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List:       glibc-cvs
Subject:    [glibc] pthread/tst-cancel28: Fix barrier re-init race condition
From:       Adhemerval Zanella via Glibc-cvs <glibc-cvs () sourceware ! org>
Date:       2021-09-28 14:40:39
Message-ID: 20210928144039.353A9385801A () sourceware ! org
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https://sourceware.org/git/gitweb.cgi?p=glibc.git;h=9874ca536b1d0662b1cea46af3ce09a4d42aeb32

commit 9874ca536b1d0662b1cea46af3ce09a4d42aeb32
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>

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;
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