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From: Amir Goldstein <>
To: Dmitry Vyukov <>
	Miklos Szeredi <>,
	linux-fsdevel <>,
	linux-kernel <>,
	overlayfs <>,
Subject: Re: possible deadlock in ovl_write_iter
Date: Tue, 27 Nov 2018 18:13:03 +0200	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

> > This looks like a false positive because lockdep is not aware of
> > s_stack_depth of the file (fs) associated with the pipe.
> There must be some annotation to tell lockdep about this.

It's a long story that can be summed up as "not simple":

Overlayfs annotates inode mutex in lockdep friendly manner.
This is why you see:
 (&ovl_i_mutex_key[depth]){+.+.}, at: inode_lock

But this does not extend to other locks that may be associated
with filesystem or blockdev objects (e.g. pipe_lock()) and does
not cover the case of stacked blockdev (e.g. loop).


      reply	other threads:[~2018-11-28  3:11 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
     [not found] ` <>
2018-09-27  3:51   ` possible deadlock in ovl_write_iter Amir Goldstein
2018-11-27  7:06 ` syzbot
2018-11-27  7:44   ` Amir Goldstein
2018-11-27 14:12     ` Dmitry Vyukov
2018-11-27 15:07   ` Amir Goldstein
2018-11-27 15:48     ` Dmitry Vyukov
2018-11-27 16:13       ` Amir Goldstein [this message]

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