From: Peter Zijlstra peterz@infradead.org
[ Upstream commit d2098b4440981705e844c50254540ba7b5f82795 ]
Kim reported that perf-ftrace made his box unhappy. It turns out that commit:
ff5c4f5cad33 ("rcu/tree: Mark the idle relevant functions noinstr")
removed one too many notrace qualifiers, probably due to there not being a helpful comment.
This commit therefore reinstates the notrace and adds a comment to avoid losing it again.
[ paulmck: Apply Steven Rostedt's feedback on the comment. ] Fixes: ff5c4f5cad33 ("rcu/tree: Mark the idle relevant functions noinstr") Reported-by: Kim Phillips kim.phillips@amd.com Signed-off-by: Peter Zijlstra (Intel) peterz@infradead.org Signed-off-by: Paul E. McKenney paulmck@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- kernel/rcu/tree.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 655ade095e043..585bf112ee08d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1093,8 +1093,11 @@ static void rcu_disable_urgency_upon_qs(struct rcu_data *rdp) * CPU can safely enter RCU read-side critical sections. In other words, * if the current CPU is not in its idle loop or is in an interrupt or * NMI handler, return true. + * + * Make notrace because it can be called by the internal functions of + * ftrace, and making this notrace removes unnecessary recursion calls. */ -bool rcu_is_watching(void) +notrace bool rcu_is_watching(void) { bool ret;