On Tue, Apr 28, 2015 at 12:42 PM, Sudeep Holla <sudeep.holla@xxxxxxx> wrote: > > > On 28/04/15 11:34, Daniel Lezcano wrote: >> >> On 04/28/2015 12:11 PM, Linus Walleij wrote: >>> >>> On Thu, Apr 2, 2015 at 12:22 AM, Rafael J. Wysocki >>> <rjw@xxxxxxxxxxxxx> wrote: >>> >>>> From: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >>>> >>>> Replace the clockevents_notify() call with an explicit function >>>> call. >>>> >>>> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx> >>>> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> >>> >>> >>> For some reason this makes my Ux500 system arbitrarily hang, >>> especially during boot. Bisected down to this commit. Since the >>> entire changeset is removing the notifications altogether I can't >>> just revert it. >>> >>> Disabling CONFIG_CPU_IDLE removes the problem. >>> >>> Tried registering a stub driver (I just #if 0 all the code in >>> drivers/cpuidle/cpuidle-ux500.c) it still crashes. >>> >>> That makes me think something inside the cpuidle subsystem is >>> locking up after this, but my other idea is that the timer may be >>> involved in some way, like this is stressing the timer in some new >>> yet untested way. >>> >>> Has anyone else seen problems with this or is it only ux500? >>> >>> I'm looking closer at it but feel a bit clueless... >> >> >> If you keep the #if 0 and remove the CPUIDLE_FLAG_TIMER_STOP flag, >> does it still crash ? >> > > At-least I observed issue only when I am using hardware broadcast timer. > It doesn't hang when I am using hrtimer as broadcast timer in which case > one of the cpu will be not enter deeper idle states that lose timer. > I will rerun on v4.1-rc1 and post the complete log. So the bug here is that cpuidle_enter() enables interrupts, so the assumption about them being not enabled made by tick_broadcast_oneshot_control() is actually not valid. It looks like we need to acquire the clockevents_lock at least in this particular case. Let me see where to put it and I'll send a patch for testing. Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
