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From: Ming Lei <ming.lei@redhat.com>
To: Christoph Hellwig <hch@lst.de>
Cc: Dusty Mabe <dusty@dustymabe.com>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-raid@vger.kernel.org, ming.lei@redhat.com
Subject: Re: regression caused by block: freeze the queue earlier in del_gendisk
Date: Tue, 13 Sep 2022 09:55:57 +0800	[thread overview]
Message-ID: <Yx/jLTknQm9VeHi4@T590> (raw)
In-Reply-To: <20220912071618.GA4971@lst.de>

On Mon, Sep 12, 2022 at 09:16:18AM +0200, Christoph Hellwig wrote:
> On Fri, Sep 09, 2022 at 04:24:40PM +0800, Ming Lei wrote:
> > On Wed, Sep 07, 2022 at 09:33:24AM +0200, Christoph Hellwig wrote:
> > > On Thu, Sep 01, 2022 at 03:06:08PM +0800, Ming Lei wrote:
> > > > It is a bit hard to associate the above commit with reported issue.
> > > 
> > > So the messages clearly are about something trying to open a device
> > > that went away at the block layer, but somehow does not get removed
> > > in time by udev (which seems to be a userspace bug in CoreOS).  But
> > > even with that we really should not hang.
> > 
> > Xiao Ni provides one script[1] which can reproduce the issue more or less.
> 
> I've run the reproduced 10000 times on current mainline, and while
> it prints one of the autoloading messages per run, I've not actually
> seen any kind of hang.

I can't reproduce the hang too.

What I meant is that new raid disk can be added by mdadm after stopping
the imsm container and raid disk with the autoloading messages printed,
I understand this behavior isn't correct, but I am not familiar with
raid enough.

It might be related with the delay deleting gendisk from wq & md kobj
release handler.

During reboot, if mdadm does this stupid thing without stopping, the hang
could be caused.

I think the root cause is that why mdadm tries to open/add new raid bdev
crazily during reboot.


Thanks, 
Ming


  reply	other threads:[~2022-09-13  1:56 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-26 16:15 regression caused by block: freeze the queue earlier in del_gendisk Dusty Mabe
2022-08-28 10:24 ` Thorsten Leemhuis
2022-08-31 12:36   ` Thorsten Leemhuis
2022-09-01  7:06 ` Ming Lei
2022-09-03 13:47   ` Dusty Mabe
2022-09-07  7:33   ` Christoph Hellwig
2022-09-07  8:38     ` Ming Lei
2022-09-07 14:40       ` Chaitanya Kulkarni
2022-09-07 14:58         ` Ming Lei
2022-09-07 15:53           ` Chaitanya Kulkarni
2022-09-09  8:24     ` Ming Lei
2022-09-12  7:16       ` Christoph Hellwig
2022-09-13  1:55         ` Ming Lei [this message]
2022-09-13  2:36           ` Dusty Mabe
2022-09-20  9:11             ` Thorsten Leemhuis
2022-09-20 14:05               ` Jens Axboe
2022-09-20 14:12                 ` Christoph Hellwig
2022-09-20 14:14                   ` Jens Axboe
2022-09-21  9:25                     ` Thorsten Leemhuis
2022-09-21 14:34                       ` Jens Axboe
2022-09-21 14:47                         ` Greg KH
2022-09-21 14:56                           ` Jens Axboe
2022-09-26  7:09                             ` Greg KH
2022-09-07  7:22 ` Christoph Hellwig
2022-09-07 14:56   ` Dusty Mabe

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