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From: Al Viro <viro@zeniv.linux.org.uk>
To: Christoph Hellwig <hch@lst.de>
Cc: Amir Goldstein <amir73il@gmail.com>,
	syzbot <syzbot+9a5b0ced8b1bfb238b56@syzkaller.appspotmail.com>,
	gregkh@linuxfoundation.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
	tj@kernel.org, valesini@yandex-team.ru,
	Christian Brauner <brauner@kernel.org>, Jan Kara <jack@suse.cz>,
	Miklos Szeredi <miklos@szeredi.hu>
Subject: Re: [syzbot] [kernfs?] possible deadlock in kernfs_fop_llseek
Date: Sat, 6 Apr 2024 04:54:51 +0100	[thread overview]
Message-ID: <20240406035451.GW538574@ZenIV> (raw)
In-Reply-To: <20240405065135.GA3959@lst.de>

On Fri, Apr 05, 2024 at 08:51:35AM +0200, Christoph Hellwig wrote:
> On Thu, Apr 04, 2024 at 12:33:40PM +0300, Amir Goldstein wrote:
> > I don't follow what you are saying.
> > Which code is in non-starter violation?
> > kernfs for calling lookup_bdev() with internal of->mutex held?
> 
> That is a huge problem, and has been causing endless annoying lockdep
> chains in the block layer for us.  If we have some way to kill this
> the whole block layer would benefit.

Specifically of->mutex or having pathwalk done from some ->write_iter()?

Incidentally, losetup happily accepts sysfs files as backing store.
I don't think it adds problems we don't have otherwise, but IMO
that's really bogus...

  parent reply	other threads:[~2024-04-06  3:54 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2024-04-03 18:23 [syzbot] [kernfs?] possible deadlock in kernfs_fop_llseek syzbot
2024-04-03 23:51 ` syzbot
2024-04-04  6:54   ` Amir Goldstein
2024-04-04  8:11     ` Al Viro
2024-04-04  8:21       ` Al Viro
2024-04-04  8:40         ` Al Viro
2024-04-04  9:33         ` Amir Goldstein
2024-04-04 22:01           ` Al Viro
2024-04-05 10:34             ` Amir Goldstein
2024-04-05  6:51           ` Christoph Hellwig
2024-04-05 11:19             ` Christian Brauner
2024-04-05 13:48               ` Christian Brauner
2024-04-05 14:52                 ` Christoph Hellwig
2024-04-05 15:41             ` Tejun Heo
2024-04-06  3:54             ` Al Viro [this message]
2024-04-05 10:47           ` Christian Brauner
2024-04-05 14:48             ` Amir Goldstein
2024-04-06  4:09           ` Al Viro
2024-04-06  5:25             ` Amir Goldstein
2024-04-05 15:08     ` Amir Goldstein
2024-04-05 15:37       ` syzbot
2024-04-05 16:23         ` Al Viro
2024-04-06  5:34           ` Amir Goldstein
2024-04-06  7:05             ` syzbot
2024-04-06  7:11               ` Al Viro
2024-04-06  8:57                 ` Amir Goldstein
2024-04-07  0:50                   ` Al Viro
2024-04-07 11:02                     ` Amir Goldstein
2024-04-09  9:18                     ` Christian Brauner

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