From: Bart Van Assche <bvanassche@acm.org>
Date: Thu, 19 Apr 2012 11:00:32 +0000 (+0000)
Subject: scheduler, ticket lock: Add memory barriers necessary to avoid a deadlock on PowerPC... 
X-Git-Tag: svn/VALGRIND_3_8_0~353
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=cdc938fcec455d1799061bdcc0a53b9d30128eea;p=thirdparty%2Fvalgrind.git

scheduler, ticket lock: Add memory barriers necessary to avoid a deadlock on PowerPC systems

git-svn-id: svn://svn.valgrind.org/valgrind/trunk@12509
---

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)();