On 06/24, Dave Jones wrote: > > On Sun, Jun 23, 2013 at 06:04:52PM +0200, Oleg Nesterov wrote: > > > > Could you please do the following: > > > > 1. # cd /sys/kernel/debug/tracing > > # echo 0 >> options/function-trace > > # echo preemptirqsoff >> current_tracer > > > > 2. reproduce the lockup again > > > > 3. show the result of > > # cat trace > > Not sure this is helpful, but..
This makes me think that something is seriously broken. Or I do not understand this stuff at all. Quite possible too. Steven, could you please help? > # preemptirqsoff latency trace v1.1.5 on 3.10.0-rc7+ > # -------------------------------------------------------------------- > # latency: 165015310 us, #4/4, CPU#1 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:4) OK, 165015310/1000000 = 165, nice. > # ----------------- > # | task: trinity-child1-3173 (uid:1000 nice:19 policy:0 rt_prio:0) > # ----------------- > # => started at: vprintk_emit > # => ended at: vprintk_emit > # > # > # _------=> CPU# > # / _-----=> irqs-off > # | / _----=> need-resched > # || / _---=> hardirq/softirq > # ||| / _--=> preempt-depth > # |||| / delay > # cmd pid ||||| time | caller > # \ / ||||| \ | / > trinity--3173 1dNh1 0us!: console_unlock <-vprintk_emit > trinity--3173 1dNh1 165015310us : console_unlock <-vprintk_emit > trinity--3173 1dNh1 165015311us+: stop_critical_timings <-vprintk_emit > trinity--3173 1dNh1 165015315us : <stack trace> > => console_unlock > => vprintk_emit > => printk > => watchdog_timer_fn But this is already called in the non-preemtible context, how can 'started at' blame vprintk_emit? > => __run_hrtimer > => hrtimer_interrupt > => smp_apic_timer_interrupt > => apic_timer_interrupt > => _raw_spin_lock This is where start_critical_timing() should be called? Or by TRACE_IRQS_OFF in apic_timer_interrupt... > => sync_inodes_sb > => sync_inodes_one_sb > => iterate_supers > => sys_sync > => tracesys Also. watchdog_timer_fn() calls printk() only if it detects the lockup, so I assume you hit another one? Oleg. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
