From 6c8bbad92726eeb50c9bb4107dad80155062eb0a Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Tue, 3 Sep 2013 09:29:01 +0530 Subject: 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. --- nptl/ChangeLog | 6 ++++++ nptl/tst-cleanup2.c | 8 +++++++- 2 files changed, 13 insertions(+), 1 deletion(-) (limited to 'nptl') 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 + + [BZ #15921] + * tst-cleanup2.c (do_test): New volatile variable RET to + return success. + 2013-08-30 Ondřej Bílka * 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"); -- cgit 1.4.1