[libcxx-commits] [PATCH] D114119: [libcxx] Fix potential lost wake-up in counting semaphore

Wed Apr 13 11:20:42 PDT 2022

ldionne added a comment.

@fwolff @jiixyj

Woah, I somehow missed the comment on December 14. What an analysis -- my mind is blown TBH, thank you so much @jiixyj for looking into it like that.

If I followed correctly, then yes it makes sense to me, and yes the proposed fix also makes sense. Also, if you re-upload a patch, you should be able to see if it hangs forever (we now enforce a timeout in our CI).

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Comment at: libcxx/test/std/thread/thread.semaphore/lost_wakeup.pass.cpp:15-16
+
+// TODO(ldionne): This test fails on Ubuntu Focal on our CI nodes (and only there), in 32 bit mode.
+// UNSUPPORTED: linux && 32bits-on-64bits
+
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This can be removed now.

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Comment at: libcxx/test/std/thread/thread.semaphore/lost_wakeup.pass.cpp:18
+
+// This is a regression test for PR#47013.
+
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  https://reviews.llvm.org/D114119/new/

https://reviews.llvm.org/D114119