vmbus_server: always notify that the connection is modified when disconnecting #1817
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…onnecting (microsoft#1809) This change fixes an issue where, if all channels are already reset when a disconnect happens, the server would not invoke `Notifier::modify_connection`. This means that the state such as the interrupt page and monitor pages is not reset, and in the case of OpenHCL the relay is not notified of the disconnect (which can leave host state intact, including monitor pages if MNF is handled by the host). This caused an issue where Linux would occasionally crash during resume from hibernate. When resuming, Linux makes two connections, first to read the memory image, and then to resume normal operations, both using MNF. When the first connection unloads, the overlay pages for the monitor pages were not removed until the reconnect, leading to memory corruption when Linux proceeds to use these pages as normal memory. This change also adds some tests ensuring the notifier is invoked for an unload with open channels, without open channels, and a forced disconnect when a new InitiateContact message is received. --------- Co-authored-by: Copilot <[email protected]>
benhillis
approved these changes
Aug 6, 2025
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This change fixes an issue where, if all channels are already reset when a disconnect happens, the server would not invoke
Notifier::modify_connection. This means that the state such as the interrupt page and monitor pages is not reset, and in the case of OpenHCL the relay is not notified of the disconnect (which can leave host state intact, including monitor pages if MNF is handled by the host).This caused an issue where Linux would occasionally crash during resume from hibernate. When resuming, Linux makes two connections, first to read the memory image, and then to resume normal operations, both using MNF. When the first connection unloads, the overlay pages for the monitor pages were not removed until the reconnect, leading to memory corruption when Linux proceeds to use these pages as normal memory.
This change also adds some tests ensuring the notifier is invoked for an unload with open channels, without open channels, and a forced disconnect when a new InitiateContact message is received.
Cherry-picked from #1809