New pthread_barrier algorithm to fulfill barrier destruction requirements.

The previous barrier implementation did not fulfill the POSIX requirements
for when a barrier can be destroyed.  Specifically, it was possible that
threads that haven't noticed yet that their round is complete still access
the barrier's memory, and that those accesses can happen after the barrier
has been legally destroyed.
The new algorithm does not have this issue, and it avoids using a lock
internally.

1 files changed, 27 insertions, 0 deletions

diff --git a/ChangeLog b/ChangeLog
index fb5cd0e024..53413adee4 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,30 @@
+2016-01-15  Torvald Riegel  <triegel@redhat.com>
+
+	[BZ #13065]
+	* nptl/pthread_barrier_wait.c (__pthread_barrier_wait): Replace with
+	new implementation.
+	* nptl/pthread_barrier_destroy.c (pthread_barrier_destroy): Likewise.
+	* nptl/pthread_barrier_init.c (__pthread_barrier_init): Adapt.
+	* sysdeps/nptl/internaltypes.h (pthread_barrier): Adapt.
+	(BARRIER_IN_THRESHOLD): New macro.
+	* nptl/pthread_barrierattr_setpshared.c
+	(pthread_barrierattr_setpshared): Clean up.
+	* nptl/tst-barrier4.c: Correct comment.
+	* nptl/tst-barrier5.c: New file.
+	* nptl/Makefile (tests): Add nptl/tst-barrier5.c.
+	(gen-as-const-headers): Remove lowlevelbarrier.sym.
+	* sysdeps/unix/sysv/linux/i386/pthread_barrier_wait.S: Remove.
+	* sysdeps/unix/sysv/linux/x86_64/pthread_barrier_wait.S: Remove.
+	* nptl/lowlevelbarrier.sym: Remove.
+	* nptl/DESIGN-barrier.txt: Remove.
+	* sysdeps/sparc/nptl/pthread_barrier_destroy.c: Remove.
+	* sysdeps/sparc/nptl/pthread_barrier_init.c: Remove.
+	* sysdeps/sparc/nptl/pthread_barrier_wait.c: Remove.
+	* sysdeps/sparc/sparc32/pthread_barrier_wait.c: Replace with build
+	error.
+	* sysdeps/sparc/sparc32/sparcv9/pthread_barrier_wait.c: Use generic
+	implementation.
+
 2016-01-15  Paul E. Murphy  <murphyp@linux.vnet.ibm.com>
 
 	* rt/tst-mqueue5.c (thr): Cleanup misleading comment.