* Frederic Weisbecker <[email protected]> wrote:
> On Mon, Apr 24, 2017 at 04:45:23PM +0200, Ingo Molnar wrote:
> >
> > * Frederic Weisbecker <[email protected]> wrote:
> >
> > > On Mon, Apr 24, 2017 at 10:08:35AM +0200, Ingo Molnar wrote:
> > > >
> > > > * Frederic Weisbecker <[email protected]> wrote:
> > > >
> > > > > As suggested by Thomas Gleixner, the second patch now integrates
> > > > > a fix in case the sanity check fails and the clockevent isn't
> > > > > programmed
> > > > > as expected.
> > > > >
> > > > > Frederic Weisbecker (2):
> > > > > nohz: Fix again collision between tick and other hrtimers
> > > > > tick: Make sure tick timer is active when bypassing reprogramming
> > > > >
> > > > > kernel/time/tick-sched.c | 33 ++++++++++++++++++++++++++++++---
> > > > > kernel/time/tick-sched.h | 2 ++
> > > > > 2 files changed, 32 insertions(+), 3 deletions(-)
> > > >
> > > > So I think one of these is causing a new warning on latest -tip:
> > > >
> > > > [ 333.341756] ------------[ cut here ]------------
> > > > [ 333.346404] WARNING: CPU: 0 PID: 0 at kernel/time/tick-sched.c:874
> > > > __tick_nohz_idle_enter+0x461/0x490
> > >
> > > Oh I'll never be done with that bug :)
> > >
> > > Ok I just booted your config with tip/master and didn't see the warning.
> > > But the boot seem to be stalled some time after mounting the root fs.
> > >
> > > Can you please try the following patch and tell me what it returns to you?
> > >
> > > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c
> > > index c47d135..6d72e8b 100644
> > > --- a/kernel/time/tick-sched.c
> > > +++ b/kernel/time/tick-sched.c
> > > @@ -872,6 +872,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct
> > > tick_sched *ts,
> > > goto out;
> > >
> > > WARN_ON_ONCE(1);
> > > + printk_once("basemono: %llu ts->next_tick: %llu
> > > dev->next_event: %llu\n", basemono, ts->next_tick, dev->next_event);
> > > }
> > >
> >
> > Here's what it prints:
> >
> > [ 707.251791] basemono: 706016000000 ts->next_tick: 693216000000
> > dev->next_event: 706016406127
>
> So weird...
>
> Ok I'm going to need serious traces. Can you please add this boot option?
>
> trace_event=hrtimer_cancel,hrtimer_start,hrtimer_expire_entry
Sorry, don't have the time for extensive traces this close to the merge window
-
but are you sure you cannot reproduce it?
The warning popped up on all 3 test systems I tried (two Intel servers, one AMD
server), and it also hit Mike's server - with a fairly regular distro-ish
config.
Thanks,
Ingo
