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71 lines
2.0 KiB
71 lines
2.0 KiB
7 years ago
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commit a3e5b4feeb54cb92657ec2bc6d9be1fcef9e8575
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Author: Paul E. Murphy <murphyp@linux.vnet.ibm.com>
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Date: Mon Jan 11 17:24:04 2016 -0500
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Fix race in tst-mqueue5
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The check is done on line 117 by a thread spawned
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from do_child(), forked from do_test(). This test
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generates a signal in the forked process.
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Either thread may handle the signal, and on ppc,
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it happens to be done on do_child, on the thread
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which is not doing the check on line 117.
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This exposes a race condition whereby the test
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incorrectly fails as the signal is caught during
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or after the check.
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This is mitigated by ensuring the signal is blocked
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in the child thread while thread is running.
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2016-01-15 Martin Sebor <msebor@redhat.com>
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[BZ #19432]
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diff --git a/rt/tst-mqueue5.c b/rt/tst-mqueue5.c
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index aa74fa3..25042bc 100644
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--- a/rt/tst-mqueue5.c
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+++ b/rt/tst-mqueue5.c
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@@ -116,7 +116,7 @@ thr (void *arg)
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if (rtmin_cnt != 2)
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{
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- puts ("SIGRTMIN signal in child did not arrive");
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+ puts ("SIGRTMIN signal in thread did not arrive");
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result = 1;
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}
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else if (rtmin_pid != getppid ()
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@@ -403,6 +403,16 @@ do_child (const char *name, pthread_barrier_t *b2, pthread_barrier_t *b3,
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result = 1;
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}
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+ /* Ensure the thr thread gets the signal, not us. */
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+ sigset_t set;
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+ sigemptyset (&set);
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+ sigaddset (&set, SIGRTMIN);
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+ if (pthread_sigmask (SIG_BLOCK, &set, NULL))
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+ {
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+ printf ("Failed to block SIGRTMIN in child: %m\n");
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+ result = 1;
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+ }
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+
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(void) pthread_barrier_wait (b2);
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/* Parent calls mqsend (q), which should wake up mqrecv (q)
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@@ -514,7 +524,14 @@ do_child (const char *name, pthread_barrier_t *b2, pthread_barrier_t *b3,
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result = 1;
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}
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- void *thr_ret;
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+ /* Reenable test signals before cleaning up the thread. */
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+ if (pthread_sigmask (SIG_UNBLOCK, &set, NULL))
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+ {
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+ printf ("Failed to unblock SIGRTMIN in child: %m\n");
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+ result = 1;
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+ }
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+
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+ void *thr_ret;
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ret = pthread_join (th, &thr_ret);
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if (ret)
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{
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