Messages in this thread | | | Date | Sun, 23 Nov 2014 19:21:08 +0100 | From | Oleg Nesterov <> | Subject | Re: task_stat splat |
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Damn, sorry for noise ;)
On 11/23, Oleg Nesterov wrote: > > On 11/23, Oleg Nesterov wrote: > > > > On 11/23, Oleg Nesterov wrote: > > > > > > On 11/23, Borislav Petkov wrote: > > > > > > > > where we end up with a zero PMD. RIP is corrupted too so we're somewhere > > > > off in the fields. > > > > > > PMD = 0 is fine I guess, addr == 0 is not mapped. > > > > > > > Comment over thread_group_cputime() talks about dead tasks accounting > > > > > > This comment simply means that we also need to read the accumulated > > > counters in tsk->signal. > > > > > > > which might be relevant as we're seeing not mapped page hierarchy so > > > > something must have gone away recently but we try to look at it. > > > > > > This is called under ->siglock, we can't race with exit/etc. But this > > > doesn't matter, it is not that we (say) get t == NULL or something like > > > this. > > > > > > RIP == 0, and this looks "impossible", I do not see indirect function > > > calls in this paths. > > > > Ah, I didn't notice you mentioned tip/master... so it looks as if > > sched_class->update_curr is NULL? > > Perhaps this is migration thread? stop_sched_class doesn't have ->update_curr.
Yes, I think this can explain the problem, but
> could you try to cat /proc/pid-of-migration-thread/stat on your machine?
This won't trigger the crash unless it is running.
Oleg.
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