[release/5.0] SafeSocketHandle: avoid potential blocking of finalizer thread - #41668
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When the Socket is Disposed, it attempts to make all on-going operations abort. It does this in a loop, and decides there are no on-going operations when the reference count becomes zero and the handle gets released. SafePipeHandle holds a reference to SafeSocketHandle. This prevents the reference count to drop to zero, and causes the dispose to loop infinitly. When the Socket is disposed from the finalizer thread, it is no longer used for operations and we can skip the loop. This avoids blocking the finalizer thread when the reference count can't drop to zero.
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marklio
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jamshedd
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Approved for RC1 |
antonfirsov
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Sep 1, 2020
geoffkizer
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I don't think it's related. See: #41687 (comment) If no counter-arguments rise, I will merge this in a couple of hours. |
ghost
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Backport of #41508 to release/5.0
/cc @antonfirsov @tmds
Customer Impact
This fixes a critical bug, where sockets could hang the finalizer thread:
NamedPipeServerStreamorNamedPipeClientStreamundisposed on Unix. The Roslyn team faced this issue in their CI.Testing
A test has been added based on the simple repro.
Risk
Low. A finalizer run during a blocking socket operation might be problematic, but this seems to be impossible or very unlikely, since such a call implies a live socket reference, which will prevent finalizer execution.