From: Oleg Nesterov <oleg@redhat.com>
To: "Kohli, Gaurav" <gkohli@codeaurora.org>
Cc: Qian Cai <cai@lca.pw>, Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
linux kernel <linux-kernel@vger.kernel.org>
Subject: Re: kernel BUG at kernel/sched/core.c:3490!
Date: Wed, 16 Jan 2019 18:32:30 +0100 [thread overview]
Message-ID: <20190116173229.GA20060@redhat.com> (raw)
In-Reply-To: <5a65a014-9013-cfbd-48a9-67199d33e719@codeaurora.org>
On 01/12, Kohli, Gaurav wrote:
>
> HI Peter, Oleg,
>
> as per flag and state this seems to be possible only from below code:
Not sure I understand you,
> XXX: 0 1 0x40844c
> PF_NOFREEZE
> PF_RANDOMIZE
> PF_SIGNALED
> PF_FORKNOEXEC
> PF_EXITING
> PF_EXITPIDONE
>
> above state shows do_exit runs properely and if somehow after parked stated
> , TASK_WAKEKILL got set and signal_pending_state returns 1 in below case:
>
> switch_count = &prev->nivcsw;
> if (!preempt && prev->state) {
> if (unlikely(signal_pending_state(prev->state, prev))) {
> prev->state = TASK_RUNNING;
> } else {
> deactivate_task(rq, prev, DEQUEUE_SLEEP |
> DEQUEUE_NOCLOCK);
or task->state was TASK_RUNNING when __schedule() was called, or the deactivated
dead task was woken up later...
The only problem is that every case looks "obviously impossible" ;) I have no
idea whats going on, I can only suggest more stupid debugging patches which might
narrow the problem.
Oleg.
prev parent reply other threads:[~2019-01-16 17:32 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-01 5:44 kernel BUG at kernel/sched/core.c:3490! Qian Cai
2019-01-07 13:52 ` Peter Zijlstra
2019-01-07 14:36 ` Qian Cai
2019-01-07 17:56 ` Oleg Nesterov
2019-01-11 10:37 ` Kohli, Gaurav
2019-01-11 16:17 ` Qian Cai
2019-01-12 8:54 ` Kohli, Gaurav
2019-01-16 17:32 ` Oleg Nesterov [this message]
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