Messages in this thread | | | Date | Sun, 23 Nov 2014 18:22:56 +0100 | From | Oleg Nesterov <> | Subject | Re: task_stat splat |
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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.
> [42460.389625] Call Trace: > [42460.389635] [<ffffffff810813d9>] ? task_sched_runtime+0x99/0xc0 > [42460.389643] [<ffffffff81088b5c>] thread_group_cputime+0x17c/0x2d0
Could you identify somehow the line which matches task_sched_runtime+0x99 ? Probably do_task_delta_exec()...
Oleg.
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