bc800
  s1 0000000000000040 s2 900000010597c400 s3 0000000000000008 s4 90000001075bc880
  s5 90000001075bc8f0 s6 0000000000000000 s7 0000000000741ce8 s8 0000000000000000
     ra: 90000000851b5aa4 __qdisc_run+0xac/0x8d8
    ERA: 90000000851b5ac0 __qdisc_run+0xc8/0x8d8
   CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)
   PRMD: 00000004 (PPLV0 +PIE -PWE)
   EUEN: 00000007 (+FPE +SXE +ASXE -BTE)
   ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)
  ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)
   BADV: 0000000000741d58
   PRID: 0014c010 (Loongson-64bit, Loongson-3A5000)
  Modules linked in: bpf_testmod(OE) [last unloaded: bpf_testmod(OE)]
  Process test_progs (pid: 449, threadinfo=000000009af02b3a, task=00000000e9ba4956)
  Stack : 0000000000000000 90000001075bc8ac 90000000869524a8 9000000100741ce8
          90000001075bc800 9000000100415300 90000001075bc8ac 0000000000000000
          900000010597c400 900000008694a000 0000000000000000 9000000105b59000
          90000001075bc800 9000000100741ce8 0000000000000050 900000008513000c
          9000000086936000 0000000100094d4c fffffff400676208 0000000000000000
          9000000105b59000 900000008694a000 9000000086bf0dc0 9000000105b59000
          9000000086bf0d68 9000000085147010 90000001075be788 0000000000000000
          9000000086bf0f98 0000000000000001 0000000000000010 9000000006015840
          0000000000000000 9000000086be6c40 0000000000000000 0000000000000000
          0000000000000000 4f2317da8a7e08c4 0000000000000101 4f2317da8a7e08c4
          ...
  Call Trace:
  [<90000000851b5ac0>] __qdisc_run+0xc8/0x8d8
  [<9000000085130008>] __dev_queue_xmit+0x578/0x10f0
  [<90000000853701c0>] ip6_finish_output2+0x2f0/0x950
  [<9000000085374bc8>] ip6_finish_output+0x2b8/0x448
  [<9000000085370b24>] ip6_xmit+0x304/0x858
  [<90000000853c4438>] inet6_csk_xmit+0x100/0x170
  [<90000000852b32f0>] __tcp_transmit_skb+0x490/0xdd0
  [<90000000852b47fc>] tcp_connect+0xbcc/0x1168
  [<90000000853b9088>] tcp_v6_connect+0x580/0x8a0
  [<90000000852e7738>] __inet_stream_connect+0x170/0x480
  [<90000000852e7a98>] inet_stream_connect+0x50/0x88
  [<90000000850f2814>] __sys_connect+0xe4/0x110
  [<90000000850f2858>] sys_connect+0x18/0x28
  [<9000000085520c94>] do_syscall+0x94/0x1a0
  [<9000000083df1fb8>] handle_syscall+0xb8/0x158

  Code: 4001ad80  2400873f  2400832d <240073cc> 001137ff  001133ff  6407b41f  001503cc  0280041d

  ---[ end trace 0000000000000000 ]---

The bpf_fifo_dequeue prog returns a skb which is a pointer. The pointer
is treated as a 32bit value and sign extend to 64bit in epilogue. This
behavior is right for most bpf prog types but wrong for struct ops which
requires LoongArch ABI.

So let's sign extend struct ops return values according to the LoongArch
ABI ([1]) and return value spec in function model.

[1]: https://loongson.github.io/LoongArch-Documentation/LoongArch-ELF-ABI-EN.html

Cc: stable@vger.kernel.org
Fixes: 6abf17d ("LoongArch: BPF: Add struct ops support for trampoline")
Signed-off-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Oct 20, 2025
Expand the prefault memory selftest to add a regression test for a KVM bug
where KVM's retry logic would result in (breakable) deadlock due to the
memslot deletion waiting on prefaulting to release SRCU, and prefaulting
waiting on the memslot to fully disappear (KVM uses a two-step process to
delete memslots, and KVM x86 retries page faults if a to-be-deleted, a.k.a.
INVALID, memslot is encountered).

To exercise concurrent memslot remove, spawn a second thread to initiate
memslot removal at roughly the same time as prefaulting.  Test memslot
removal for all testcases, i.e. don't limit concurrent removal to only the
success case.  There are essentially three prefault scenarios (so far)
that are of interest:

 1. Success
 2. ENOENT due to no memslot
 3. EAGAIN due to INVALID memslot

For all intents and purposes, #1 and #2 are mutually exclusive, or rather,
easier to test via separate testcases since writing to non-existent memory
is trivial.  But for jonsmirl#3, making it mutually exclusive with #1 _or_ #2 is
actually more complex than testing memslot removal for all scenarios.  The
only requirement to let memslot removal coexist with other scenarios is a
way to guarantee a stable result, e.g. that the "no memslot" test observes
ENOENT, not EAGAIN, for the final checks.

So, rather than make memslot removal mutually exclusive with the ENOENT
scenario, simply restore the memslot and retry prefaulting.  For the "no
memslot" case, KVM_PRE_FAULT_MEMORY should be idempotent, i.e. should
always fail with ENOENT regardless of how many times userspace attempts
prefaulting.

Pass in both the base GPA and the offset (instead of the "full" GPA) so
that the worker can recreate the memslot.

Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20250924174255.2141847-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Oct 20, 2025
Since blamed commit, unregister_netdevice_many_notify() takes the netdev
mutex if the device needs it.

If the device list is too long, this will lock more device mutexes than
lockdep can handle:

unshare -n \
 bash -c 'for i in $(seq 1 100);do ip link add foo$i type dummy;done'

BUG: MAX_LOCK_DEPTH too low!
turning off the locking correctness validator.
depth: 48  max: 48!
48 locks held by kworker/u16:1/69:
 #0: ..148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work
 #1: ..d40 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work
 #2: ..bd0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net
 jonsmirl#3: ..aa8 (rtnl_mutex){+.+.}-{4:4}, at: default_device_exit_batch
 #4: ..cb0 (&dev_instance_lock_key#3){+.+.}-{4:4}, at: unregister_netdevice_many_notify
[..]

Add a helper to close and then unlock a list of net_devices.
Devices that are not up have to be skipped - netif_close_many always
removes them from the list without any other actions taken, so they'd
remain in locked state.

Close devices whenever we've used up half of the tracking slots or we
processed entire list without hitting the limit.

Fixes: 7e4d784 ("net: hold netdev instance lock during rtnetlink operations")
Signed-off-by: Florian Westphal <fw@strlen.de>
Link: https://patch.msgid.link/20251013185052.14021-1-fw@strlen.de
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Oct 28, 2025
The original code causes a circular locking dependency found by lockdep.

======================================================
WARNING: possible circular locking dependency detected
6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 Tainted: G S   U
------------------------------------------------------
xe_fault_inject/5091 is trying to acquire lock:
ffff888156815688 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}, at: __flush_work+0x25d/0x660

but task is already holding lock:

ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #2 (&devcd->mutex){+.+.}-{3:3}:
       mutex_lock_nested+0x4e/0xc0
       devcd_data_write+0x27/0x90
       sysfs_kf_bin_write+0x80/0xf0
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
-> #1 (kn->active#236){++++}-{0:0}:
       kernfs_drain+0x1e2/0x200
       __kernfs_remove+0xae/0x400
       kernfs_remove_by_name_ns+0x5d/0xc0
       remove_files+0x54/0x70
       sysfs_remove_group+0x3d/0xa0
       sysfs_remove_groups+0x2e/0x60
       device_remove_attrs+0xc7/0x100
       device_del+0x15d/0x3b0
       devcd_del+0x19/0x30
       process_one_work+0x22b/0x6f0
       worker_thread+0x1e8/0x3d0
       kthread+0x11c/0x250
       ret_from_fork+0x26c/0x2e0
       ret_from_fork_asm+0x1a/0x30
-> #0 ((work_completion)(&(&devcd->del_wk)->work)){+.+.}-{0:0}:
       __lock_acquire+0x1661/0x2860
       lock_acquire+0xc4/0x2f0
       __flush_work+0x27a/0x660
       flush_delayed_work+0x5d/0xa0
       dev_coredump_put+0x63/0xa0
       xe_driver_devcoredump_fini+0x12/0x20 [xe]
       devm_action_release+0x12/0x30
       release_nodes+0x3a/0x120
       devres_release_all+0x8a/0xd0
       device_unbind_cleanup+0x12/0x80
       device_release_driver_internal+0x23a/0x280
       device_driver_detach+0x14/0x20
       unbind_store+0xaf/0xc0
       drv_attr_store+0x21/0x50
       sysfs_kf_write+0x4a/0x80
       kernfs_fop_write_iter+0x169/0x220
       vfs_write+0x293/0x560
       ksys_write+0x72/0xf0
       __x64_sys_write+0x19/0x30
       x64_sys_call+0x2bf/0x2660
       do_syscall_64+0x93/0xb60
       entry_SYSCALL_64_after_hwframe+0x76/0x7e
other info that might help us debug this:
Chain exists of: (work_completion)(&(&devcd->del_wk)->work) --> kn->active#236 --> &devcd->mutex
 Possible unsafe locking scenario:
       CPU0                    CPU1
       ----                    ----
  lock(&devcd->mutex);
                               lock(kn->active#236);
                               lock(&devcd->mutex);
  lock((work_completion)(&(&devcd->del_wk)->work));
 *** DEADLOCK ***
5 locks held by xe_fault_inject/5091:
 #0: ffff8881129f9488 (sb_writers#5){.+.+}-{0:0}, at: ksys_write+0x72/0xf0
 #1: ffff88810c755078 (&of->mutex#2){+.+.}-{3:3}, at: kernfs_fop_write_iter+0x123/0x220
 #2: ffff8881054811a0 (&dev->mutex){....}-{3:3}, at: device_release_driver_internal+0x55/0x280
 jonsmirl#3: ffff888156815620 (&devcd->mutex){+.+.}-{3:3}, at: dev_coredump_put+0x3f/0xa0
 #4: ffffffff8359e020 (rcu_read_lock){....}-{1:2}, at: __flush_work+0x72/0x660
stack backtrace:
CPU: 14 UID: 0 PID: 5091 Comm: xe_fault_inject Tainted: G S   U              6.16.0-rc6-lgci-xe-xe-pw-151626v3+ #1 PREEMPT_{RT,(lazy)}
Tainted: [S]=CPU_OUT_OF_SPEC, [U]=USER
Hardware name: Micro-Star International Co., Ltd. MS-7D25/PRO Z690-A DDR4(MS-7D25), BIOS 1.10 12/13/2021
Call Trace:
 <TASK>
 dump_stack_lvl+0x91/0xf0
 dump_stack+0x10/0x20
 print_circular_bug+0x285/0x360
 check_noncircular+0x135/0x150
 ? register_lock_class+0x48/0x4a0
 __lock_acquire+0x1661/0x2860
 lock_acquire+0xc4/0x2f0
 ? __flush_work+0x25d/0x660
 ? mark_held_locks+0x46/0x90
 ? __flush_work+0x25d/0x660
 __flush_work+0x27a/0x660
 ? __flush_work+0x25d/0x660
 ? trace_hardirqs_on+0x1e/0xd0
 ? __pfx_wq_barrier_func+0x10/0x10
 flush_delayed_work+0x5d/0xa0
 dev_coredump_put+0x63/0xa0
 xe_driver_devcoredump_fini+0x12/0x20 [xe]
 devm_action_release+0x12/0x30
 release_nodes+0x3a/0x120
 devres_release_all+0x8a/0xd0
 device_unbind_cleanup+0x12/0x80
 device_release_driver_internal+0x23a/0x280
 ? bus_find_device+0xa8/0xe0
 device_driver_detach+0x14/0x20
 unbind_store+0xaf/0xc0
 drv_attr_store+0x21/0x50
 sysfs_kf_write+0x4a/0x80
 kernfs_fop_write_iter+0x169/0x220
 vfs_write+0x293/0x560
 ksys_write+0x72/0xf0
 __x64_sys_write+0x19/0x30
 x64_sys_call+0x2bf/0x2660
 do_syscall_64+0x93/0xb60
 ? __f_unlock_pos+0x15/0x20
 ? __x64_sys_getdents64+0x9b/0x130
 ? __pfx_filldir64+0x10/0x10
 ? do_syscall_64+0x1a2/0xb60
 ? clear_bhb_loop+0x30/0x80
 ? clear_bhb_loop+0x30/0x80
 entry_SYSCALL_64_after_hwframe+0x76/0x7e
RIP: 0033:0x76e292edd574
Code: c7 00 16 00 00 00 b8 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 80 3d d5 ea 0e 00 00 74 13 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 54 c3 0f 1f 00 55 48 89 e5 48 83 ec 20 48 89
RSP: 002b:00007fffe247a828 EFLAGS: 00000202 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 000076e292edd574
RDX: 000000000000000c RSI: 00006267f6306063 RDI: 000000000000000b
RBP: 000000000000000c R08: 000076e292fc4b20 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000202 R12: 00006267f6306063
R13: 000000000000000b R14: 00006267e6859c00 R15: 000076e29322a000
 </TASK>
xe 0000:03:00.0: [drm] Xe device coredump has been deleted.

Fixes: 01daccf ("devcoredump : Serialize devcd_del work")
Cc: Mukesh Ojha <quic_mojha@quicinc.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Danilo Krummrich <dakr@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: stable@vger.kernel.org # v6.1+
Signed-off-by: Maarten Lankhorst <dev@lankhorst.se>
Cc: Matthew Brost <matthew.brost@intel.com>
Acked-by: Mukesh Ojha <mukesh.ojha@oss.qualcomm.com>
Link: https://lore.kernel.org/r/20250723142416.1020423-1-dev@lankhorst.se
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Jan 19, 2026
… to macb_open()

In the non-RT kernel, local_bh_disable() merely disables preemption,
whereas it maps to an actual spin lock in the RT kernel. Consequently,
when attempting to refill RX buffers via netdev_alloc_skb() in
macb_mac_link_up(), a deadlock scenario arises as follows:

   WARNING: possible circular locking dependency detected
   6.18.0-08691-g2061f18ad76e #39 Not tainted
   ------------------------------------------------------
   kworker/0:0/8 is trying to acquire lock:
   ffff00080369bbe0 (&bp->lock){+.+.}-{3:3}, at: macb_start_xmit+0x808/0xb7c

   but task is already holding lock:
   ffff000803698e58 (&queue->tx_ptr_lock){+...}-{3:3}, at: macb_start_xmit
   +0x148/0xb7c

   which lock already depends on the new lock.

   the existing dependency chain (in reverse order) is:

   -> jonsmirl#3 (&queue->tx_ptr_lock){+...}-{3:3}:
          rt_spin_lock+0x50/0x1f0
          macb_start_xmit+0x148/0xb7c
          dev_hard_start_xmit+0x94/0x284
          sch_direct_xmit+0x8c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #2 (_xmit_ETHER#2){+...}-{3:3}:
          rt_spin_lock+0x50/0x1f0
          sch_direct_xmit+0x11c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #1 ((softirq_ctrl.lock)){+.+.}-{3:3}:
          lock_release+0x250/0x348
          __local_bh_enable_ip+0x7c/0x240
          __netdev_alloc_skb+0x1b4/0x1d8
          gem_rx_refill+0xdc/0x240
          gem_init_rings+0xb4/0x108
          macb_mac_link_up+0x9c/0x2b4
          phylink_resolve+0x170/0x614
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   -> #0 (&bp->lock){+.+.}-{3:3}:
          __lock_acquire+0x15a8/0x2084
          lock_acquire+0x1cc/0x350
          rt_spin_lock+0x50/0x1f0
          macb_start_xmit+0x808/0xb7c
          dev_hard_start_xmit+0x94/0x284
          sch_direct_xmit+0x8c/0x37c
          __dev_queue_xmit+0x708/0x1120
          neigh_resolve_output+0x148/0x28c
          ip6_finish_output2+0x2c0/0xb2c
          __ip6_finish_output+0x114/0x308
          ip6_output+0xc4/0x4a4
          mld_sendpack+0x220/0x68c
          mld_ifc_work+0x2a8/0x4f4
          process_one_work+0x20c/0x5f8
          worker_thread+0x1b0/0x35c
          kthread+0x144/0x200
          ret_from_fork+0x10/0x20

   other info that might help us debug this:

   Chain exists of:
     &bp->lock --> _xmit_ETHER#2 --> &queue->tx_ptr_lock

    Possible unsafe locking scenario:

          CPU0                    CPU1
          ----                    ----
     lock(&queue->tx_ptr_lock);
                                  lock(_xmit_ETHER#2);
                                  lock(&queue->tx_ptr_lock);
     lock(&bp->lock);

    *** DEADLOCK ***

   Call trace:
    show_stack+0x18/0x24 (C)
    dump_stack_lvl+0xa0/0xf0
    dump_stack+0x18/0x24
    print_circular_bug+0x28c/0x370
    check_noncircular+0x198/0x1ac
    __lock_acquire+0x15a8/0x2084
    lock_acquire+0x1cc/0x350
    rt_spin_lock+0x50/0x1f0
    macb_start_xmit+0x808/0xb7c
    dev_hard_start_xmit+0x94/0x284
    sch_direct_xmit+0x8c/0x37c
    __dev_queue_xmit+0x708/0x1120
    neigh_resolve_output+0x148/0x28c
    ip6_finish_output2+0x2c0/0xb2c
    __ip6_finish_output+0x114/0x308
    ip6_output+0xc4/0x4a4
    mld_sendpack+0x220/0x68c
    mld_ifc_work+0x2a8/0x4f4
    process_one_work+0x20c/0x5f8
    worker_thread+0x1b0/0x35c
    kthread+0x144/0x200
    ret_from_fork+0x10/0x20

Notably, invoking the mog_init_rings() callback upon link establishment
is unnecessary. Instead, we can exclusively call mog_init_rings() within
the ndo_open() callback. This adjustment resolves the deadlock issue.
Furthermore, since MACB_CAPS_MACB_IS_EMAC cases do not use mog_init_rings()
when opening the network interface via at91ether_open(), moving
mog_init_rings() to macb_open() also eliminates the MACB_CAPS_MACB_IS_EMAC
check.

Fixes: 633e98a ("net: macb: use resolved link config in mac_link_up()")
Cc: stable@vger.kernel.org
Suggested-by: Kevin Hao <kexin.hao@windriver.com>
Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>
Link: https://patch.msgid.link/20251222015624.1994551-1-xiaolei.wang@windriver.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Jan 19, 2026
The GPIO controller is configured as non-sleeping but it uses generic
pinctrl helpers which use a mutex for synchronization.

This can cause the following lockdep splat with shared GPIOs enabled on
boards which have multiple devices using the same GPIO:

BUG: sleeping function called from invalid context at
kernel/locking/mutex.c:591
in_atomic(): 1, irqs_disabled(): 1, non_block: 0, pid: 12, name:
kworker/u16:0
preempt_count: 1, expected: 0
RCU nest depth: 0, expected: 0
6 locks held by kworker/u16:0/12:
  #0: ffff0001f0018d48 ((wq_completion)events_unbound#2){+.+.}-{0:0},
at: process_one_work+0x18c/0x604
  #1: ffff8000842dbdf0 (deferred_probe_work){+.+.}-{0:0}, at:
process_one_work+0x1b4/0x604
  #2: ffff0001f18498f8 (&dev->mutex){....}-{4:4}, at:
__device_attach+0x38/0x1b0
  jonsmirl#3: ffff0001f75f1e90 (&gdev->srcu){.+.?}-{0:0}, at:
gpiod_direction_output_raw_commit+0x0/0x360
  #4: ffff0001f46e3db8 (&shared_desc->spinlock){....}-{3:3}, at:
gpio_shared_proxy_direction_output+0xd0/0x144 [gpio_shared_proxy]
  #5: ffff0001f180ee90 (&gdev->srcu){.+.?}-{0:0}, at:
gpiod_direction_output_raw_commit+0x0/0x360
irq event stamp: 81450
hardirqs last  enabled at (81449): [<ffff8000813acba4>]
_raw_spin_unlock_irqrestore+0x74/0x78
hardirqs last disabled at (81450): [<ffff8000813abfb8>]
_raw_spin_lock_irqsave+0x84/0x88
softirqs last  enabled at (79616): [<ffff8000811455fc>]
__alloc_skb+0x17c/0x1e8
softirqs last disabled at (79614): [<ffff8000811455fc>]
__alloc_skb+0x17c/0x1e8
CPU: 2 UID: 0 PID: 12 Comm: kworker/u16:0 Not tainted
6.19.0-rc4-next-20260105+ #11975 PREEMPT
Hardware name: Hardkernel ODROID-M1 (DT)
Workqueue: events_unbound deferred_probe_work_func
Call trace:
  show_stack+0x18/0x24 (C)
  dump_stack_lvl+0x90/0xd0
  dump_stack+0x18/0x24
  __might_resched+0x144/0x248
  __might_sleep+0x48/0x98
  __mutex_lock+0x5c/0x894
  mutex_lock_nested+0x24/0x30
  pinctrl_get_device_gpio_range+0x44/0x128
  pinctrl_gpio_direction+0x3c/0xe0
  pinctrl_gpio_direction_output+0x14/0x20
  rockchip_gpio_direction_output+0xb8/0x19c
  gpiochip_direction_output+0x38/0x94
  gpiod_direction_output_raw_commit+0x1d8/0x360
  gpiod_direction_output_nonotify+0x7c/0x230
  gpiod_direction_output+0x34/0xf8
  gpio_shared_proxy_direction_output+0xec/0x144 [gpio_shared_proxy]
  gpiochip_direction_output+0x38/0x94
  gpiod_direction_output_raw_commit+0x1d8/0x360
  gpiod_direction_output_nonotify+0x7c/0x230
  gpiod_configure_flags+0xbc/0x480
  gpiod_find_and_request+0x1a0/0x574
  gpiod_get_index+0x58/0x84
  devm_gpiod_get_index+0x20/0xb4
  devm_gpiod_get_optional+0x18/0x30
  rockchip_pcie_probe+0x98/0x380
  platform_probe+0x5c/0xac
  really_probe+0xbc/0x298

Fixes: 936ee26 ("gpio/rockchip: add driver for rockchip gpio")
Cc: stable@vger.kernel.org
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Closes: https://lore.kernel.org/all/d035fc29-3b03-4cd6-b8ec-001f93540bc6@samsung.com/
Acked-by: Heiko Stuebner <heiko@sntech.de>
Link: https://lore.kernel.org/r/20260106090011.21603-1-bartosz.golaszewski@oss.qualcomm.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Jan 19, 2026
…/pub/scm/linux/kernel/git/mkl/linux-can

Marc Kleine-Budde says:

====================
pull-request: can 2026-01-15

this is a pull request of 4 patches for net/main, it super-seeds the
"can 2026-01-14" pull request. The dev refcount leak in patch jonsmirl#3 is
fixed.

The first 3 patches are by Oliver Hartkopp and revert the approach to
instantly reject unsupported CAN frames introduced in
net-next-for-v6.19 and replace it by placing the needed data into the
CAN specific ml_priv.

The last patch is by Tetsuo Handa and fixes a J1939 refcount leak for
j1939_session in session deactivation upon receiving the second RTS.

linux-can-fixes-for-6.19-20260115

* tag 'linux-can-fixes-for-6.19-20260115' of git://git.kernel.org/pub/scm/linux/kernel/git/mkl/linux-can:
  net: can: j1939: j1939_xtp_rx_rts_session_active(): deactivate session upon receiving the second rts
  can: raw: instantly reject disabled CAN frames
  can: propagate CAN device capabilities via ml_priv
  Revert "can: raw: instantly reject unsupported CAN frames"
====================

Link: https://patch.msgid.link/20260115090603.1124860-1-mkl@pengutronix.de
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Mar 25, 2026
…ming

KASAN reports a NULL instruction fetch (RIP=0x0) from
dc_stream_program_cursor_position():

  BUG: kernel NULL pointer dereference, address: 0000000000000000
  RIP: 0010:0x0
  Call Trace:
    dc_stream_program_cursor_position+0x344/0x920 [amdgpu]
    amdgpu_dm_atomic_commit_tail+...

[  +1.041013] BUG: kernel NULL pointer dereference, address: 0000000000000000
[  +0.000027] #PF: supervisor instruction fetch in kernel mode
[  +0.000013] #PF: error_code(0x0010) - not-present page
[  +0.000012] PGD 0 P4D 0
[  +0.000017] Oops: Oops: 0010 [#1] SMP KASAN NOPTI
[  +0.000017] CPU: 0 UID: 0 PID: 10 Comm: kworker/0:1 Tainted: G            E       6.18.0+ jonsmirl#3 PREEMPT(voluntary)
[  +0.000023] Tainted: [E]=UNSIGNED_MODULE
[  +0.000010] Hardware name: ASUS System Product Name/ROG STRIX B550-F GAMING (WI-FI), BIOS 1401 12/03/2020
[  +0.000016] Workqueue: events drm_mode_rmfb_work_fn
[  +0.000022] RIP: 0010:0x0
[  +0.000017] Code: Unable to access opcode bytes at 0xffffffffffffffd6.
[  +0.000015] RSP: 0018:ffffc9000017f4c8 EFLAGS: 00010246
[  +0.000016] RAX: 0000000000000000 RBX: ffff88810afdda80 RCX: 1ffff110457000d1
[  +0.000014] RDX: 1ffffffff87b75bd RSI: 0000000000000000 RDI: ffff88810afdda80
[  +0.000014] RBP: ffffc9000017f538 R08: 0000000000000000 R09: ffff88822b800690
[  +0.000013] R10: 0000000000000000 R11: 0000000000000000 R12: ffffffffc3dbac20
[  +0.000014] R13: 0000000000000000 R14: ffff88811ab80000 R15: dffffc0000000000
[  +0.000014] FS:  0000000000000000(0000) GS:ffff888434599000(0000) knlGS:0000000000000000
[  +0.000015] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  +0.000013] CR2: ffffffffffffffd6 CR3: 000000010ee88000 CR4: 0000000000350ef0
[  +0.000014] Call Trace:
[  +0.000010]  <TASK>
[  +0.000010]  dc_stream_program_cursor_position+0x344/0x920 [amdgpu]
[  +0.001086]  ? __pfx_mutex_lock+0x10/0x10
[  +0.000015]  ? unwind_next_frame+0x18b/0xa70
[  +0.000019]  amdgpu_dm_atomic_commit_tail+0x1124/0xfa20 [amdgpu]
[  +0.001040]  ? ret_from_fork_asm+0x1a/0x30
[  +0.000018]  ? filter_irq_stacks+0x90/0xa0
[  +0.000022]  ? __pfx_amdgpu_dm_atomic_commit_tail+0x10/0x10 [amdgpu]
[  +0.001058]  ? kasan_save_track+0x18/0x70
[  +0.000015]  ? kasan_save_alloc_info+0x37/0x60
[  +0.000015]  ? __kasan_kmalloc+0xc3/0xd0
[  +0.000013]  ? __kmalloc_cache_noprof+0x1aa/0x600
[  +0.000016]  ? drm_atomic_helper_setup_commit+0x788/0x1450
[  +0.000017]  ? drm_atomic_helper_commit+0x7e/0x290
[  +0.000014]  ? drm_atomic_commit+0x205/0x2e0
[  +0.000015]  ? process_one_work+0x629/0xf80
[  +0.000016]  ? worker_thread+0x87f/0x1570
[  +0.000020]  ? srso_return_thunk+0x5/0x5f
[  +0.000014]  ? __kasan_check_write+0x14/0x30
[  +0.000014]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? _raw_spin_lock_irq+0x8a/0xf0
[  +0.000015]  ? __pfx__raw_spin_lock_irq+0x10/0x10
[  +0.000016]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __kasan_check_write+0x14/0x30
[  +0.000014]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __wait_for_common+0x204/0x460
[  +0.000015]  ? sched_clock_noinstr+0x9/0x10
[  +0.000014]  ? __pfx_schedule_timeout+0x10/0x10
[  +0.000014]  ? local_clock_noinstr+0xe/0xd0
[  +0.000015]  ? __pfx___wait_for_common+0x10/0x10
[  +0.000014]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __wait_for_common+0x204/0x460
[  +0.000014]  ? __pfx_schedule_timeout+0x10/0x10
[  +0.000015]  ? __kasan_kmalloc+0xc3/0xd0
[  +0.000015]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? wait_for_completion_timeout+0x1d/0x30
[  +0.000015]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? drm_crtc_commit_wait+0x32/0x180
[  +0.000015]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? drm_atomic_helper_wait_for_dependencies+0x46a/0x800
[  +0.000019]  commit_tail+0x231/0x510
[  +0.000017]  drm_atomic_helper_commit+0x219/0x290
[  +0.000015]  ? __pfx_drm_atomic_helper_commit+0x10/0x10
[  +0.000016]  drm_atomic_commit+0x205/0x2e0
[  +0.000014]  ? __pfx_drm_atomic_commit+0x10/0x10
[  +0.000013]  ? __pfx_drm_connector_free+0x10/0x10
[  +0.000014]  ? __pfx___drm_printfn_info+0x10/0x10
[  +0.000017]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? drm_atomic_set_crtc_for_connector+0x49e/0x660
[  +0.000015]  ? drm_atomic_set_fb_for_plane+0x155/0x290
[  +0.000015]  drm_framebuffer_remove+0xa9b/0x1240
[  +0.000014]  ? finish_task_switch.isra.0+0x15a/0x840
[  +0.000015]  ? __switch_to+0x385/0xda0
[  +0.000015]  ? srso_safe_ret+0x1/0x20
[  +0.000013]  ? __pfx_drm_framebuffer_remove+0x10/0x10
[  +0.000016]  ? kasan_print_address_stack_frame+0x221/0x280
[  +0.000015]  drm_mode_rmfb_work_fn+0x14b/0x240
[  +0.000015]  process_one_work+0x629/0xf80
[  +0.000012]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __kasan_check_write+0x14/0x30
[  +0.000019]  worker_thread+0x87f/0x1570
[  +0.000013]  ? __pfx__raw_spin_lock_irqsave+0x10/0x10
[  +0.000014]  ? __pfx_try_to_wake_up+0x10/0x10
[  +0.000017]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? kasan_print_address_stack_frame+0x227/0x280
[  +0.000017]  ? __pfx_worker_thread+0x10/0x10
[  +0.000014]  kthread+0x396/0x830
[  +0.000013]  ? __pfx__raw_spin_lock_irq+0x10/0x10
[  +0.000015]  ? __pfx_kthread+0x10/0x10
[  +0.000012]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __kasan_check_write+0x14/0x30
[  +0.000014]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? recalc_sigpending+0x180/0x210
[  +0.000015]  ? srso_return_thunk+0x5/0x5f
[  +0.000013]  ? __pfx_kthread+0x10/0x10
[  +0.000014]  ret_from_fork+0x31c/0x3e0
[  +0.000014]  ? __pfx_kthread+0x10/0x10
[  +0.000013]  ret_from_fork_asm+0x1a/0x30
[  +0.000019]  </TASK>
[  +0.000010] Modules linked in: rfcomm(E) cmac(E) algif_hash(E) algif_skcipher(E) af_alg(E) snd_seq_dummy(E) snd_hrtimer(E) qrtr(E) xt_MASQUERADE(E) nf_nat(E) nf_conntrack(E) nf_defrag_ipv6(E) nf_defrag_ipv4(E) xt_mark(E) xt_tcpudp(E) nft_compat(E) nf_tables(E) x_tables(E) bnep(E) snd_hda_codec_alc882(E) snd_hda_codec_atihdmi(E) snd_hda_codec_realtek_lib(E) snd_hda_codec_hdmi(E) snd_hda_codec_generic(E) iwlmvm(E) snd_hda_intel(E) binfmt_misc(E) snd_hda_codec(E) snd_hda_core(E) mac80211(E) snd_intel_dspcfg(E) snd_intel_sdw_acpi(E) snd_hwdep(E) snd_pcm(E) libarc4(E) snd_seq_midi(E) snd_seq_midi_event(E) snd_rawmidi(E) amd_atl(E) intel_rapl_msr(E) snd_seq(E) intel_rapl_common(E) iwlwifi(E) jc42(E) snd_seq_device(E) btusb(E) snd_timer(E) btmtk(E) btrtl(E) edac_mce_amd(E) eeepc_wmi(E) polyval_clmulni(E) btbcm(E) ghash_clmulni_intel(E) asus_wmi(E) ee1004(E) platform_profile(E) btintel(E) snd(E) nls_iso8859_1(E) aesni_intel(E) soundcore(E) i2c_piix4(E) cfg80211(E) sparse_keymap(E) wmi_bmof(E) bluetooth(E) k10temp(E) rapl(E)
[  +0.000300]  i2c_smbus(E) ccp(E) joydev(E) input_leds(E) gpio_amdpt(E) mac_hid(E) sch_fq_codel(E) msr(E) parport_pc(E) ppdev(E) lp(E) parport(E) efi_pstore(E) nfnetlink(E) dmi_sysfs(E) autofs4(E) cdc_ether(E) usbnet(E) amdgpu(E) amdxcp(E) hid_generic(E) i2c_algo_bit(E) drm_ttm_helper(E) ttm(E) drm_exec(E) drm_panel_backlight_quirks(E) gpu_sched(E) drm_suballoc_helper(E) video(E) drm_buddy(E) usbhid(E) drm_display_helper(E) r8152(E) hid(E) mii(E) cec(E) ahci(E) rc_core(E) igc(E) libahci(E) wmi(E)
[  +0.000294] CR2: 0000000000000000
[  +0.000013] ---[ end trace 0000000000000000 ]---

The crash happens when we unconditionally call into the timing generator
manual trigger hook:

  pipe_ctx->stream_res.tg->funcs->program_manual_trigger(...)

On some configurations the timing generator (tg), its funcs table, or the
program_manual_trigger callback can be NULL. Guard all of these before
calling the hook. If the first pipe matching the stream cannot trigger,
keep scanning to find another matching pipe with a valid hook.
The issue was originally found on Vg20/DCE 12.1
Mario successfully tested on Polaris 11/DCE 11.2

Cc: Aurabindo Pillai <aurabindo.pillai@amd.com>
Cc: Alexander Deucher <alexander.deucher@amd.com>
Cc: Christian Koenig  <christian.koenig@amd.com>

Fixes: ba448f9 ("drm/amd/display: mouse event trigger to boost RR when idle")
Suggested-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Reviewed-and-tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Mar 25, 2026
With PREEMPT_RT as potential configuration option, spinlock_t is now
considered as a sleeping lock, and thus might cause issues when used in
an atomic context. But even with PREEMPT_RT as potential configuration
option, raw_spinlock_t remains as a true spinning lock/atomic context.
This creates potential issues with the s390 debug/tracing feature. The
functions to trace errors are called in various contexts, including
under lock of raw_spinlock_t, and thus the used spinlock_t in each debug
area is in violation of the locking semantics.

Here are two examples involving failing PCI Read accesses that are
traced while holding `pci_lock` in `drivers/pci/access.c`:

=============================
[ BUG: Invalid wait context ]
6.19.0-devel #18 Not tainted
-----------------------------
bash/3833 is trying to lock:
0000027790baee30 (&rc->lock){-.-.}-{3:3}, at: debug_event_common+0xfc/0x300
other info that might help us debug this:
context-{5:5}
5 locks held by bash/3833:
 #0: 0000027efbb29450 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x7c/0xf0
 #1: 00000277f0504a90 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x13e/0x260
 #2: 00000277beed8c18 (kn->active#339){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x164/0x260
 jonsmirl#3: 00000277e9859190 (&dev->mutex){....}-{4:4}, at: pci_dev_lock+0x2e/0x40
 #4: 00000383068a7708 (pci_lock){....}-{2:2}, at: pci_bus_read_config_dword+0x4a/0xb0
stack backtrace:
CPU: 6 UID: 0 PID: 3833 Comm: bash Kdump: loaded Not tainted 6.19.0-devel #18 PREEMPTLAZY
Hardware name: IBM 9175 ME1 701 (LPAR)
Call Trace:
 [<00000383048afec2>] dump_stack_lvl+0xa2/0xe8
 [<00000383049ba166>] __lock_acquire+0x816/0x1660
 [<00000383049bb1fa>] lock_acquire+0x24a/0x370
 [<00000383059e3860>] _raw_spin_lock_irqsave+0x70/0xc0
 [<00000383048bbb6c>] debug_event_common+0xfc/0x300
 [<0000038304900b0a>] __zpci_load+0x17a/0x1f0
 [<00000383048fad88>] pci_read+0x88/0xd0
 [<00000383054cbce0>] pci_bus_read_config_dword+0x70/0xb0
 [<00000383054d55e4>] pci_dev_wait+0x174/0x290
 [<00000383054d5a3e>] __pci_reset_function_locked+0xfe/0x170
 [<00000383054d9b30>] pci_reset_function+0xd0/0x100
 [<00000383054ee21a>] reset_store+0x5a/0x80
 [<0000038304e98758>] kernfs_fop_write_iter+0x1e8/0x260
 [<0000038304d995da>] new_sync_write+0x13a/0x180
 [<0000038304d9c5d0>] vfs_write+0x200/0x330
 [<0000038304d9c88c>] ksys_write+0x7c/0xf0
 [<00000383059cfa80>] __do_syscall+0x210/0x500
 [<00000383059e4c06>] system_call+0x6e/0x90
INFO: lockdep is turned off.

=============================
[ BUG: Invalid wait context ]
6.19.0-devel jonsmirl#3 Not tainted
-----------------------------
bash/6861 is trying to lock:
0000009da05c7430 (&rc->lock){-.-.}-{3:3}, at: debug_event_common+0xfc/0x300
other info that might help us debug this:
context-{5:5}
5 locks held by bash/6861:
 #0: 000000acff404450 (sb_writers#3){.+.+}-{0:0}, at: ksys_write+0x7c/0xf0
 #1: 000000acff41c490 (&of->mutex#2){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x13e/0x260
 #2: 0000009da36937d8 (kn->active#75){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x164/0x260
 jonsmirl#3: 0000009dd15250d0 (&zdev->state_lock){+.+.}-{4:4}, at: enable_slot+0x2e/0xc0
 #4: 000001a19682f708 (pci_lock){....}-{2:2}, at: pci_bus_read_config_byte+0x42/0xa0
stack backtrace:
CPU: 16 UID: 0 PID: 6861 Comm: bash Kdump: loaded Not tainted 6.19.0-devel jonsmirl#3 PREEMPTLAZY
Hardware name: IBM 9175 ME1 701 (LPAR)
Call Trace:
 [<000001a194837ec2>] dump_stack_lvl+0xa2/0xe8
 [<000001a194942166>] __lock_acquire+0x816/0x1660
 [<000001a1949431fa>] lock_acquire+0x24a/0x370
 [<000001a19596b810>] _raw_spin_lock_irqsave+0x70/0xc0
 [<000001a194843b6c>] debug_event_common+0xfc/0x300
 [<000001a194888b0a>] __zpci_load+0x17a/0x1f0
 [<000001a194882d88>] pci_read+0x88/0xd0
 [<000001a195453b88>] pci_bus_read_config_byte+0x68/0xa0
 [<000001a195457bc2>] pci_setup_device+0x62/0xad0
 [<000001a195458e70>] pci_scan_single_device+0x90/0xe0
 [<000001a19488a0f6>] zpci_bus_scan_device+0x46/0x80
 [<000001a19547f958>] enable_slot+0x98/0xc0
 [<000001a19547f134>] power_write_file+0xc4/0x110
 [<000001a194e20758>] kernfs_fop_write_iter+0x1e8/0x260
 [<000001a194d215da>] new_sync_write+0x13a/0x180
 [<000001a194d245d0>] vfs_write+0x200/0x330
 [<000001a194d2488c>] ksys_write+0x7c/0xf0
 [<000001a195957a30>] __do_syscall+0x210/0x500
 [<000001a19596cbb6>] system_call+0x6e/0x90
INFO: lockdep is turned off.

Since it is desired to keep it possible to create trace records in most
situations, including this particular case (failing PCI config space
accesses are relevant), convert the used spinlock_t in `struct
debug_info` to raw_spinlock_t.

The impact is small, as the debug area lock only protects bounded memory
access without external dependencies, apart from one function
debug_set_size() where kfree() is implicitly called with the lock held.
Move debug_info_free() out of this lock, to keep remove this external
dependency.

Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Benjamin Block <bblock@linux.ibm.com>
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
When unregistered my self-written scx scheduler, the following panic
occurs.

[  229.923133] Kernel text patching generated an invalid instruction at 0xffff80009bc2c1f8!
[  229.923146] Internal error: Oops - BRK: 00000000f2000100 [#1]  SMP
[  230.077871] CPU: 48 UID: 0 PID: 1760 Comm: kworker/u583:7 Not tainted 7.0.0+ jonsmirl#3 PREEMPT(full)
[  230.086677] Hardware name: NVIDIA GB200 NVL/P3809-BMC, BIOS 02.05.12 20251107
[  230.093972] Workqueue: events_unbound bpf_map_free_deferred
[  230.099675] Sched_ext: invariant_0.1.0_aarch64_unknown_linux_gnu_debug (disabling), task: runnable_at=-174ms
[  230.116843] pc : 0xffff80009bc2c1f8
[  230.120406] lr : dequeue_task_scx+0x270/0x2d0
[  230.217749] Call trace:
[  230.228515]  0xffff80009bc2c1f8 (P)
[  230.232077]  dequeue_task+0x84/0x188
[  230.235728]  sched_change_begin+0x1dc/0x250
[  230.240000]  __set_cpus_allowed_ptr_locked+0x17c/0x240
[  230.245250]  __set_cpus_allowed_ptr+0x74/0xf0
[  230.249701]  ___migrate_enable+0x4c/0xa0
[  230.253707]  bpf_map_free_deferred+0x1a4/0x1b0
[  230.258246]  process_one_work+0x184/0x540
[  230.262342]  worker_thread+0x19c/0x348
[  230.266170]  kthread+0x13c/0x150
[  230.269465]  ret_from_fork+0x10/0x20
[  230.281393] Code: d4202000 d4202000 d4202000 d4202000 (d4202000)
[  230.287621] ---[ end trace 0000000000000000 ]---
[  231.160046] Kernel panic - not syncing: Oops - BRK: Fatal exception in interrupt

The root cause is that the JIT page backing ops->quiescent() is freed
before all callers of that function have stopped.

The expected ordering during teardown is:
    bitmap_zero(sch->has_op) + synchronize_rcu()
        -> guarantees no CPU will ever call sch->ops.* again
    -> only THEN free the BPF struct_ops JIT page

bpf_scx_unreg() is supposed to enforce the order, but after
commit f4a6c50 ("sched_ext: Always bounce scx_disable() through
irq_work"), disable_work is no longer queued directly, causing
kthread_flush_work() to be a noop. Thus, the caller drops the struct_ops
map too early and poisoned with AARCH64_BREAK_FAULT before
disable_workfn ever execute.

So the subsequent dequeue_task() still sees SCX_HAS_OP(sch, quiescent)
as true and calls ops.quiescent, which hit on the poisoned page and BRK
panic.

Add a helper scx_flush_disable_work() so the future use cases that want
to flush disable_work can use it.
Also amend the call for scx_root_enable_workfn() and
scx_sub_enable_workfn() which have similar pattern in the error path.

Fixes: f4a6c50 ("sched_ext: Always bounce scx_disable() through irq_work")
Signed-off-by: Richard Cheng <icheng@nvidia.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Reviewed-by: Cheng-Yang Chou <yphbchou0911@gmail.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
ice_reset_all_vfs() ignores the return value of ice_vf_rebuild_vsi().
When the VSI rebuild fails (e.g. during NVM firmware update via
nvmupdate64e), ice_vsi_rebuild() tears down the VSI on its error path,
leaving txq_map and rxq_map as NULL. The subsequent unconditional call
to ice_vf_post_vsi_rebuild() leads to a NULL pointer dereference in
ice_ena_vf_q_mappings() when it accesses vsi->txq_map[0].

The single-VF reset path in ice_reset_vf() already handles this
correctly by checking the return value of ice_vf_reconfig_vsi() and
skipping ice_vf_post_vsi_rebuild() on failure.

Apply the same pattern to ice_reset_all_vfs(): check the return value
of ice_vf_rebuild_vsi() and skip ice_vf_post_vsi_rebuild() and
ice_eswitch_attach_vf() on failure. The VF is left safely disabled
(ICE_VF_STATE_INIT not set, VFGEN_RSTAT not set to VFACTIVE) and can
be recovered via a VFLR triggered by a PCI reset of the VF
(sysfs reset or driver rebind).

Note that this patch does not prevent the VF VSI rebuild from failing
during NVM update — the underlying cause is firmware being in a
transitional state while the EMP reset is processed, which can cause
Admin Queue commands (ice_add_vsi, ice_cfg_vsi_lan) to fail. This
patch only prevents the subsequent NULL pointer dereference that
crashes the kernel when the rebuild does fail.

 crash> bt
     PID: 50795    TASK: ff34c9ee708dc680  CPU: 1    COMMAND: "kworker/u512:5"
      #0 [ff72159bcfe5bb50] machine_kexec at ffffffffaa8850ee
      #1 [ff72159bcfe5bba8] __crash_kexec at ffffffffaaa15fba
      #2 [ff72159bcfe5bc68] crash_kexec at ffffffffaaa16540
      jonsmirl#3 [ff72159bcfe5bc70] oops_end at ffffffffaa837eda
      #4 [ff72159bcfe5bc90] page_fault_oops at ffffffffaa893997
      #5 [ff72159bcfe5bce8] exc_page_fault at ffffffffab528595
      #6 [ff72159bcfe5bd10] asm_exc_page_fault at ffffffffab600bb2
         [exception RIP: ice_ena_vf_q_mappings+0x79]
         RIP: ffffffffc0a85b29  RSP: ff72159bcfe5bdc8  RFLAGS: 00010206
         RAX: 00000000000f0000  RBX: ff34c9efc9c00000  RCX: 0000000000000000
         RDX: 0000000000000000  RSI: 0000000000000010  RDI: ff34c9efc9c00000
         RBP: ff34c9efc27d4828   R8: 0000000000000093   R9: 0000000000000040
         R10: ff34c9efc27d4828  R11: 0000000000000040  R12: 0000000000100000
         R13: 0000000000000010  R14:   R15:
         ORIG_RAX: ffffffffffffffff  CS: 0010  SS: 0018
      #7 [ff72159bcfe5bdf8] ice_sriov_post_vsi_rebuild at ffffffffc0a85e2e [ice]
      #8 [ff72159bcfe5be08] ice_reset_all_vfs at ffffffffc0a920b4 [ice]
      #9 [ff72159bcfe5be48] ice_service_task at ffffffffc0a31519 [ice]
     #10 [ff72159bcfe5be88] process_one_work at ffffffffaa93dca4
     #11 [ff72159bcfe5bec8] worker_thread at ffffffffaa93e9de
     #12 [ff72159bcfe5bf18] kthread at ffffffffaa946663
     #13 [ff72159bcfe5bf50] ret_from_fork at ffffffffaa8086b9

 The panic occurs attempting to dereference the NULL pointer in RDX at
 ice_sriov.c:294, which loads vsi->txq_map (offset 0x4b8 in ice_vsi).

 The faulting VSI is an allocated slab object but not fully initialized
 after a failed ice_vsi_rebuild():

  crash> struct ice_vsi 0xff34c9efc27d4828
    netdev = 0x0,
    rx_rings = 0x0,
    tx_rings = 0x0,
    q_vectors = 0x0,
    txq_map = 0x0,
    rxq_map = 0x0,
    alloc_txq = 0x10,
    num_txq = 0x10,
    alloc_rxq = 0x10,
    num_rxq = 0x10,

 The nvmupdate64e process was performing NVM firmware update:

  crash> bt 0xff34c9edd1a30000
  PID: 49858    TASK: ff34c9edd1a30000  CPU: 1    COMMAND: "nvmupdate64e"
   #0 [ff72159bcd617618] __schedule at ffffffffab5333f8
   #4 [ff72159bcd617750] ice_sq_send_cmd at ffffffffc0a35347 [ice]
   #5 [ff72159bcd6177a8] ice_sq_send_cmd_retry at ffffffffc0a35b47 [ice]
   #6 [ff72159bcd617810] ice_aq_send_cmd at ffffffffc0a38018 [ice]
   #7 [ff72159bcd617848] ice_aq_read_nvm at ffffffffc0a40254 [ice]
   #8 [ff72159bcd6178b8] ice_read_flat_nvm at ffffffffc0a4034c [ice]
   #9 [ff72159bcd617918] ice_devlink_nvm_snapshot at ffffffffc0a6ffa5 [ice]

 dmesg:
  ice 0000:13:00.0: firmware recommends not updating fw.mgmt, as it
    may result in a downgrade. continuing anyways
  ice 0000:13:00.1: ice_init_nvm failed -5
  ice 0000:13:00.1: Rebuild failed, unload and reload driver

Fixes: 12bb018 ("ice: Refactor VF reset")
Signed-off-by: Petr Oros <poros@redhat.com>
Tested-by: Rafal Romanowski <rafal.romanowski@intel.com>
Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Link: https://patch.msgid.link/20260427-jk-iwl-net-petr-oros-fixes-v1-5-cdcb48303fd8@intel.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
…equeue_peeked

When red qdisc has children (eg qfq qdisc) whose peek() callback is
qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such
qdiscs (eg illustrated in patch jonsmirl#3 as tbf) wants to retrieve an skb from
its child (red in this case), it will do the following:
 1a. do a peek() - and when sensing there's an skb the child can offer, then
     - the child in this case(red) calls its child's (qfq) peek.
        qfq does the right thing and will return the gso_skb queue packet.
        Note: if there wasnt a gso_skb entry then qfq will store it there.
 1b. invoke a dequeue() on the child (red). And herein lies the problem.
     - red will call the child's dequeue() which will essentially just
       try to grab something of qfq's queue.

[   78.667668][  T363] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
[   78.667927][  T363] CPU: 1 UID: 0 PID: 363 Comm: ping Not tainted 7.1.0-rc1-00033-g46f74a3f7d57-dirty #790 PREEMPT(full)
[   78.668263][  T363] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[   78.668486][  T363] RIP: 0010:qfq_dequeue+0x446/0xc90 [sch_qfq]
[   78.668718][  T363] Code: 54 c0 e8 dd 90 00 f1 48 c7 c7 e0 03 54 c0 48 89 de e8 ce 90 00 f1 48 8d 7b 48 b8 ff ff 37 00 48 89 fa 48 c1 e0 2a 48 c1 ea 03 <80> 3c 02 00 74 05 e8 ef a1 e1 f1 48 8b 7b 48 48 8d 54 24 58 48 8d
[   78.669312][  T363] RSP: 0018:ffff88810de573e0 EFLAGS: 00010216
[   78.669533][  T363] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: 0000000000000000
[   78.669790][  T363] RDX: 0000000000000009 RSI: 0000000000000004 RDI: 0000000000000048
[   78.670044][  T363] RBP: ffff888110dc4000 R08: ffffffffb1b0885a R09: fffffbfff6ba9078
[   78.670297][  T363] R10: 0000000000000003 R11: ffff888110e31c80 R12: 0000001880000000
[   78.670560][  T363] R13: ffff888110dc4150 R14: ffff888110dc42b8 R15: 0000000000000200
[   78.670814][  T363] FS:  00007f66a8f09c40(0000) GS:ffff888163428000(0000) knlGS:0000000000000000
[   78.671110][  T363] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[   78.671324][  T363] CR2: 000055db4c6a30a8 CR3: 000000010da67000 CR4: 0000000000750ef0
[   78.671585][  T363] PKRU: 55555554
[   78.671713][  T363] Call Trace:
[   78.671843][  T363]  <TASK>
[   78.671936][  T363]  ? __pfx_qfq_dequeue+0x10/0x10 [sch_qfq]
[   78.672148][  T363]  ? __pfx__printk+0x10/0x10
[   78.672322][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
[   78.672496][  T363]  ? lockdep_hardirqs_on_prepare+0xa8/0x1a0
[   78.672706][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
[   78.672875][  T363]  ? trace_hardirqs_on+0x19/0x1a0
[   78.673047][  T363]  red_dequeue+0x65/0x270 [sch_red]
[   78.673217][  T363]  ? srso_alias_return_thunk+0x5/0xfbef5
[   78.673385][  T363]  tbf_dequeue.cold+0xb0/0x70c [sch_tbf]
[   78.673566][  T363]  __qdisc_run+0x169/0x1900

The right thing to do in #1b is to grab the skb off gso_skb queue.
This patchset fixes that issue by changing #1b to use qdisc_dequeue_peeked()
method instead.

Fixes: 77be155 ("pkt_sched: Add peek emulation for non-work-conserving qdiscs.")
Reported-by: Manas <ghandatmanas@gmail.com>
Reported-by: Rakshit Awasthi <rakshitawasthi17@gmail.com>
Signed-off-by: Jamal Hadi Salim <jhs@mojatatu.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430152957.194015-2-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
…equeue_peeked

When sfb has children (eg qfq qdisc) whose peek() callback is
qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such
qdiscs (eg illustrated in patch jonsmirl#3 as tbf) wants to retrieve an skb from
its child (sfb in this case), it will do the following:
 1a. do a peek() - and when sensing there's an skb the child can offer, then
     - the child in this case(sfb) calls its child's (qfq) peek.
        qfq does the right thing and will return the gso_skb queue packet.
        Note: if there wasnt a gso_skb entry then qfq will store it there.
 1b. invoke a dequeue() on the child (sfb). And herein lies the problem.
     - sfb will call the child's dequeue() which will essentially just
       try to grab something of qfq's queue.

[  127.594489][  T453] KASAN: null-ptr-deref in range [0x0000000000000048-0x000000000000004f]
[  127.594741][  T453] CPU: 2 UID: 0 PID: 453 Comm: ping Not tainted 7.1.0-rc1-00035-gac961974495b-dirty #793 PREEMPT(full)
[  127.595059][  T453] Hardware name: Bochs Bochs, BIOS Bochs 01/01/2011
[  127.595254][  T453] RIP: 0010:qfq_dequeue+0x35c/0x1650 [sch_qfq]
[  127.595461][  T453] Code: 00 fc ff df 80 3c 02 00 0f 85 17 0e 00 00 4c 8d 73 48 48 89 9d b8 02 00 00 48 b8 00 00 00 00 00 fc ff df 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 76 0c 00 00 48 b8 00 00 00 00 00 fc ff df 4c 8b
[  127.596081][  T453] RSP: 0018:ffff88810e5af440 EFLAGS: 00010216
[  127.596337][  T453] RAX: dffffc0000000000 RBX: 0000000000000000 RCX: dffffc0000000000
[  127.596623][  T453] RDX: 0000000000000009 RSI: 0000001880000000 RDI: ffff888104fd82b0
[  127.596917][  T453] RBP: ffff888104fd8000 R08: ffff888104fd8280 R09: 1ffff110211893a3
[  127.597165][  T453] R10: 1ffff110211893a6 R11: 1ffff110211893a7 R12: 0000001880000000
[  127.597404][  T453] R13: ffff888104fd82b8 R14: 0000000000000048 R15: 0000000040000000
[  127.597644][  T453] FS:  00007fc380cbfc40(0000) GS:ffff88816f2a8000(0000) knlGS:0000000000000000
[  127.597956][  T453] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  127.598160][  T453] CR2: 00005610aa9890a8 CR3: 000000010369e000 CR4: 0000000000750ef0
[  127.598390][  T453] PKRU: 55555554
[  127.598509][  T453] Call Trace:
[  127.598629][  T453]  <TASK>
[  127.598718][  T453]  ? mark_held_locks+0x40/0x70
[  127.598890][  T453]  ? srso_alias_return_thunk+0x5/0xfbef5
[  127.599053][  T453]  sfb_dequeue+0x88/0x4d0
[  127.599174][  T453]  ? ktime_get+0x137/0x230
[  127.599328][  T453]  ? srso_alias_return_thunk+0x5/0xfbef5
[  127.599480][  T453]  ? qdisc_peek_dequeued+0x7b/0x350 [sch_qfq]
[  127.599670][  T453]  ? srso_alias_return_thunk+0x5/0xfbef5
[  127.599831][  T453]  tbf_dequeue+0x6b1/0x1098 [sch_tbf]
[  127.599988][  T453]  __qdisc_run+0x169/0x1900

The right thing to do in #1b is to grab the skb off gso_skb queue.
This patchset fixes that issue by changing #1b to use qdisc_dequeue_peeked()
method instead.

Fixes: e13e02a ("net_sched: SFB flow scheduler")
Signed-off-by: Victor Nogueria <victor@mojatatu.com>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20260430152957.194015-3-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
Jamal Hadi Salim says:

====================
Replace direct dequeue call with qdisc_dequeue_peeked

When sfb and red qdiscs have children (eg qfq qdisc) whose peek() callback is
qdisc_peek_dequeued(), we could get a kernel panic. When the parent of such
qdiscs (eg illustrated in patch jonsmirl#3 as tbf) wants to retrieve an skb from
its child (red/sfb in this case), it will do the following:
 1a. do a peek() - and when sensing there's an skb the child can offer, then
     - the child in this case(red/sfb) calls its child's (qfq) peek.
        qfq does the right thing and will return the gso_skb queue packet.
        Note: if there wasnt a gso_skb entry then qfq will store it there.
 1b. invoke a dequeue() on the child (red/sfb). And herein lies the problem.
     - red/sfb will call the child's dequeue() which will essentially just
       try to grab something of qfq's queue.

The right thing to do in #1b is to grab the skb off gso_skb queue.
This patchset fixes that issue by changing #1b to use qdisc_dequeue_peeked()
method instead.

Patch 1 fixes the issue for red qdisc. Patch 2 fixes it for sfb.
Patch 3 adds testcases for the two setups.
====================

Link: https://patch.msgid.link/20260430152957.194015-1-jhs@mojatatu.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
syzbot reports for sleeping function called from invalid context [1].
The recently added code for resizable hash tables uses
hlist_bl bit locks in combination with spin_lock for
the connection fields (cp->lock).

Fix the following problems:

* avoid using spin_lock(&cp->lock) under locked bit lock
because it sleeps on PREEMPT_RT

* as the recent changes call ip_vs_conn_hash() only for newly
allocated connection, the spin_lock can be removed there because
the connection is still not linked to table and does not need
cp->lock protection.

* the lock can be removed also from ip_vs_conn_unlink() where we
are the last connection user.

* the last place that is fixed is ip_vs_conn_fill_cport()
where now the cp->lock is locked before the other locks to
ensure other packets do not modify the cp->flags in non-atomic
way. Here we make sure cport and flags are changed only once
if two or more packets race to fill the cport. Also, we fill
cport early, so that if we race with resizing there will be
valid cport key for the hashing. Add a warning if too many
hash table changes occur for our RCU read-side critical
section which is error condition but minor because the
connection still can expire gracefully. Still, restore the
cport to 0 to allow retransmitted packet to properly fill
the cport. Problems reported by Sashiko.

[1]:
BUG: sleeping function called from invalid context at kernel/locking/spinlock_rt.c:48
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 16, name: ktimers/0
preempt_count: 2, expected: 0
RCU nest depth: 3, expected: 3
8 locks held by ktimers/0/16:
 #0: ffffffff8de5f260 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #1: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #2: ffff8880b8826360 (&base->expiry_lock){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #2: ffff8880b8826360 (&base->expiry_lock){+...}-{3:3}, at: timer_base_lock_expiry kernel/time/timer.c:1502 [inline]
 #2: ffff8880b8826360 (&base->expiry_lock){+...}-{3:3}, at: __run_timer_base+0x120/0x9f0 kernel/time/timer.c:2384
 jonsmirl#3: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 jonsmirl#3: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 jonsmirl#3: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: __rt_spin_lock kernel/locking/spinlock_rt.c:50 [inline]
 jonsmirl#3: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rt_spin_lock+0x1e0/0x400 kernel/locking/spinlock_rt.c:57
 #4: ffffc90000157a80 ((&cp->timer)){+...}-{0:0}, at: call_timer_fn+0xd4/0x5e0 kernel/time/timer.c:1745
 #5: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:300 [inline]
 #5: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:838 [inline]
 #5: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: ip_vs_conn_unlink net/netfilter/ipvs/ip_vs_conn.c:315 [inline]
 #5: ffffffff8dfc80c0 (rcu_read_lock){....}-{1:3}, at: ip_vs_conn_expire+0x257/0x2390 net/netfilter/ipvs/ip_vs_conn.c:1260
 #6: ffffffff8de5f260 (local_bh){.+.+}-{1:3}, at: __local_bh_disable_ip+0x3c/0x420 kernel/softirq.c:163
 #7: ffff888068d4c3f0 (&cp->lock#2){+...}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:45 [inline]
 #7: ffff888068d4c3f0 (&cp->lock#2){+...}-{3:3}, at: ip_vs_conn_unlink net/netfilter/ipvs/ip_vs_conn.c:324 [inline]
 #7: ffff888068d4c3f0 (&cp->lock#2){+...}-{3:3}, at: ip_vs_conn_expire+0xd4a/0x2390 net/netfilter/ipvs/ip_vs_conn.c:1260
Preemption disabled at:
[<ffffffff898a6358>] bit_spin_lock include/linux/bit_spinlock.h:38 [inline]
[<ffffffff898a6358>] hlist_bl_lock+0x18/0x110 include/linux/list_bl.h:149
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Tainted: G        W    L      syzkaller #0 PREEMPT_{RT,(full)}
Tainted: [W]=WARN, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
 __might_resched+0x329/0x480 kernel/sched/core.c:9162
 __rt_spin_lock kernel/locking/spinlock_rt.c:48 [inline]
 rt_spin_lock+0xc2/0x400 kernel/locking/spinlock_rt.c:57
 spin_lock include/linux/spinlock_rt.h:45 [inline]
 ip_vs_conn_unlink net/netfilter/ipvs/ip_vs_conn.c:324 [inline]
 ip_vs_conn_expire+0xd4a/0x2390 net/netfilter/ipvs/ip_vs_conn.c:1260
 call_timer_fn+0x192/0x5e0 kernel/time/timer.c:1748
 expire_timers kernel/time/timer.c:1799 [inline]
 __run_timers kernel/time/timer.c:2374 [inline]
 __run_timer_base+0x6a3/0x9f0 kernel/time/timer.c:2386
 run_timer_base kernel/time/timer.c:2395 [inline]
 run_timer_softirq+0xb7/0x170 kernel/time/timer.c:2405
 handle_softirqs+0x1de/0x6d0 kernel/softirq.c:622
 __do_softirq kernel/softirq.c:656 [inline]
 run_ktimerd+0x69/0x100 kernel/softirq.c:1151
 smpboot_thread_fn+0x541/0xa50 kernel/smpboot.c:160
 kthread+0x388/0x470 kernel/kthread.c:436
 ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
 </TASK>

Reported-by: syzbot+504e778ddaecd36fdd17@syzkaller.appspotmail.com
Link: https://sashiko.dev/#/patchset/20260415200216.79699-1-ja%40ssi.bg
Link: https://sashiko.dev/#/patchset/20260420165539.85174-4-ja%40ssi.bg
Link: https://sashiko.dev/#/patchset/20260422135823.50489-4-ja%40ssi.bg
Fixes: 2fa7cc9 ("ipvs: switch to per-net connection table")
Signed-off-by: Julian Anastasov <ja@ssi.bg>
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 13, 2026
Pavan Chebbi says:

====================
bnxt_en: Bug fixes

This patchset adds the following fixes for bnxt:

Patch #1 fixes DPC AER handling to make it more reliable

Patch #2 fixes incorrect capping bp->max_tpa based on what the FW
supports

Patch jonsmirl#3 fixes ignoring of VNIC configuration result when RDMA
driver is loading

Patch #4 fixes logic to make phase adjustment on the PPS OUT signal
====================

Link: https://patch.msgid.link/20260504083611.1383776-1-pavan.chebbi@broadcom.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 20, 2026
The generic/642 test-case can reproduce the kernel crash:

[40243.605254] ------------[ cut here ]------------
[40243.605956] kernel BUG at fs/ceph/xattr.c:918!
[40243.607142] Oops: invalid opcode: 0000 [#1] SMP PTI
[40243.608067] CPU: 7 UID: 0 PID: 498762 Comm: kworker/7:1 Not tainted 7.0.0-rc7+ jonsmirl#3 PREEMPT(full)
[40243.609700] Hardware name: QEMU Ubuntu 25.10 PC v2 (i440FX + PIIX, + 10.1 machine, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
[40243.611820] Workqueue: ceph-msgr ceph_con_workfn
[40243.612715] RIP: 0010:__ceph_build_xattrs_blob+0x1b8/0x1e0
[40243.613731] Code: 0f 84 82 fe ff ff e9 cf 8e 56 ff 48 8d 65 e8 31 c0 5b 41 5c 41 5d 5d 31 d2 31 c9 31 f6 31 ff 45 31 c0 45 31 c9 c3 cc cc cc cc <0f> 0b 4c 8b 62 08 41 8b 85 24 07 00 00 49 83 c4 04 41 89 44 24 fc
[40243.616888] RSP: 0018:ffffcc80c4d4b688 EFLAGS: 00010287
[40243.617773] RAX: 0000000000010026 RBX: 0000000000000001 RCX: 0000000000000000
[40243.618928] RDX: ffff8a773798dee0 RSI: 0000000000000000 RDI: 0000000000000000
[40243.620158] RBP: ffffcc80c4d4b6a0 R08: 0000000000000000 R09: 0000000000000000
[40243.621573] R10: 0000000000000000 R11: 0000000000000000 R12: ffff8a75f3b58000
[40243.622907] R13: ffff8a75f3b58000 R14: 0000000000000080 R15: 000000000000bffd
[40243.624054] FS:  0000000000000000(0000) GS:ffff8a787d1b4000(0000) knlGS:0000000000000000
[40243.625331] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[40243.626269] CR2: 000072f390b623c0 CR3: 000000011c02a003 CR4: 0000000000372ef0
[40243.627408] Call Trace:
[40243.627839]  <TASK>
[40243.628188]  __prep_cap+0x3fd/0x4a0
[40243.628789]  ? do_raw_spin_unlock+0x4e/0xe0
[40243.629474]  ceph_check_caps+0x46a/0xc80
[40243.630094]  ? __lock_acquire+0x4a2/0x2650
[40243.630773]  ? find_held_lock+0x31/0x90
[40243.631347]  ? handle_cap_grant+0x79f/0x1060
[40243.632068]  ? lock_release+0xd9/0x300
[40243.632696]  ? __mutex_unlock_slowpath+0x3e/0x340
[40243.633429]  ? lock_release+0xd9/0x300
[40243.634052]  handle_cap_grant+0xcf6/0x1060
[40243.634745]  ceph_handle_caps+0x122b/0x2110
[40243.635415]  mds_dispatch+0x5bd/0x2160
[40243.636034]  ? ceph_con_process_message+0x65/0x190
[40243.636828]  ? lock_release+0xd9/0x300
[40243.637431]  ceph_con_process_message+0x7a/0x190
[40243.638184]  ? kfree+0x311/0x4f0
[40243.638749]  ? kfree+0x311/0x4f0
[40243.639268]  process_message+0x16/0x1a0
[40243.639915]  ? sg_free_table+0x39/0x90
[40243.640572]  ceph_con_v2_try_read+0xf58/0x2120
[40243.641255]  ? lock_acquire+0xc8/0x300
[40243.641863]  ceph_con_workfn+0x151/0x820
[40243.642493]  process_one_work+0x22f/0x630
[40243.643093]  ? process_one_work+0x254/0x630
[40243.643770]  worker_thread+0x1e2/0x400
[40243.644332]  ? __pfx_worker_thread+0x10/0x10
[40243.645020]  kthread+0x109/0x140
[40243.645560]  ? __pfx_kthread+0x10/0x10
[40243.646125]  ret_from_fork+0x3f8/0x480
[40243.646752]  ? __pfx_kthread+0x10/0x10
[40243.647316]  ? __pfx_kthread+0x10/0x10
[40243.647919]  ret_from_fork_asm+0x1a/0x30
[40243.648556]  </TASK>
[40243.648902] Modules linked in: overlay hctr2 libpolyval chacha libchacha adiantum libnh libpoly1305 essiv intel_rapl_msr intel_rapl_common intel_uncore_frequency_common skx_edac_common nfit kvm_intel kvm irqbypass joydev ghash_clmulni_intel aesni_intel rapl input_leds mac_hid psmouse vga16fb serio_raw vgastate floppy i2c_piix4 pata_acpi bochs qemu_fw_cfg i2c_smbus sch_fq_codel rbd dm_crypt msr parport_pc ppdev lp parport efi_pstore
[40243.654766] ---[ end trace 0000000000000000 ]---

Commit d93231a ("ceph: prevent a client from exceeding the MDS
maximum xattr size") moved the required_blob_size computation to before
the __build_xattrs() call, introducing a race.

__build_xattrs() releases and reacquires i_ceph_lock during execution.
In that window, handle_cap_grant() may update i_xattrs.blob with a
newer MDS-provided blob and bump i_xattrs.version.  When
__build_xattrs() detects that index_version < version, it destroys and
rebuilds the entire xattr rb-tree from the new blob, potentially
increasing count, names_size, and vals_size.

The prealloc_blob size check that follows still uses the stale
required_blob_size computed before the rebuild, so it passes even when
prealloc_blob is too small for the now-larger tree. After __set_xattr()
adds one more xattr on top, __ceph_build_xattrs_blob() is called from
the cap flush path and hits:

    BUG_ON(need > ci->i_xattrs.prealloc_blob->alloc_len);

Fix this by recomputing required_blob_size after __build_xattrs()
returns, using the current tree state. Also re-validate against
m_max_xattr_size to fall back to the sync path if the rebuilt tree now
exceeds the MDS limit.

Cc: stable@vger.kernel.org
Fixes: d93231a ("ceph: prevent a client from exceeding the MDS maximum xattr size")
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Reviewed-by: Alex Markuze <amarkuze@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request May 22, 2026
The current implementation uses pci_num_vf() while holding the
memory_lock to prevent changing the power state of a PF when
VFs are enabled. This creates a lockdep circular dependency
warning because memory_lock is held during device probing.

[  286.997167] ======================================================
[  287.003363] WARNING: possible circular locking dependency detected
[  287.009562] 7.0.0-dbg-DEV jonsmirl#3 Tainted: G S
[  287.015074] ------------------------------------------------------
[  287.021270] vfio_pci_sriov_/18636 is trying to acquire lock:
[  287.026942] ff45bea2294d4968 (&vdev->memory_lock){+.+.}-{4:4}, at:
vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.036530]
[  287.036530] but task is already holding lock:
[  287.042383] ff45bea3a96b8230 (&new_dev_set->lock){+.+.}-{4:4}, at:
vfio_group_fops_unl_ioctl+0x44d/0x7b0
[  287.051879]
[  287.051879] which lock already depends on the new lock.
[  287.051879]
[  287.060070]
[  287.060070] the existing dependency chain (in reverse order) is:
[  287.067568]
[  287.067568] -> #2 (&new_dev_set->lock){+.+.}-{4:4}:
[  287.073941]        __mutex_lock+0x92/0xb80
[  287.078058]        vfio_assign_device_set+0x66/0x1b0
[  287.083042]        vfio_pci_core_register_device+0xd1/0x2a0
[  287.088638]        vfio_pci_probe+0xd2/0x100
[  287.092933]        local_pci_probe_callback+0x4d/0xa0
[  287.098001]        process_scheduled_works+0x2ca/0x680
[  287.103158]        worker_thread+0x1e8/0x2f0
[  287.107452]        kthread+0x10c/0x140
[  287.111230]        ret_from_fork+0x18e/0x360
[  287.115519]        ret_from_fork_asm+0x1a/0x30
[  287.119983]
[  287.119983] -> #1 ((work_completion)(&arg.work)){+.+.}-{0:0}:
[  287.127219]        __flush_work+0x345/0x490
[  287.131429]        pci_device_probe+0x2e3/0x490
[  287.135979]        really_probe+0x1f9/0x4e0
[  287.140180]        __driver_probe_device+0x77/0x100
[  287.145079]        driver_probe_device+0x1e/0x110
[  287.149803]        __device_attach_driver+0xe3/0x170
[  287.154789]        bus_for_each_drv+0x125/0x150
[  287.159346]        __device_attach+0xca/0x1a0
[  287.163720]        device_initial_probe+0x34/0x50
[  287.168445]        pci_bus_add_device+0x6e/0x90
[  287.172995]        pci_iov_add_virtfn+0x3c9/0x3e0
[  287.177719]        sriov_add_vfs+0x2c/0x60
[  287.181838]        sriov_enable+0x306/0x4a0
[  287.186038]        vfio_pci_core_sriov_configure+0x184/0x220
[  287.191715]        sriov_numvfs_store+0xd9/0x1c0
[  287.196351]        kernfs_fop_write_iter+0x13f/0x1d0
[  287.201338]        vfs_write+0x2be/0x3b0
[  287.205286]        ksys_write+0x73/0x100
[  287.209233]        do_syscall_64+0x14d/0x750
[  287.213529]        entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.219120]
[  287.219120] -> #0 (&vdev->memory_lock){+.+.}-{4:4}:
[  287.225491]        __lock_acquire+0x14c6/0x2800
[  287.230048]        lock_acquire+0xd3/0x2f0
[  287.234168]        down_write+0x3a/0xc0
[  287.238019]        vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.243436]        __rpm_callback+0x8c/0x310
[  287.247730]        rpm_resume+0x529/0x6f0
[  287.251765]        __pm_runtime_resume+0x68/0x90
[  287.256402]        vfio_pci_core_enable+0x44/0x310
[  287.261216]        vfio_pci_open_device+0x1c/0x80
[  287.265947]        vfio_df_open+0x10f/0x150
[  287.270148]        vfio_group_fops_unl_ioctl+0x4a4/0x7b0
[  287.275476]        __se_sys_ioctl+0x71/0xc0
[  287.279679]        do_syscall_64+0x14d/0x750
[  287.283975]        entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.289559]
[  287.289559] other info that might help us debug this:
[  287.289559]
[  287.297582] Chain exists of:
[  287.297582]   &vdev->memory_lock --> (work_completion)(&arg.work)
--> &new_dev_set->lock
[  287.297582]
[  287.310023]  Possible unsafe locking scenario:
[  287.310023]
[  287.315961]        CPU0                    CPU1
[  287.320510]        ----                    ----
[  287.325059]   lock(&new_dev_set->lock);
[  287.328917]
lock((work_completion)(&arg.work));
[  287.336153]                                lock(&new_dev_set->lock);
[  287.342523]   lock(&vdev->memory_lock);
[  287.346382]
[  287.346382]  *** DEADLOCK ***
[  287.346382]
[  287.352315] 2 locks held by vfio_pci_sriov_/18636:
[  287.357125]  #0: ff45bea208ed3e18 (&group->group_lock){+.+.}-{4:4},
at: vfio_group_fops_unl_ioctl+0x3e3/0x7b0
[  287.367048]  #1: ff45bea3a96b8230 (&new_dev_set->lock){+.+.}-{4:4},
at: vfio_group_fops_unl_ioctl+0x44d/0x7b0
[  287.376976]
[  287.376976] stack backtrace:
[  287.381353] CPU: 191 UID: 0 PID: 18636 Comm: vfio_pci_sriov_
Tainted: G S                  7.0.0-dbg-DEV jonsmirl#3 PREEMPTLAZY
[  287.381355] Tainted: [S]=CPU_OUT_OF_SPEC
[  287.381356] Call Trace:
[  287.381357]  <TASK>
[  287.381358]  dump_stack_lvl+0x54/0x70
[  287.381361]  print_circular_bug+0x2e1/0x300
[  287.381363]  check_noncircular+0xf9/0x120
[  287.381364]  ? __lock_acquire+0x5b4/0x2800
[  287.381366]  __lock_acquire+0x14c6/0x2800
[  287.381368]  ? pci_mmcfg_read+0x4f/0x220
[  287.381370]  ? pci_mmcfg_write+0x57/0x220
[  287.381371]  ? lock_acquire+0xd3/0x2f0
[  287.381373]  ? pci_mmcfg_write+0x57/0x220
[  287.381374]  ? lock_release+0xef/0x360
[  287.381376]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381377]  lock_acquire+0xd3/0x2f0
[  287.381378]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381379]  ? lock_is_held_type+0x76/0x100
[  287.381382]  down_write+0x3a/0xc0
[  287.381382]  ? vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381383]  vfio_pci_core_runtime_resume+0x1f/0xa0
[  287.381384]  ? __pfx_pci_pm_runtime_resume+0x10/0x10
[  287.381385]  __rpm_callback+0x8c/0x310
[  287.381386]  ? ktime_get_mono_fast_ns+0x3d/0xb0
[  287.381389]  ? __pfx_pci_pm_runtime_resume+0x10/0x10
[  287.381390]  rpm_resume+0x529/0x6f0
[  287.381392]  ? lock_is_held_type+0x76/0x100
[  287.381394]  __pm_runtime_resume+0x68/0x90
[  287.381396]  vfio_pci_core_enable+0x44/0x310
[  287.381398]  vfio_pci_open_device+0x1c/0x80
[  287.381399]  vfio_df_open+0x10f/0x150
[  287.381401]  vfio_group_fops_unl_ioctl+0x4a4/0x7b0
[  287.381402]  __se_sys_ioctl+0x71/0xc0
[  287.381404]  do_syscall_64+0x14d/0x750
[  287.381405]  ? entry_SYSCALL_64_after_hwframe+0x77/0x7f
[  287.381406]  ? trace_irq_disable+0x25/0xd0
[  287.381409]  entry_SYSCALL_64_after_hwframe+0x77/0x7f

Introduce a private flag 'sriov_active' in the vfio_pci_core_device
struct. This  allows the driver to track the SR-IOV power state requirement
without  relying on pci_num_vf() while holding the memory_lock. The lock is
now  only held to set the flag and ensure the device is in D0, after which
pci_enable_sriov() can be called without the lock.

Fixes: f4162eb ("vfio/pci: Change the PF power state to D0 before enabling VFs")
Cc: stable@vger.kernel.org
Suggested-by: Jason Gunthorpe <jgg@ziepe.ca>
Suggested-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
Link: https://lore.kernel.org/r/20260514173449.3282188-1-rananta@google.com
[promote bitfield to plain bool to avoid storage-unit races]
Signed-off-by: Alex Williamson <alex@shazbot.org>
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Jun 29, 2026
vntb_epf_peer_db_set() raises an MSI interrupt to notify the RC side of
a doorbell event. pci_epc_raise_irq(..., PCI_IRQ_MSI, interrupt_num)
takes a 1-based MSI interrupt number.

The ntb_hw_epf driver reserves MSI #1 for link events, so doorbells
would naturally start at MSI #2 (doorbell bit 0 -> MSI #2). However,
pci-epf-vntb has historically applied an extra offset and mapped doorbell
bit 0 to MSI jonsmirl#3. This matches the legacy behavior of ntb_hw_epf and has
been preserved since commit e35f56b ("PCI: endpoint: Support NTB
transfer between RC and EP").

This offset has not surfaced as a functional issue because:

  - ntb_hw_epf typically allocates enough MSI vectors, so the off-by-one
    still hits a valid MSI vector, and

  - ntb_hw_epf does not implement .db_vector_count()/.db_vector_mask(), so
    client drivers such as ntb_transport effectively ignore the vector
    number and schedule all QPs.

Correcting the MSI number would break interoperability with peers
running older kernels.

Document the legacy offset to avoid confusion when enabling
per-db-vector handling.

Signed-off-by: Koichiro Den <den@valinux.co.jp>
Signed-off-by: Manivannan Sadhasivam <mani@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Frank Li <Frank.Li@nxp.com>
Link: https://patch.msgid.link/20260513024923.451765-2-den@valinux.co.jp
awilliam pushed a commit to awilliam/linux-vfio that referenced this pull request Jul 17, 2026
Wongi and Jungwoo decoded and reported a non-leader exec() related race
which can result in an UAF:

 sys_timer_delete()			exec()
   posix_cpu_timer_del()
   // Observes old leader
   p = pid_task(pid, pid_type);		de_thread()
   					  switch_leader();
					  release_task(old_leader)
					    __exit_signal(old_leader)
					      sighand = lock(old_leader, sighand);
					      posix_cpu_timers*_exit();
   sighand = lock_task_sighand(p)	      unhash_task(old_leader);
     sh = lock(p, sighand)	    	      old_leader->sighand = NULL;
					      unlock(sighand);
     (p->sighand == NULL)
	unlock(sh)
	return NULL;

   // Returns without action
   if(!sighand)
      return 0;
   free_posix_timer();

This is "harmless" unless the deleted timer was armed and enqueued in
p->signal because on exec() a TGID targeted timer is inherited.

As sys_timer_delete() freed the underlying posix timer object
run_posix_cpu_timers() or any timerqueue related add/delete operations on
other timers will access the freed object's timerqueue node, which results
in an UAF.

There is a similar problem vs. posix_cpu_timer_set(). For regular posix
timers it just transiently returns -ESRCH to user space, but for the use
case in do_cpu_nanosleep() it's the same UAF just that the k_itimer is
allocated on the stack.

Also posix_cpu_timer_rearm() fails to rearm the timer, which means it stops
to expire.

While debating solutions Frederic pointed out another problem:

   posix_cpu_timer_del(tmr)
					__exit_signal(p)
					  posix_cpu_timers*_exit(p);
					  unhash_task(p);
					  p->sighand = NULL;
     sh = lock_task_sighand(p)
        sighand = p->sighand;
	if (!sighand)
	    return NULL;
	lock(sighand);

     if (!sh)
	WARN_ON_ONCE(timer_queued(tmr));

On weakly ordered architectures it is not guaranteed that
posix_cpu_timer_del() will observe the stores in posix_cpu_timers*_exit()
when p->sighand is observed as NULL, which means the WARN() can be a false
positive.

Solve these issues by:

  1) Changing the store in __exit_signal() to smp_store_release().

  2) Adding a smp_acquire__after_ctrl_dep() into the !sighand path
     of lock_task_sighand().

  3) Creating a helper function for looking up the task and locking sighand
     which does not return when sighand == NULL. Instead it retries the
     task lookup and only if that fails it gives up.

  4) Using that helper in the three affected functions.

#1/#2 ensures that the reader side which observes sighand == NULL also
observes all preceeding stores, i.e. the stores in posix_cpu_timers*_exit()
and the ones in unhash_task().

jonsmirl#3 ensures that the above described non-leader exec() situation is handled
gracefully. When the task lookup returns the old leader, but sighand ==
NULL then it retries. In the non-leader exec() case the subsequent task
lookup will observe the new leader due to #1/#2. In normal exit() scenarios
the subsequent lookup fails.

When the task lookup fails, the function also checks whether the timer is
still enqueued and issues a warning if that's the case. Unfortunately there
is nothing which can be done about it, but as the task is already not
longer visible the timer should not be accessed anymore. This check also
requires memory ordering, which is not provided when the first lookup
fails. To achieve that the check is preceeded by a smp_rmb() which pairs
with the smp_wmb() in write_seqlock() in __exit_signal(). That ensures that
the stores in posix_cpu_timers*_exit() are visible.

The history of the non-leader exec() issue goes back to the early days of
posix CPU timers, which stored a pointer to the group leader task in the
timer. That obviously fails when a non-leader exec() switches the leader.
commit e0a7021 ("posix-cpu-timers: workaround to suppress the problems
with mt exec") added a temporary workaround for that in 2010 which survived
about 10 years. The fix for the workaround changed the task pointer to a
pid pointer, but failed to see the subtle race described above. So the
Fixes tag picks that commit, which seems to be halfways accurate.

Thanks to Frederic Weissbecker, Oleg Nesterov and Peter Zijlstra for
review, feedback and suggestions and to Wongi and Jungwoo for the excellent
bug report and analysis!

Fixes: 55e8c8e ("posix-cpu-timers: Store a reference to a pid not a task")
Reported-by: Wongi Lee <qw3rtyp0@gmail.com>
Reported-by: Jungwoo Lee <jwlee2217@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
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