Commit Graph

8 Commits

Author SHA1 Message Date
Joseph Myers
bfff8b1bec Update copyright dates with scripts/update-copyrights. 2017-01-01 00:14:16 +00:00
Adhemerval Zanella
47677f2edc nptl: Fix sem_wait and sem_timedwait cancellation (BZ#18243)
This patch fixes both sem_wait and sem_timedwait cancellation point for
uncontended case.  In this scenario only atomics are involved and thus
the futex cancellable call is not issue and a pending cancellation signal
is not handled.

The fix is straighforward by calling pthread_testcancel is both function
start.  Although it would be simpler to call CANCELLATION_P directly, I
decided to add an internal pthread_testcancel alias and use it to export
less internal implementation on such function.  A possible change on
how pthread_testcancel is internally implemented would lead to either
continue to force use CANCELLATION_P or to adjust its every use.

GLIBC testcase also does have tests for uncontended cases, test-cancel12
and test-cancel14.c,  however both are flawed by adding another
cancellation point just after thread pthread_cleanup_pop:

 47 static void *
 48 tf (void *arg)
 49 {
 50   pthread_cleanup_push (cleanup, NULL);
 51
 52   int e = pthread_barrier_wait (&bar);
 53   if (e != 0 && e != PTHREAD_BARRIER_SERIAL_THREAD)
 54     {
 55       puts ("tf: 1st barrier_wait failed");
 56       exit (1);
 57     }
 58
 59   /* This call should block and be cancelable.  */
 60   sem_wait (&sem);
 61
 62   pthread_cleanup_pop (0);
 63
 64   puts ("sem_wait returned");
 65
 66   return NULL;
 67 }

So sem_{timed}wait does not act on cancellation, pthread_cleanup_pop executes
'cleanup' and then 'puts' acts on cancellation.  Since pthread_cleanup_pop
removed the clean-up handler, it will ran only once and thus it won't accuse
an error to indicate sem_wait has not acted on the cancellation signal.

This patch also fixes this behavior by removing the cancellation point 'puts'.
It also adds some cleanup on all sem_{timed}wait cancel tests.

It partially fixes BZ #18243.  Checked on x86_64.

	[BZ #18243]
	* nptl/pthreadP.h (__pthread_testcancel): Add prototype and hidden_proto.
	* nptl/pthread_testcancel.c (pthread_cancel): Add internal aliais
	definition.
	* nptl/sem_timedwait.c (sem_timedwait): Add cancellation check for
	uncontended case.
	* nptl/sem_wait.c (__new_sem_wait): Likewise.
	* nptl/tst-cancel12.c (cleanup): Remove wrong cancellation point.
	(tf): Fix check for uncontended case.
	(do_test): Likewise.
	* nptl/tst-cancel13.c (cleanup): Remove wrong cancellation point.
	(tf): Fix check for uncontended case.
	(do_test): Likewise.
	* nptl/tst-cancel14.c (cleanup): Remove wrong cancellation point.
	(tf): Fix check for uncontended case.
	(do_test): Likewise.
	* nptl/tst-cancel15.c (cleanup): Remove wrong cancellation point.
	(tf): Fix check for uncontended case.
	(do_test): Likewise.
2016-09-15 11:14:31 -03:00
Joseph Myers
f7a9f785e5 Update copyright dates with scripts/update-copyrights. 2016-01-04 16:05:18 +00:00
Joseph Myers
b168057aaa Update copyright dates with scripts/update-copyrights. 2015-01-02 16:29:47 +00:00
Allan McRae
d4697bc93d Update copyright notices with scripts/update-copyrights 2014-01-01 22:00:23 +10:00
Joseph Myers
568035b787 Update copyright notices with scripts/update-copyrights. 2013-01-02 19:05:09 +00:00
Paul Eggert
59ba27a63a Replace FSF snail mail address with URLs. 2012-02-09 23:18:22 +00:00
Ulrich Drepper
7726edc273 Update.
2003-06-07  Ulrich Drepper  <drepper@redhat.com>

	* cleanup_routine.c: New file.
	* Versions (libpthread) [GLIBC_2.3.3]: Add __pthread_cleanup_routine.
	* sysdeps/pthread/pthread.h: Add support for fully exception-based
	cleanup handling.
	* Makefile (libpthread-routines): Add cleanup_routine.
	Add more CFLAGS variables to compile with exceptions.  Add comments
	why which file needs unwind tables.
	(tests) [have-forced-unwind==yes]: Add tst-cancelx* and tst-cleanupx*
	tests.
	* tst-cancelx1.c: New file.
	* tst-cancelx2.c: New file.
	* tst-cancelx3.c: New file.
	* tst-cancelx4.c: New file.
	* tst-cancelx5.c: New file.
	* tst-cancelx6.c: New file.
	* tst-cancelx7.c: New file.
	* tst-cancelx8.c: New file.
	* tst-cancelx9.c: New file.
	* tst-cancelx10.c: New file.
	* tst-cancelx11.c: New file.
	* tst-cancelx12.c: New file.
	* tst-cancelx13.c: New file.
	* tst-cancelx14.c: New file.
	* tst-cancelx15.c: New file.
	* tst-cleanupx0.c: New file.
	* tst-cleanupx0.expect: New file.
	* tst-cleanupx1.c: New file.
	* tst-cleanupx2.c: New file.
	* tst-cleanupx3.c: New file.

	* tst-cleanup0.c: Make standard compliant.
	* tst-cleanup1.c: Likewise.

	* sysdeps/unix/sysv/linux/sem_timedwait.c: Add cancellation support.
	* sysdeps/unix/sysv/linux/sem_wait.c: Likewise.
	* sysdeps/unix/sysv/linux/i386/i486/sem_timedwait.S: Likewise.
	* sysdeps/unix/sysv/linux/i386/i486/sem_wait.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S: Likewise.
	* sysdeps/unix/sysv/linux/x86_64/sem_wait.S: Likewise.
	* sysdeps/i386/tcb-offsets.sym: Add RESULT, CANCELHANDLING, and
	CLEANUP_JMP_BUF.
	* sysdeps/x86_64/tcb-offsets.sym: Likewise.
	* tst-cancel12.c: New file.
	* tst-cancel13.c: New file.
	* tst-cancel14.c: New file.
	* tst-cancel15.c: New file.
	* Makefile (tests): Add tst-cancel12, tst-cancel13, tst-cancel14,
	and tst-cancel15.

	* tst-cancel1.c: Add some comments.

	* sysdeps/unix/sysv/linux/x86_64/sem_timedwait.S: Compute relative
	timeout correctly.
2003-06-08 05:28:14 +00:00