322c4293ec
syzbot is reporting circular locking problem at __loop_clr_fd() [1], for
commit 87579e9b7d8dc36e ("loop: use worker per cgroup instead of kworker")
is calling destroy_workqueue() with disk->open_mutex held.
This circular dependency cannot be broken unless we call __loop_clr_fd()
without holding disk->open_mutex. Therefore, defer __loop_clr_fd() from
lo_release() to a WQ context.
Link: https://syzkaller.appspot.com/bug?extid=643e4ce4b6ad1347d372 [1]
Reported-by: syzbot <syzbot+643e4ce4b6ad1347d372@syzkaller.appspotmail.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Cc: Jan Kara <jack@suse.cz>
Tested-by: syzbot+643e4ce4b6ad1347d372@syzkaller.appspotmail.com
Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/1ed7df28-ebd6-71fb-70e5-1c2972e05ddb@i-love.sakura.ne.jp
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.