The following commit has been merged into the core/rcu branch of tip: Commit-ID: d2098b4440981705e844c50254540ba7b5f82795 Gitweb: https://git.kernel.org/tip/d2098b4440981705e844c50254540ba7b5f82795 Author: Peter Zijlstra <peterz@xxxxxxxxxxxxx> AuthorDate: Tue, 29 Sep 2020 13:33:40 +02:00 Committer: Paul E. McKenney <paulmck@xxxxxxxxxx> CommitterDate: Thu, 19 Nov 2020 19:37:17 -08:00 rcu,ftrace: Fix ftrace recursion 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@xxxxxxx> Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx> Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx> --- 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 5f458e4..d6a015e 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;
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