linux-kernel - Re: [BUG] Infinite loop in cleanup_mnt() task

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Date: Fri, 9 Feb 2024 20:13:49 -0800
From: Calvin Owens <jcalvinowens@...il.com>
To: Al Viro <viro@...iv.linux.org.uk>
Cc: Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [BUG] Infinite loop in cleanup_mnt() task_work on 6.3-rc3

On Tuesday 02/06 at 20:50 +0000, Al Viro wrote:
> On Tue, Feb 06, 2024 at 11:52:58AM -0800, Calvin Owens wrote:
> > Hello all,
> >
> > A couple times in the past week, my laptop has been wedged by a spinning
> > cleanup_mnt() task_work from an exiting container runtime (bwrap).
>
> Check if git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs.git #fixes
>
> helps.

That absolutely fixes it (the revert of 57851607).

This reproducer hits the bug 100% of the time on my Debian Sid GNOME box:

	$ for i in {1..1000}; do \
		dd if=/dev/urandom bs=65536 count=1 status=none | \
		convert -size 256x256 -depth 8 GRAY:- ${i}.png; done
	$ nautilus .

It turns out Nautilus was the trigger: it spawns and destroys containers
in very quick succession to compute each thumbnail in a directory of
images.

Thanks,
Calvin