From cdc938fcec455d1799061bdcc0a53b9d30128eea Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 19 Apr 2012 11:00:32 +0000
Subject: [PATCH] scheduler, ticket lock: Add memory barriers necessary to
 avoid a deadlock on PowerPC systems

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12509
---
 coregrind/m_scheduler/ticket-lock-linux.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/coregrind/m_scheduler/ticket-lock-linux.c b/coregrind/m_scheduler/ticket-lock-linux.c
index 865c79ec3e..e28841cc88 100644
--- a/coregrind/m_scheduler/ticket-lock-linux.c
+++ b/coregrind/m_scheduler/ticket-lock-linux.c
@@ -127,6 +127,7 @@ static void acquire_sched_lock(struct sched_lock *p)
                   VG_(gettid)(), ticket);
    for (;;) {
       futex_value = *futex;
+      __sync_synchronize();
       if (ticket == p->head)
          break;
       if (s_debug)
@@ -142,6 +143,7 @@ static void acquire_sched_lock(struct sched_lock *p)
          vg_assert(False);
       }
    }
+   __sync_synchronize();
    INNER_REQUEST(ANNOTATE_RWLOCK_ACQUIRED(p, /*is_w*/1));
    vg_assert(p->owner == 0);
    p->owner = VG_(gettid)();
-- 
2.47.2