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From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: libc-stable@sourceware.org
Cc: fweimer@redhat.com, Stafford Horne <shorne@gmail.com>,
	Adhemerval Zanella <adhemerval.zanella@linaro.org>
Subject: [committed 2.34] pthread/tst-cancel28: Fix barrier re-init race condition
Date: Tue, 14 Dec 2021 10:08:45 +0530	[thread overview]
Message-ID: <20211214043845.3786945-1-siddhesh@sourceware.org> (raw)

From: Stafford Horne <shorne@gmail.com>

When running this test on the OpenRISC port I am working on this test
fails with a timeout.  The test passes when being straced or debugged.
Looking at the code there seems to be a race condition in that:

  1 main thread: calls xpthread_cancel
  2 sub thread : receives cancel signal
  3 sub thread : cleanup routine waits on barrier
  4 main thread: re-inits barrier
  5 main thread: waits on barrier

After getting to 5 the main thread and sub thread wait forever as the 2
barriers are no longer the same.

Removing the barrier re-init seems to fix this issue.  Also, the barrier
does not need to be reinitialized as that is done by default.

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
(cherry picked from commit 9874ca536b1d0662b1cea46af3ce09a4d42aeb32)
---
 sysdeps/pthread/tst-cancel28.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/sysdeps/pthread/tst-cancel28.c b/sysdeps/pthread/tst-cancel28.c
index 627cbc8160..9286c159b3 100644
--- a/sysdeps/pthread/tst-cancel28.c
+++ b/sysdeps/pthread/tst-cancel28.c
@@ -69,7 +69,6 @@ do_test (void)
 
   xpthread_cancel (timer_thread);
 
-  xpthread_barrier_init (&barrier, NULL, 2);
   xpthread_barrier_wait (&barrier);
 
   return 0;
-- 
2.31.1


                 reply	other threads:[~2021-12-14  4:38 UTC|newest]

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