From: Christoph Hellwig <hch@infradead.org>
To: Jens Axboe <axboe@kernel.dk>
Cc: Christoph Hellwig <hch@infradead.org>,
Kees Cook <keescook@chromium.org>,
syzbot+21cfe1f803e0e158acf1@syzkaller.appspotmail.com,
linux-block@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] block: Replace bio_check_ro()'s WARN_ON()
Date: Fri, 22 Nov 2019 11:14:34 -0800 [thread overview]
Message-ID: <20191122191434.GA10150@infradead.org> (raw)
In-Reply-To: <94976fb5-12d3-557d-7f31-347d6116b18c@kernel.dk>
On Fri, Nov 22, 2019 at 12:09:14PM -0700, Jens Axboe wrote:
> On 11/22/19 12:07 PM, Christoph Hellwig wrote:
> > On Fri, Nov 22, 2019 at 10:53:22AM -0800, Kees Cook wrote:
> >> Friendly ping! I keep tripping over this. Can this please get applied so
> >> we can silence syzbot and avoid needless WARNs? :)
> >
> > What call stack reaches this? Upper layers should never submit a write
> > bio on a read-only queue, and we need to fix that in the upper layer.
>
> It's an fsync, the trace is here:
>
> https://syzkaller.appspot.com/x/log.txt?x=159503d2e00000
Oh. I think this is a bug in the block layer, we should not treat
a sync as write for the purposes of is read-only checks, as it never
writes data to the device. At the request layer we alread use
the proper REQ_OP_FLUSH, but at the bio layer we are still abusing
empty writes apparently. I'll try to cook up something over the
weekend.
next prev parent reply other threads:[~2019-11-22 19:14 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-24 21:15 [PATCH] block: Replace bio_check_ro()'s WARN_ON() Kees Cook
2019-11-22 18:53 ` Kees Cook
2019-11-22 18:55 ` Jens Axboe
2019-11-22 18:57 ` Kees Cook
2019-11-22 19:07 ` Christoph Hellwig
2019-11-22 19:09 ` Jens Axboe
2019-11-22 19:14 ` Christoph Hellwig [this message]
2019-11-22 19:34 ` Kees Cook
2019-11-25 17:40 ` Christoph Hellwig
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=20191122191434.GA10150@infradead.org \
--to=hch@infradead.org \
--cc=axboe@kernel.dk \
--cc=keescook@chromium.org \
--cc=linux-block@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=syzbot+21cfe1f803e0e158acf1@syzkaller.appspotmail.com \
/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).