From d0b24b4e91fcb8408c4979888547f86be514e337 Mon Sep 17 00:00:00 2001 From: "Guilherme G. Piccoli" Date: Tue, 15 Nov 2022 17:48:47 -0300 Subject: ftrace: Prevent RCU stall on PREEMPT_VOLUNTARY kernels The function match_records() may take a while due to a large number of string comparisons, so when in PREEMPT_VOLUNTARY kernels we could face RCU stalls due to that. Add a cond_resched() to prevent that. Link: https://lkml.kernel.org/r/20221115204847.593616-1-gpiccoli@igalia.com Cc: Mark Rutland Suggested-by: Steven Rostedt Acked-by: Paul E. McKenney # from RCU CPU stall warning perspective Signed-off-by: Guilherme G. Piccoli Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 1 + 1 file changed, 1 insertion(+) (limited to 'kernel') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index d04552c0c275..b8e374a372e5 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -4204,6 +4204,7 @@ match_records(struct ftrace_hash *hash, char *func, int len, char *mod) } found = 1; } + cond_resched(); } while_for_each_ftrace_rec(); out_unlock: mutex_unlock(&ftrace_lock); -- cgit v1.2.3