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From: Siddhesh Poyarekar <siddhesh@sourceware.org>
To: glibc-cvs@sourceware.org
Subject: [glibc/release/2.34/master] pthread/tst-cancel28: Fix barrier re-init race condition
Date: Tue, 14 Dec 2021 04:38:04 +0000 (GMT)	[thread overview]
Message-ID: <20211214043804.4C00B3858C60@sourceware.org> (raw)

https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=06865865151579d1aa17d38110060a68b85c5d90

commit 06865865151579d1aa17d38110060a68b85c5d90
Author: Stafford Horne <shorne@gmail.com>
Date:   Sat Sep 25 17:02:06 2021 +0900

    pthread/tst-cancel28: Fix barrier re-init race condition
    
    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)

Diff:
---
 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;


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

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