On Tue, 30 Apr 2013, Dave Jones wrote:
> On Tue, Apr 30, 2013 at 05:20:07PM -0400, Dave Jones wrote:
> > I have a machine that crashes instantly on boot up on Linus'
> > post-3.9 tree. (8c55f1463c1fd318d5e785f02b80bcc32176d342)
> >
> > By booting with boot_delay=100, I was able to take a photo
> > and capture the top of the trace. (For some reason, larger boot
> > delay parameters seem to make it take forever before printing
> > even a single character, which made this a pain to debug).
> >
> > The WARN_ON it prints right before locking up is this in
> clockevents_program_event
> >
> > 208 if (unlikely(expires.tv64 < 0)) {
> > 209 WARN_ON_ONCE(1);
> > 210 return -ETIME;
> > 211 }
> >
> > booting with maxcpus=1 avoids the problem.
> >
> > I'm still trying to get a complete stack trace, though it's painful
> > due to the above reason.
>
> On a second machine, I'm seeing an oops even earlier. As soon as I
> exit grub, I get a blinking cursor. If I boot with earlyprintk=vga
> I can see..
>
> Call Trace:
> <IRQ>
> tick_check_oneshot_broadcast
> tick_check_idle
> irq_enter
> do_IRQ
> common_interrupt
> <EOI>
> x86_64_start_reservations
> x86_64_start_kernel
> RIP: clockevents_set_mode+0x18
>
> Matching up the Code: line of the trace with the disassembly I see..
>
> if (dev->mode != mode) {
> 4c8: 39 77 38 cmp %esi,0x38(%rdi)
>
>
> the comment above that code is telling..
>
> /*
> * Must be called with interrupts disabled !
> */
>
> So how did we get an IRQ ?
Well, we are inside an IRQ and the code is called with interrupts
disabled from there. Fix below.
Thanks,
tglx
diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c
index 61d00a8..db9da73 100644
--- a/kernel/time/tick-broadcast.c
+++ b/kernel/time/tick-broadcast.c
@@ -475,7 +475,8 @@ void tick_check_oneshot_broadcast(int cpu)
if (cpumask_test_cpu(cpu, tick_broadcast_oneshot_mask)) {
struct tick_device *td = &per_cpu(tick_cpu_device, cpu);
- clockevents_set_mode(td->evtdev, CLOCK_EVT_MODE_ONESHOT);
+ if (td)
+ clockevents_set_mode(td->evtdev,
CLOCK_EVT_MODE_ONESHOT);
}
}
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