| From | Pranith Kumar <> | Subject | [PATCH 10/16] rcu: Check for RCU_FLAG_GP_INIT bit in gp_flags for spurious wakeup | Date | Wed, 23 Jul 2014 01:09:47 -0400 |
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rcu_gp_init() is called once the gp_kthread wakes up on the condition that the init bit is set in the gp_flags. For a spurious wakeup we need to check that it is actually set. This commit ensures that the RCU_GP_FLAG_INIT bit is set in gp_flags.
Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> --- kernel/rcu/tree.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 8d598a2..f8847d9 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1600,7 +1600,7 @@ static int rcu_gp_init(struct rcu_state *rsp) rcu_bind_gp_kthread(); raw_spin_lock_irq(&rnp->lock); smp_mb__after_unlock_lock(); - if (!ACCESS_ONCE(rsp->gp_flags)) { + if (!(ACCESS_ONCE(rsp->gp_flags) & RCU_GP_FLAG_INIT)) { /* Spurious wakeup, tell caller to go back to sleep. */ raw_spin_unlock_irq(&rnp->lock); return 0; -- 2.0.0.rc2
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