On Wed, 28 Nov 2018 09:13:34 +0100 Anders Roxell <[email protected]> wrote:
> 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 <[email protected]> > Signed-off-by: Arnd Bergmann <[email protected]> > Signed-off-by: Anders Roxell <[email protected]> > --- > 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; > NACK. On some architectures this code is run from stop machine. We can't call cond_resched() because it may be called with interrupts disabled. This is a weak function. If arm64 has special needs, just copy it in the arm64 code. -- Steve
