From 4cee6a3812e9e81532f89b5be15d549faf49fffd Mon Sep 17 00:00:00 2001 From: George Dunlap Date: Tue, 10 Apr 2012 10:41:30 +0100 Subject: xen: Fix schedule()'s grabbing of the schedule lock Because the location of the lock can change between the time you read it and the time you grab it, the per-cpu schedule locks need to check after lock acquisition that the lock location hasn't changed, and release and re-try if so. This change was effected throughout the source code, but one very important place was apparently missed: in schedule() itself. Signed-off-by: George Dunlap Committed-by: Keir Fraser --- xen/common/schedule.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) (limited to 'xen/common/schedule.c') diff --git a/xen/common/schedule.c b/xen/common/schedule.c index a1eeac36eb..724e8fa1ab 100644 --- a/xen/common/schedule.c +++ b/xen/common/schedule.c @@ -1075,6 +1075,7 @@ static void schedule(void) bool_t tasklet_work_scheduled = 0; struct schedule_data *sd; struct task_slice next_slice; + int cpu = smp_processor_id(); ASSERT(!in_atomic()); @@ -1099,7 +1100,7 @@ static void schedule(void) BUG(); } - spin_lock_irq(sd->schedule_lock); + pcpu_schedule_lock_irq(cpu); stop_timer(&sd->s_timer); @@ -1116,7 +1117,7 @@ static void schedule(void) if ( unlikely(prev == next) ) { - spin_unlock_irq(sd->schedule_lock); + pcpu_schedule_unlock_irq(cpu); trace_continue_running(next); return continue_running(prev); } @@ -1154,7 +1155,7 @@ static void schedule(void) ASSERT(!next->is_running); next->is_running = 1; - spin_unlock_irq(sd->schedule_lock); + pcpu_schedule_unlock_irq(cpu); perfc_incr(sched_ctx); -- cgit v1.2.3