8321509: False positive in get_trampoline fast path causes crash

[bulasevich]

This change is a backport of JDK-8321509.

backport issue №1
This change adds two functions to trampoline_stub_Relocation class. On macos-aarch64 platform it triggers clang to report:

/Users/runner/work/jdk17u-dev/jdk17u-dev/src/hotspot/share/code/relocInfo.hpp:1212:8: error: 'pack_data_to' overrides a member function but is not marked 'override' [-Werror,-Winconsistent-missing-override]
  void pack_data_to(CodeSection * dest);
       ^
   ... (rest of output omitted)

I resolved the issue by adding the override keyword manually (see commit_2). A cleaner solution could be to backport 8298913: Add override qualifiers to Relocation classes, which properly introduces the missing specifier. However, that change introduces additional dependencies (see #3513), so in this context, I’d prefer a minimal, targeted fix for this change only.

backport issue №2
A manual merge was also required due to minor discrepancies between the mainline and jdk17u repositories. The reasons for the manual intervention are as follows:

• Copyright Year
  • The mainline patch updated the copyright from 2023 to 2024
  • In jdk17u the year is still 2021
• NULL -> nullptr conversion
  • mainline deals with nullptr after JDK-8301493: Replace NULL with nullptr in cpu/aarch64
• CodeBlob Lookup Changes
  • on the mainline "JDK-8290025: Remove the Sweeper" changed CodeCache::find_blob_unsafe call to CodeCache::find_blob
  • in jdk17u the old variant is used

See the minor mismatches below. Left: original diff on JDK mainline. Right: diff actually applied

diff --git a/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp b/src/ho    diff --git a/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp b/src/ho
--- a/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp                    --- a/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp
+++ b/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp                    +++ b/src/hotspot/cpu/aarch64/nativeInst_aarch64.cpp
@@ -1,5 +1,5 @@                                                         @@ -1,5 +1,5 @@
 /*                                                                      /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All righ |  - * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All righ
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All righ    + * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All righ
  * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.           * Copyright (c) 2014, 2020, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.         * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *                                                                       *
@@ -158,13 +158,18 @@ void NativeGotJump::verify() const {              @@ -158,13 +158,18 @@ void NativeGotJump::verify() const {
 }                                                                       }

 address NativeCall::destination() const {                               address NativeCall::destination() const {
-  address addr = (address)this;                                        -  address addr = (address)this;
-  address destination = instruction_address() + displacement();        -  address destination = instruction_address() + displacement();
+  address addr = instruction_address();                                +  address addr = instruction_address();
+  address destination = addr + displacement();                         +  address destination = addr + displacement();
+                                                                       +
+  // Performance optimization: no need to call find_blob() if it is    +  // Performance optimization: no need to call find_blob() if it is
+  if (destination == addr) {                                           +  if (destination == addr) {
+    return destination;                                                +    return destination;
+  }                                                                    +  }

   // Do we use a trampoline stub for this call?                           // Do we use a trampoline stub for this call?
   CodeBlob* cb = CodeCache::find_blob(addr);                        |     CodeBlob* cb = CodeCache::find_blob_unsafe(addr);   // Else we get assertion if nmethod is zombie.
-  assert(cb && cb->is_nmethod(), "sanity");                            -  assert(cb && cb->is_nmethod(), "sanity");
-  nmethod *nm = (nmethod *)cb;                                         -  nmethod *nm = (nmethod *)cb;
+  assert(cb != nullptr && cb->is_nmethod(), "nmethod expected");       +  assert(cb != nullptr && cb->is_nmethod(), "nmethod expected");
+  nmethod *nm = cb->as_nmethod();                                      +  nmethod *nm = cb->as_nmethod();
   if (nm->stub_contains(destination) && is_NativeCallTrampolineStub       if (nm->stub_contains(destination) && is_NativeCallTrampolineStub
     // Yes we do, so get the destination from the trampoline stub.          // Yes we do, so get the destination from the trampoline stub.
     const address trampoline_stub_addr = destination;                       const address trampoline_stub_addr = destination;
@@ -211,22 +212,18 @@ void NativeCall::set_destination_mt_safe(addre    @@ -211,22 +212,18 @@ void NativeCall::set_destination_mt_safe(addre
 }                                                                       }

 address NativeCall::get_trampoline() {                                  address NativeCall::get_trampoline() {
-  address call_addr = addr_at(0);                                      -  address call_addr = addr_at(0);
+  address call_addr = instruction_address();                           +  address call_addr = instruction_address();

   CodeBlob *code = CodeCache::find_blob(call_addr);                       CodeBlob *code = CodeCache::find_blob(call_addr);
-  assert(code != nullptr, "Could not find the containing code blob" |  -  assert(code != NULL, "Could not find the containing code blob");
+  assert(code != nullptr && code->is_nmethod(), "nmethod expected")    +  assert(code != nullptr && code->is_nmethod(), "nmethod expected")
+  nmethod* nm = code->as_nmethod();                                    +  nmethod* nm = code->as_nmethod();

-  address bl_destination                                               -  address bl_destination
-    = MacroAssembler::pd_call_destination(call_addr);                  -    = MacroAssembler::pd_call_destination(call_addr);
-  if (code->contains(bl_destination) &&                                -  if (code->contains(bl_destination) &&
+  address bl_destination = call_addr + displacement();                 +  address bl_destination = call_addr + displacement();
+  if (nm->stub_contains(bl_destination) &&                             +  if (nm->stub_contains(bl_destination) &&
       is_NativeCallTrampolineStub_at(bl_destination))                         is_NativeCallTrampolineStub_at(bl_destination))
     return bl_destination;                                                  return bl_destination;

-  if (code->is_nmethod()) {                                            -  if (code->is_nmethod()) {
-    return trampoline_stub_Relocation::get_trampoline_for(call_addr    -    return trampoline_stub_Relocation::get_trampoline_for(call_addr
-  }                                                                    -  }
-                                                                       -
-  return nullptr;                                                   |  -  return NULL;
+  return trampoline_stub_Relocation::get_trampoline_for(call_addr,     +  return trampoline_stub_Relocation::get_trampoline_for(call_addr,
 }                                                                       }

 // Inserts a native call instruction at a given pc                      // Inserts a native call instruction at a given pc
diff --git a/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp b/src/ho    diff --git a/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp b/src/ho
--- a/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp                    --- a/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp
+++ b/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp                    +++ b/src/hotspot/cpu/aarch64/nativeInst_aarch64.hpp
@@ -1,5 +1,5 @@                                                         @@ -1,5 +1,5 @@
 /*                                                                      /*
- * Copyright (c) 1997, 2023, Oracle and/or its affiliates. All righ |  - * Copyright (c) 1997, 2021, Oracle and/or its affiliates. All righ
+ * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All righ    + * Copyright (c) 1997, 2024, Oracle and/or its affiliates. All righ
  * Copyright (c) 2014, 2108, Red Hat Inc. All rights reserved.           * Copyright (c) 2014, 2108, Red Hat Inc. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.         * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *                                                                       *
diff --git a/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp b/src/hot    diff --git a/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp b/src/hot
--- a/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp                     --- a/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp
+++ b/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp                     +++ b/src/hotspot/cpu/aarch64/relocInfo_aarch64.cpp
@@ -60,13 +60,12 @@ void Relocation::pd_set_data_value(address x, in    @@ -60,13 +60,12 @@ void Relocation::pd_set_data_value(address x, in

 address Relocation::pd_call_destination(address orig_addr) {            address Relocation::pd_call_destination(address orig_addr) {
   assert(is_call(), "should be a call here");                             assert(is_call(), "should be a call here");
-  if (NativeCall::is_call_at(addr())) {                                -  if (NativeCall::is_call_at(addr())) {
-    address trampoline = nativeCall_at(addr())->get_trampoline();      -    address trampoline = nativeCall_at(addr())->get_trampoline();
-    if (trampoline) {                                                  -    if (trampoline) {
-      return nativeCallTrampolineStub_at(trampoline)->destination()    -      return nativeCallTrampolineStub_at(trampoline)->destination()
+  if (orig_addr == nullptr) {                                          +  if (orig_addr == nullptr) {
+    if (NativeCall::is_call_at(addr())) {                              +    if (NativeCall::is_call_at(addr())) {
+      NativeCall* call = nativeCall_at(addr());                        +      NativeCall* call = nativeCall_at(addr());
+      return call->destination();                                      +      return call->destination();
     }                                                                       }
-  }                                                                    -  }
-  if (orig_addr != nullptr) {                                       |  -  if (orig_addr != NULL) {
+  } else {                                                             +  } else {
     address new_addr = MacroAssembler::pd_call_destination(orig_add         address new_addr = MacroAssembler::pd_call_destination(orig_add
     // If call is branch to self, don't try to relocate it, just le         // If call is branch to self, don't try to relocate it, just le
     // as branch to self. This happens during code generation if th         // as branch to self. This happens during code generation if th

Testing
Ran tier1-3 on Linux aarch64 (release & slowdebug).

---

Progress

• Change must be properly reviewed (1 review required, with at least 1 Reviewer)
• Change must not contain extraneous whitespace
• Commit message must refer to an issue
• JDK-8321509 needs maintainer approval

Issue

• JDK-8321509: False positive in get_trampoline fast path causes crash (Bug - P3 - Approved)

Reviewers

• Paul Hohensee (@phohensee - Reviewer)

Reviewing

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$ git checkout pull/3441

Update a local copy of the PR:
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$ git pull https://git.openjdk.org/jdk17u-dev.git pull/3441/head

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[bridgekeeper]

👋 Welcome back bulasevich! A progress list of the required criteria for merging this PR into master will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

[openjdk]

@bulasevich This change now passes all automated pre-integration checks.

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After integration, the commit message for the final commit will be:

8321509: False positive in get_trampoline fast path causes crash

Reviewed-by: phh

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At the time when this comment was updated there had been 143 new commits pushed to the master branch:

• 9fe019d: 8356053: Test java/awt/Toolkit/Headless/HeadlessToolkit.java fails by timeout
• e1cda21: 8349492: Update sun/security/pkcs12/KeytoolOpensslInteropTest.java to use a recent Openssl version
• 05cc91a: 8333117: Remove support of remote and manual debuggee launchers
• ... and 140 more: https://git.openjdk.org/jdk17u-dev/compare/c98e598bc4b369abc60a876f7cfb7c78f5521cc1...master

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[openjdk]

This backport pull request has now been updated with issue from the original commit.

[mlbridge]

Webrevs

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[openjdk]

⚠️ @bulasevich This change is now ready for you to apply for maintainer approval. This can be done directly in each associated issue or by using the /approval command.

[bulasevich]

/approval request
Backporting to fix the issue in jdk17u as well. The change has proven stable across multiple releases. The change includes a minor Clang error fix (see PR description). Verified with tier1-4 on AArch64.

[openjdk]

@bulasevich
8321509: The approval request has been created successfully.

[GoeLin]

Thanks for the detailed description of the differences to 21!
I successfully ran this through SAP's testing.