[PATCH 11/16] rcu: Check for spurious wakeup using return value

Pranith Kumar
2014-07-23T05:12:38Z

When the gp_kthread wakes up from the wait event, it returns 0 if the wake up is
due to the condition having been met. This commit checks this return value
for a spurious wake up before calling rcu_gp_init().

Signed-off-by: Pranith Kumar <bobby.prani@gmail.com>
---
kernel/rcu/tree.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index f8847d9..3b20ad2 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1790,11 +1790,11 @@ static int __noreturn rcu_gp_kthread(void *arg)
ACCESS_ONCE(rsp->gpnum),
TPS("reqwait"));
rsp->gp_state = RCU_GP_WAIT_GPS;
- wait_event_interruptible(rsp->gp_wq,
+ ret = wait_event_interruptible(rsp->gp_wq,
ACCESS_ONCE(rsp->gp_flags) &
RCU_GP_FLAG_INIT);
/* Locking provides needed memory barrier. */
- if (rcu_gp_init(rsp))
+ if (!ret && rcu_gp_init(rsp))
break;
cond_resched();
flush_signals(current);
--
2.0.0.rc2