From: Al Viro <viro@zeniv.linux.org.uk>
To: Jan Kara <jack@suse.cz>
Cc: 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 14:18:21 +0100 [thread overview]
Message-ID: <20190430131820.GK23075@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20190430130739.GA11224@quack2.suse.cz>
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.
next prev parent reply other threads:[~2019-04-30 13:18 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 [this message]
2019-04-30 15:07 ` Jan Kara
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
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