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From: "gatroubo at squizzy dot net" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug libstdc++/100806] New: deadlock in std::counting_semaphore
Date: Thu, 27 May 2021 21:21:25 +0000	[thread overview]
Message-ID: <bug-100806-4@http.gcc.gnu.org/bugzilla/> (raw)

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=100806

            Bug ID: 100806
           Summary: deadlock in std::counting_semaphore
           Product: gcc
           Version: 11.1.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: libstdc++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gatroubo at squizzy dot net
  Target Milestone: ---

Hi,

there seems to be some sort of deadlock in std::counting_semaphore. In the
following test program, I create 10 threads, each thread tries to acquire a
semaphore (initial value 4), waits 100ms, and then releases the semaphore:

https://wandbox.org/permlink/Zt3d4EC5vNOXtr9W

Most of the time, the program seems to be in a deadlock after 5 threads
acquired/released the semaphore. When I compile and run the same code with
clang 11.1 I get the expected behavoir (all 10 threads aquire/release the
semaphore and the program exits successfully):

https://wandbox.org/permlink/XjQaoyy9C6uiDYlo

Thanks for your effort to create such a great tool!
-Tobias

             reply	other threads:[~2021-05-27 21:21 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-05-27 21:21 gatroubo at squizzy dot net [this message]
2021-05-28 18:08 ` [Bug libstdc++/100806] " rodgertq at gcc dot gnu.org
2021-06-16 18:45 ` rodgertq at gcc dot gnu.org
2021-06-22 18:07 ` cvs-commit at gcc dot gnu.org
2021-06-22 18:08 ` cvs-commit at gcc dot gnu.org
2022-02-14 17:03 ` rodgertq at gcc dot gnu.org
2022-12-24 21:14 ` pinskia at gcc dot gnu.org

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