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From: Keith Busch <kbusch@kernel.org>
To: Bart Van Assche <bvanassche@acm.org>
Cc: syzbot <syzbot+f4353e96f7004ae5a09e@syzkaller.appspotmail.com>,
	axboe@kernel.dk, linux-block@vger.kernel.org,
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	Christoph Hellwig <hch@lst.de>
Subject: Re: [syzbot] [block?] BUG: corrupted list in blk_mq_request_bypass_insert
Date: Mon, 31 Aug 2026 08:58:57 -0600	[thread overview]
Message-ID: <apWWsVUm5ri7b4oR@kbusch-mbp> (raw)
In-Reply-To: <2cf45e85-176a-4209-86ad-8f389a9a4282@acm.org>

On Sat, Aug 29, 2026 at 05:16:00PM -0700, Bart Van Assche wrote:
> On 8/28/26 10:31 PM, syzbot wrote:
> > kernel BUG at lib/list_debug.c:34!
> > Call trace:
> >   __list_add_valid_or_report+0x144/0x148 lib/list_debug.c:32 (P)
> >   __list_add_valid include/linux/list.h:96 [inline]
> >   __list_add include/linux/list.h:158 [inline]
> >   list_add_tail include/linux/list.h:191 [inline]
> >   blk_mq_request_bypass_insert+0x130/0x1cc block/blk-mq.c:2551
> >   blk_mq_requeue_work+0x3a4/0x52c block/blk-mq.c:1560
> >   process_one_work kernel/workqueue.c:3322 [inline]
> >   process_scheduled_works+0x788/0x10b8 kernel/workqueue.c:3405
> >   worker_thread+0x798/0xbd0 kernel/workqueue.c:3486
> >   kthread+0x304/0x3d4 kernel/kthread.c:436
> >   ret_from_fork+0x10/0x20 arch/arm64/kernel/entry.S:838
> 
> If my AI assistant got it right the root cause of this issue is as
> follows (I haven't tried to verify this):
> * Concurrent calls of nvme_reset_work() and blk_mq_requeue_work().
> * nvme_decide_disposition() does not check NVME_REQ_CANCELLED for
>   non-multipath requests and returns RETRY instead of COMPLETE.

We want to be able to retry eligible commands that were caught in the
crossfire of a controller reset.

  reply	other threads:[~2026-08-31 14:58 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-29  5:31 [syzbot] [block?] BUG: corrupted list in blk_mq_request_bypass_insert syzbot
2026-08-30  0:16 ` Bart Van Assche
2026-08-31 14:58   ` Keith Busch [this message]
2026-08-31 20:55     ` Bart Van Assche
2026-09-01 14:49       ` Keith Busch

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