From: Christoph Hellwig <hch@lst.de>
To: Dave Chinner <david@fromorbit.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
Stephen Boyd <sboyd@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
syzbot <syzbot+d6c75f383e01426a40b4@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
syzkaller-bugs@googlegroups.com, Waiman Long <llong@redhat.com>,
"Paul E. McKenney" <paulmck@kernel.org>,
Al Viro <viro@zeniv.linux.org.uk>, Jens Axboe <axboe@kernel.dk>,
linux-block@vger.kernel.org, linux-fsdevel@vger.kernel.org,
hch@lst.de
Subject: Re: [syzbot] WARNING in __init_work
Date: Mon, 20 Sep 2021 14:28:46 +0200 [thread overview]
Message-ID: <20210920122846.GA16661@lst.de> (raw)
In-Reply-To: <20210920040336.GV2361455@dread.disaster.area>
On Mon, Sep 20, 2021 at 02:03:36PM +1000, Dave Chinner wrote:
> > >> > bdi_remove_from_list mm/backing-dev.c:938 [inline]
> > >> > bdi_unregister+0x177/0x5a0 mm/backing-dev.c:946
> > >> > release_bdi+0xa1/0xc0 mm/backing-dev.c:968
> > >> > kref_put include/linux/kref.h:65 [inline]
> > >> > bdi_put+0x72/0xa0 mm/backing-dev.c:976
> > >> > bdev_free_inode+0x116/0x220 fs/block_dev.c:819
> > >> > i_callback+0x3f/0x70 fs/inode.c:224
> >
> > The inode code uses RCU for freeing an inode object which then ends up
> > calling bdi_put() and subsequently in synchronize_rcu_expedited().
>
> Commit 889c05cc5834 ("block: ensure the bdi is freed after
> inode_detach_wb") might be a good place to start looking here. It
> moved the release of the bdi from ->evict context to the RCU freeing
> of the blockdev inode...
Well, the block code already does a bdi_unregister in del_gendisk.
So if we end up freeing the whole device bdev with a registered bdi
something is badly going wrong. Unfortunately the log in this report
isn't much help on how we got there. IIRC syzbot will eventually spew
out a reproducer, so it might be worth to wait for that.
next prev parent reply other threads:[~2021-09-20 12:28 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-15 17:00 [syzbot] WARNING in __init_work syzbot
2021-09-15 23:14 ` Andrew Morton
2021-09-16 2:29 ` Stephen Boyd
2021-09-19 12:41 ` Thomas Gleixner
2021-09-20 4:03 ` Dave Chinner
2021-09-20 12:28 ` Christoph Hellwig [this message]
2021-09-20 12:38 ` Paul E. McKenney
2021-09-20 12:45 ` Christoph Hellwig
2021-09-20 12:54 ` Paul E. McKenney
2021-09-21 18:38 ` Stephen Boyd
2021-09-21 20:19 ` Thomas Gleixner
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20210920122846.GA16661@lst.de \
--to=hch@lst.de \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=david@fromorbit.com \
--cc=linux-block@vger.kernel.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=llong@redhat.com \
--cc=paulmck@kernel.org \
--cc=sboyd@kernel.org \
--cc=syzbot+d6c75f383e01426a40b4@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--cc=tglx@linutronix.de \
--cc=viro@zeniv.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).