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| author | Paul E. Murphy <murphyp@linux.vnet.ibm.com> | 2016-01-11 17:24:04 -0500 |
|---|---|---|
| committer | Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com> | 2016-01-15 16:53:08 -0200 |
| commit | a3e5b4feeb54cb92657ec2bc6d9be1fcef9e8575 (patch) | |
| tree | f538c5cf1a10d4d8ec7821cf086df977d5dc8ea3 | |
| parent | 692de4b3960dc90bdcfb871513ee4d81d314cf69 (diff) | |
| download | glibc-a3e5b4feeb54cb92657ec2bc6d9be1fcef9e8575.tar.gz glibc-a3e5b4feeb54cb92657ec2bc6d9be1fcef9e8575.tar.xz glibc-a3e5b4feeb54cb92657ec2bc6d9be1fcef9e8575.zip | |
Fix race in tst-mqueue5
The check is done on line 117 by a thread spawned from do_child(), forked from do_test(). This test generates a signal in the forked process. Either thread may handle the signal, and on ppc, it happens to be done on do_child, on the thread which is not doing the check on line 117. This exposes a race condition whereby the test incorrectly fails as the signal is caught during or after the check. This is mitigated by ensuring the signal is blocked in the child thread while thread is running.
| -rw-r--r-- | ChangeLog | 5 | ||||
| -rw-r--r-- | rt/tst-mqueue5.c | 21 |
2 files changed, 24 insertions, 2 deletions
diff --git a/ChangeLog b/ChangeLog index 7f2a19d50a..fb5cd0e024 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2016-01-15 Paul E. Murphy <murphyp@linux.vnet.ibm.com> + + * rt/tst-mqueue5.c (thr): Cleanup misleading comment. + (do_child): Mask SIGRTMIN while thr is running. + 2016-01-15 Martin Sebor <msebor@redhat.com> [BZ #19432] diff --git a/rt/tst-mqueue5.c b/rt/tst-mqueue5.c index aa74fa31ac..25042bcc9f 100644 --- a/rt/tst-mqueue5.c +++ b/rt/tst-mqueue5.c @@ -116,7 +116,7 @@ thr (void *arg) if (rtmin_cnt != 2) { - puts ("SIGRTMIN signal in child did not arrive"); + puts ("SIGRTMIN signal in thread did not arrive"); result = 1; } else if (rtmin_pid != getppid () @@ -403,6 +403,16 @@ do_child (const char *name, pthread_barrier_t *b2, pthread_barrier_t *b3, result = 1; } + /* Ensure the thr thread gets the signal, not us. */ + sigset_t set; + sigemptyset (&set); + sigaddset (&set, SIGRTMIN); + if (pthread_sigmask (SIG_BLOCK, &set, NULL)) + { + printf ("Failed to block SIGRTMIN in child: %m\n"); + result = 1; + } + (void) pthread_barrier_wait (b2); /* Parent calls mqsend (q), which should wake up mqrecv (q) @@ -514,7 +524,14 @@ do_child (const char *name, pthread_barrier_t *b2, pthread_barrier_t *b3, result = 1; } - void *thr_ret; + /* Reenable test signals before cleaning up the thread. */ + if (pthread_sigmask (SIG_UNBLOCK, &set, NULL)) + { + printf ("Failed to unblock SIGRTMIN in child: %m\n"); + result = 1; + } + + void *thr_ret; ret = pthread_join (th, &thr_ret); if (ret) { |