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authorSiddhesh Poyarekar <siddhesh@redhat.com>2013-09-03 09:29:01 +0530
committerSiddhesh Poyarekar <siddhesh@redhat.com>2013-09-03 09:29:01 +0530
commit6c8bbad92726eeb50c9bb4107dad80155062eb0a (patch)
tree668cb7fc9fb6e93914a49660c6ed9733801e619b
parent18d4371683fbe347bf4fbaef05d18b5a4918887a (diff)
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Mark success return value as volatile to work around rescheduling
Resolves #15921

The test case nptl/tst-cleanup2 fails on s390x and power6 due to
instruction sheduling in gcc.  This was reported in gcc:

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=58034

but it was concluded that gcc is allowed to assume that the first
argument to sprintf is a character array - NULL not being a valid
character array.
-rw-r--r--NEWS2
-rw-r--r--nptl/ChangeLog6
-rw-r--r--nptl/tst-cleanup2.c8
3 files changed, 14 insertions, 2 deletions
diff --git a/NEWS b/NEWS
index 17e8eb6637..7ac718f528 100644
--- a/NEWS
+++ b/NEWS
@@ -10,7 +10,7 @@ Version 2.19
 * The following bugs are resolved with this release:
 
   14155, 14699, 15522, 15531, 15532, 15736, 15749, 15797, 15867, 15890,
-  15897, 15905, 15909.
+  15897, 15905, 15909, 15921.
 
 * CVE-2013-4237 The readdir_r function could write more than NAME_MAX bytes
   to the d_name member of struct dirent, or omit the terminating NUL
diff --git a/nptl/ChangeLog b/nptl/ChangeLog
index d1efbb43e5..7511f701ec 100644
--- a/nptl/ChangeLog
+++ b/nptl/ChangeLog
@@ -1,3 +1,9 @@
+2013-09-03  Siddhesh Poyarekar  <siddhesh@redhat.com>
+
+	[BZ #15921]
+	* tst-cleanup2.c (do_test): New volatile variable RET to
+	return success.
+
 2013-08-30   Ondřej Bílka  <neleai@seznam.cz>
 
 	* sysdeps/pthread/pthread.h: Fix typos.
diff --git a/nptl/tst-cleanup2.c b/nptl/tst-cleanup2.c
index 5bd16095a6..65af0f2018 100644
--- a/nptl/tst-cleanup2.c
+++ b/nptl/tst-cleanup2.c
@@ -34,6 +34,12 @@ static int
 do_test (void)
 {
   char *p = NULL;
+  /* gcc can overwrite the success written value by scheduling instructions
+     around sprintf.  It is allowed to do this since according to C99 the first
+     argument of sprintf is a character array and NULL is not a valid character
+     array.  Mark the return value as volatile so that it gets reloaded on
+     return.  */
+  volatile int ret = 0;
   struct sigaction sa;
 
   sa.sa_handler = sig_handler;
@@ -50,7 +56,7 @@ do_test (void)
   if (setjmp (jmpbuf))
     {
       puts ("Exiting main...");
-      return 0;
+      return ret;
     }
 
   sprintf (p, "This should segv\n");