From: Jens Axboe <axboe@kernel.dk>
To: Qian Cai <cai@lca.pw>
Cc: akpm@linux-foundation.org, hch@lst.de, peterz@infradead.org,
oleg@redhat.com, gkohli@codeaurora.org, mingo@redhat.com,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: fix a crash in do_task_dead()
Date: Wed, 29 May 2019 14:31:58 -0600 [thread overview]
Message-ID: <ad24b8de-c1dc-f52a-06af-103ceda891a6@kernel.dk> (raw)
In-Reply-To: <1559161526-618-1-git-send-email-cai@lca.pw>
On 5/29/19 2:25 PM, Qian Cai wrote:
> The commit 0619317ff8ba ("block: add polled wakeup task helper")
> replaced wake_up_process() with blk_wake_io_task() in
> end_swap_bio_read() which triggers a crash when running heavy swapping
> workloads.
>
> [T114538] kernel BUG at kernel/sched/core.c:3462!
> [T114538] Process oom01 (pid: 114538, stack limit = 0x000000004f40e0c1)
> [T114538] Call trace:
> [T114538] do_task_dead+0xf0/0xf8
> [T114538] do_exit+0xd5c/0x10fc
> [T114538] do_group_exit+0xf4/0x110
> [T114538] get_signal+0x280/0xdd8
> [T114538] do_notify_resume+0x720/0x968
> [T114538] work_pending+0x8/0x10
>
> This is because shortly after set_special_state(TASK_DEAD),
> end_swap_bio_read() is called from an interrupt handler that revive the
> task state to TASK_RUNNING causes __schedule() to return and trip the
> BUG() later.
>
> [ C206] Call trace:
> [ C206] dump_backtrace+0x0/0x268
> [ C206] show_stack+0x20/0x2c
> [ C206] dump_stack+0xb4/0x108
> [ C206] blk_wake_io_task+0x7c/0x80
> [ C206] end_swap_bio_read+0x22c/0x31c
> [ C206] bio_endio+0x3d8/0x414
> [ C206] dec_pending+0x280/0x378 [dm_mod]
> [ C206] clone_endio+0x128/0x2ac [dm_mod]
> [ C206] bio_endio+0x3d8/0x414
> [ C206] blk_update_request+0x3ac/0x924
> [ C206] scsi_end_request+0x54/0x350
> [ C206] scsi_io_completion+0xf0/0x6f4
> [ C206] scsi_finish_command+0x214/0x228
> [ C206] scsi_softirq_done+0x170/0x1a4
> [ C206] blk_done_softirq+0x100/0x194
> [ C206] __do_softirq+0x350/0x790
> [ C206] irq_exit+0x200/0x26c
> [ C206] handle_IPI+0x2e8/0x514
> [ C206] gic_handle_irq+0x224/0x228
> [ C206] el1_irq+0xb8/0x140
> [ C206] _raw_spin_unlock_irqrestore+0x3c/0x74
> [ C206] do_task_dead+0x88/0xf8
> [ C206] do_exit+0xd5c/0x10fc
> [ C206] do_group_exit+0xf4/0x110
> [ C206] get_signal+0x280/0xdd8
> [ C206] do_notify_resume+0x720/0x968
> [ C206] work_pending+0x8/0x10
>
> Before the offensive commit, wake_up_process() will prevent this from
> happening by taking the pi_lock and bail out immediately if TASK_DEAD is
> set.
>
> if (!(p->state & TASK_NORMAL))
> goto out;
>
> Fix it by calling wake_up_process() if it is in a non-task context.
I like this one a lot better than the previous fix. Unless folks
object, I'll queue this up for 5.2, thanks.
--
Jens Axboe
next prev parent reply other threads:[~2019-05-29 20:32 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-05-29 20:25 Qian Cai
2019-05-29 20:31 ` Jens Axboe [this message]
2019-05-30 8:03 ` Peter Zijlstra
2019-05-31 21:12 ` Jens Axboe
2019-06-03 12:37 ` Peter Zijlstra
2019-06-03 12:44 ` Peter Zijlstra
2019-06-03 16:09 ` Oleg Nesterov
2019-06-03 16:19 ` Peter Zijlstra
2019-06-03 16:23 ` Jens Axboe
2019-06-05 15:04 ` Jens Axboe
2019-06-07 13:35 ` Peter Zijlstra
2019-06-07 14:23 ` Peter Zijlstra
2019-06-08 8:39 ` Jens Axboe
2019-06-10 13:13 ` Gaurav Kohli
2019-06-10 14:46 ` Oleg Nesterov
2019-06-11 4:39 ` Gaurav Kohli
2019-06-30 23:06 ` Hugh Dickins
2019-07-01 14:22 ` Jens Axboe
2019-07-02 22:06 ` Andrew Morton
2019-07-03 17:35 ` Oleg Nesterov
2019-07-03 17:44 ` Hugh Dickins
2019-07-04 16:00 ` Oleg Nesterov
2019-07-03 17:52 ` Jens Axboe
2019-05-30 11:15 ` Oleg Nesterov
2019-05-31 21:10 ` Jens Axboe
2019-07-04 16:03 ` [PATCH] swap_readpage: avoid blk_wake_io_task() if !synchronous Oleg Nesterov
2019-07-04 19:32 ` Andrew Morton
2019-07-04 21:15 ` Hugh Dickins
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