[2018-02] [threads] Fix race between abort socket syscall and thread shutdown #7521
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The race happens when we call mono_thread_info_abort_socket_sycall_for_close on a thread that's about to shut down. We lookup the MonoThreadInfo for that thread outside the mono_thread_info_suspend_lock, and then use it to send the signal once we've taken the lock. In between those two actions, the other thread already finished unregister_thread and pthreads may already have destroyed its TLS keys and otherwise started to dismantle the thread. The fix is to do a second mono_thread_info_lookup once we have the lock and only signal the other thread if it still around. Fixes mono#6998
Call mono_thread_info_lookup while holding the thread info suspend lock. We no longer need to check for STATE_DETACHED because removing MonoThreadInfo on detach is done while holding the suspend lock.
luhenry
approved these changes
Mar 9, 2018
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@monojenkins build failed |
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Backport of #7507.
/cc @lambdageek