From: Oleg Nesterov <oleg@redhat.com>
To: Borislav Petkov <bp@alien8.de>
Cc: lkml <linux-kernel@vger.kernel.org>,
Rik van Riel <riel@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Steven Rostedt <rostedt@goodmis.org>, x86-ml <x86@kernel.org>
Subject: Re: task_stat splat
Date: Sun, 23 Nov 2014 18:22:56 +0100 [thread overview]
Message-ID: <20141123172256.GA9625@redhat.com> (raw)
In-Reply-To: <20141123111220.GA6436@pd.tnic>
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.
next prev parent reply other threads:[~2014-11-23 17:23 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-11-23 11:12 task_stat splat Borislav Petkov
2014-11-23 17:22 ` Oleg Nesterov [this message]
2014-11-23 17:46 ` Borislav Petkov
2014-11-23 18:26 ` Oleg Nesterov
2014-11-23 17:56 ` Oleg Nesterov
2014-11-23 18:17 ` Oleg Nesterov
2014-11-23 18:21 ` Oleg Nesterov
2014-11-23 18:38 ` Borislav Petkov
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