Clear list of acquired robust mutexes in the child process after forking.

Robust mutexes acquired at the time of a call to fork() do not remain
acquired by the forked child process.  We have to clear the list of
acquired robust mutexes before registering this list with the kernel;
otherwise, if some of the robust mutexes are process-shared, the parent
process can alter the child's robust mutex list, which can lead to
deadlocks or even modification of memory that may not be occupied by a
mutex anymore.

	[BZ #19402]
	* sysdeps/nptl/fork.c (__libc_fork): Clear list of acquired robust
	mutexes.

1 files changed, 6 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index bf7b236b48..b4defdbda2 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2016-01-13  Torvald Riegel  <triegel@redhat.com>
 
+	[BZ #19402]
+	* sysdeps/nptl/fork.c (__libc_fork): Clear list of acquired robust
+	mutexes.
+
+2016-01-13  Torvald Riegel  <triegel@redhat.com>
+
 	[BZ #20985]
 	* nptl/Makefile: Adapt.
 	* nptl/pthread_mutex_cond_lock.c (LLL_ROBUST_MUTEX_LOCK): Remove.