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From: Christoph Hellwig <hch@lst.de>
To: Hillf Danton <hdanton@sina.com>
Cc: Sven Schnelle <svens@linux.ibm.com>,
	Josef Bacik <josef@toxicpanda.com>,
	Christoph Hellwig <hch@lst.de>, Jens Axboe <axboe@kernel.dk>,
	linux-block@vger.kernel.org, nbd@other.debian.org,
	linux-kernel@vger.kernel.org
Subject: Re: WARNING: possible circular locking dependency detected in nbd
Date: Fri, 20 Aug 2021 12:02:02 +0200	[thread overview]
Message-ID: <20210820100202.GB9872@lst.de> (raw)
In-Reply-To: <20210819072938.3839-1-hdanton@sina.com>

On Thu, Aug 19, 2021 at 03:29:38PM +0800, Hillf Danton wrote:
> On Wed, 18 Aug 2021 09:10:49 +0200 Sven Schnelle wrote:
> > Hi,
> > 
> > i'm seeing the lockdep splat below in CI. I think this is because
> 
> Thanks for reporting it.
> 
> > nbd_open is called with disk->open_mutex held, and acquires
> > nbd_index_mutex. However, nbd_put() first takes the nbd_index_lock,
> > and calls del_gendisk, which locks disk->open_mutex, so the order is
> > reversed.
> 
> Right. See diff attached.

This is already fixed in linux-next.

      parent reply	other threads:[~2021-08-20 10:02 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-18  7:10 WARNING: possible circular locking dependency detected in nbd Sven Schnelle
     [not found] ` <20210819072938.3839-1-hdanton@sina.com>
2021-08-20 10:02   ` Christoph Hellwig [this message]

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