From: Jan Kara <jack@suse.cz>
To: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jan Kara <jack@suse.cz>,
syzbot <syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com>,
axboe@kernel.dk, dvyukov@google.com,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
penguin-kernel@i-love.sakura.ne.jp,
syzkaller-bugs@googlegroups.com
Subject: Re: INFO: task hung in __get_super
Date: Tue, 30 Apr 2019 17:07:53 +0200 [thread overview]
Message-ID: <20190430150753.GA14000@quack2.suse.cz> (raw)
In-Reply-To: <20190430131820.GK23075@ZenIV.linux.org.uk>
On Tue 30-04-19 14:18:21, Al Viro wrote:
> On Tue, Apr 30, 2019 at 03:07:39PM +0200, Jan Kara wrote:
> > On Tue 30-04-19 04:11:44, Al Viro wrote:
> > > On Tue, Apr 30, 2019 at 04:55:01AM +0200, Jan Kara wrote:
> > >
> > > > Yeah, you're right. And if we push the patch a bit further to not take
> > > > loop_ctl_mutex for invalid ioctl number, that would fix the problem. I
> > > > can send a fix.
> > >
> > > Huh? We don't take it until in lo_simple_ioctl(), and that patch doesn't
> > > get to its call on invalid ioctl numbers. What am I missing here?
> >
> > Doesn't it? blkdev_ioctl() calls into __blkdev_driver_ioctl() for
> > unrecognized ioctl numbers. That calls into lo_ioctl() in case of a loop
> > device. lo_ioctl() calls into lo_simple_ioctl() for ioctl numbers it
> > doesn't recognize and lo_simple_ioctl() will lock loop_ctl_mutex as you
> > say.
>
> Not with the patch upthread. lo_ioctl() part was
>
> @@ -1567,10 +1564,9 @@ static int lo_ioctl(struct block_device *bdev, fmode_t mode,
> case LOOP_SET_BLOCK_SIZE:
> if (!(mode & FMODE_WRITE) && !capable(CAP_SYS_ADMIN))
> return -EPERM;
> - /* Fall through */
> + return lo_simple_ioctl(lo, cmd, arg);
> default:
> - err = lo_simple_ioctl(lo, cmd, arg);
> - break;
> + return -EINVAL;
> }
>
> return err;
>
> so anything unrecognized doesn't make it to lo_simple_ioctl() at all.
Ah, right. I've missed that in your patch. So your patch should be really
fixing the problem. Will you post it officially? Thanks!
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-04-30 15:08 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-01 17:08 INFO: task hung in __get_super syzbot
2018-06-19 11:44 ` Tetsuo Handa
2018-06-19 11:53 ` Dmitry Vyukov
2018-06-19 14:10 ` Tetsuo Handa
2018-06-19 14:15 ` Dmitry Vyukov
2018-06-20 1:15 ` Tetsuo Handa
2019-04-28 18:14 ` syzbot
2019-04-28 18:51 ` Al Viro
2019-04-29 1:38 ` Tetsuo Handa
2019-04-29 5:30 ` Dmitry Vyukov
2019-04-30 2:55 ` Jan Kara
2019-04-30 3:11 ` Al Viro
2019-04-30 13:07 ` Jan Kara
2019-04-30 13:18 ` Al Viro
2019-04-30 15:07 ` Jan Kara [this message]
2019-04-30 15:34 ` Tetsuo Handa
2019-05-03 10:29 ` Tetsuo Handa
2019-05-14 5:15 ` Tetsuo Handa
2019-05-15 1:02 ` Tetsuo Handa
2019-05-15 10:21 ` Jan Kara
2019-05-15 11:32 ` Tetsuo Handa
2019-05-15 13:07 ` Jan Kara
2019-05-16 11:48 ` Jan Kara
2019-05-16 12:17 ` Tetsuo Handa
2019-05-16 12:32 ` Jan Kara
2019-05-16 12:50 ` Tetsuo Handa
2019-05-16 12:33 ` syzbot
2019-05-15 11:59 ` syzbot
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=20190430150753.GA14000@quack2.suse.cz \
--to=jack@suse.cz \
--cc=axboe@kernel.dk \
--cc=dvyukov@google.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=syzbot+10007d66ca02b08f0e60@syzkaller.appspotmail.com \
--cc=syzkaller-bugs@googlegroups.com \
--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).