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Date:   Tue, 30 Nov 2021 04:57:31 -0800
From:   Christoph Hellwig <hch@infradead.org>
To:     Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc:     Christoph Hellwig <hch@infradead.org>, Jan Kara <jack@suse.cz>,
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Subject: Re: [syzbot] possible deadlock in blkdev_put (2)
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On Mon, Nov 29, 2021 at 07:36:27PM +0900, Tetsuo Handa wrote:
> If the caller just want to call ioctl(LOOP_CTL_GET_FREE) followed by
> ioctl(LOOP_CONFIGURE), deferring __loop_clr_fd() would be fine.
> 
> But the caller might want to unmount as soon as fput(filp) from __loop_clr_fd() completes.
> I think we need to wait for __loop_clr_fd() from lo_release() to complete.

Anything else could have a reference to this or other files as well.
So I can't see how deferring the clear to a different context can be
any kind of problem in practice.