GNU C Library master sources branch master updated. glibc-2.24-317-g739e14f

[tuliom at sourceware dot org]

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http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=739e14f9009ff91e4a8d01776e7269fc8cbd0293

commit 739e14f9009ff91e4a8d01776e7269fc8cbd0293
Author: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Date:   Fri Oct 28 18:31:24 2016 -0200

    Document a behavior of an elided pthread_rwlock_unlock
    
    Explain that pthread_rwlock_unlock may crash if called on a lock not
    held by the current thread.

diff --git a/ChangeLog b/ChangeLog
index 4f76008..d5b3f7b 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2016-10-28  Tulio Magno Quites Machado Filho  <tuliom@linux.vnet.ibm.com>
 
+	* nptl/pthread_rwlock_unlock.c: Add a comment explaining its
+	behavior when eliding a lock not held by the current thread.
+	* sysdeps/powerpc/nptl/elide.h: Likewise.
+
+2016-10-28  Tulio Magno Quites Machado Filho  <tuliom@linux.vnet.ibm.com>
+
 	[BZ #20728]
 	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S: Replace a
 	branch to _exit() by a function call.
diff --git a/nptl/pthread_rwlock_unlock.c b/nptl/pthread_rwlock_unlock.c
index a6cadd4..112f748 100644
--- a/nptl/pthread_rwlock_unlock.c
+++ b/nptl/pthread_rwlock_unlock.c
@@ -35,6 +35,10 @@ __pthread_rwlock_unlock (pthread_rwlock_t *rwlock)
 
   LIBC_PROBE (rwlock_unlock, 1, rwlock);
 
+  /* Trying to elide an unlocked lock may crash the process.  This
+     is expected and is compatible with POSIX.1-2008: "results are
+     undefined if the read-write lock rwlock is not held by the
+     calling thread".  */
   if (ELIDE_UNLOCK (rwlock->__data.__writer == 0
 		    && rwlock->__data.__nr_readers == 0))
     return 0;
diff --git a/sysdeps/powerpc/nptl/elide.h b/sysdeps/powerpc/nptl/elide.h
index 77bd82e..835fd92 100644
--- a/sysdeps/powerpc/nptl/elide.h
+++ b/sysdeps/powerpc/nptl/elide.h
@@ -102,6 +102,9 @@ __elide_unlock (int is_lock_free)
 {
   if (is_lock_free)
     {
+      /* This code is expected to crash when trying to unlock a lock not
+	 held by this thread.  More information is available in the
+	 __pthread_rwlock_unlock() implementation.  */
       __libc_tend (0);
       return true;
     }

http://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commitdiff;h=ce193f551ec21df85c934626a21730881484dcf0

commit ce193f551ec21df85c934626a21730881484dcf0
Author: Tulio Magno Quites Machado Filho <tuliom@linux.vnet.ibm.com>
Date:   Fri Oct 21 15:19:10 2016 -0200

    powerpc: Fix TOC stub on powerpc64 clone()
    
    Use a function call to _exit() so that the linker can create a TOC stub
    instead of just a branch.
    
    Tested on powerpc64.

diff --git a/ChangeLog b/ChangeLog
index 27a0194..4f76008 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2016-10-28  Tulio Magno Quites Machado Filho  <tuliom@linux.vnet.ibm.com>
+
+	[BZ #20728]
+	* sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S: Replace a
+	branch to _exit() by a function call.
+
 2016-10-28  Florian Weimer  <fweimer@redhat.com>
 
 	* malloc/malloc.c: Update chunk layout comments.
diff --git a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
index 7c59b9b..df824f5 100644
--- a/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
+++ b/sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S
@@ -97,7 +97,7 @@ L(oldpid):
 #ifdef SHARED
 	b	JUMPTARGET(__GI__exit)
 #else
-	b	JUMPTARGET(_exit)
+	bl	JUMPTARGET(_exit)
 	/* We won't ever get here but provide a nop so that the linker
 	   will insert a toc adjusting stub if necessary.  */
 	nop

-----------------------------------------------------------------------

Summary of changes:
 ChangeLog                                         |   12 ++++++++++++
 nptl/pthread_rwlock_unlock.c                      |    4 ++++
 sysdeps/powerpc/nptl/elide.h                      |    3 +++
 sysdeps/unix/sysv/linux/powerpc/powerpc64/clone.S |    2 +-
 4 files changed, 20 insertions(+), 1 deletions(-)


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