From b9832cfe973f23490fdccf392f13597b797eb777 Mon Sep 17 00:00:00 2001 From: Anders Roxell Date: Tue, 27 Nov 2018 10:40:51 +0100 Subject: [PATCH 2/2] kernel/trace: fix watchdog soft lockup When building a allmodconfig kernel for arm64 and boot that in qemu, CONFIG_FTRACE_STARTUP_TEST gets enabled and that takes time so the watchdog expires and prints out a message like this: 'watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:1]' Each time the function ftrace_replace_code gets called it stays in that functions loop for 41424 times. Rework so that function cond_resched() gets called in the ftrace_replace_code loop. Co-developed-by: Arnd Bergmann Signed-off-by: Arnd Bergmann Signed-off-by: Anders Roxell --- kernel/trace/ftrace.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 5b4f73e4fd56..3f456921dedf 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2426,6 +2426,10 @@ void __weak ftrace_replace_code(int enable) do_for_each_ftrace_rec(pg, rec) { + /* This loop can take minutes when sanitizers are enabled, so + * lets make sure we allow RCU processing. + */ + cond_resched(); if (rec->flags & FTRACE_FL_DISABLED) continue; -- 2.19.2