From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Omar Sandoval <osandov@fb.com>,
syzbot <syzbot+b382ba6a802a3d242790@syzkaller.appspotmail.com>,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
syzkaller-bugs@googlegroups.com, viro@zeniv.linux.org.uk,
Jens Axboe <axboe@fb.com>
Subject: Re: BUG: unable to handle kernel paging request in dput (2)
Date: Wed, 30 Jan 2019 12:34:10 +0100 [thread overview]
Message-ID: <20190130113410.GA30781@kroah.com> (raw)
In-Reply-To: <27008e5f-9dfc-a09a-cdb9-824d470fb9dd@I-love.SAKURA.ne.jp>
On Wed, Jan 30, 2019 at 08:26:24PM +0900, Tetsuo Handa wrote:
> On 2019/01/30 20:11, Tetsuo Handa wrote:
> > Hello, Omar.
> >
> > syzbot is reporting a crash due to dput(-EINVAL) [1]. I think the location is
> >
> > dir = debugfs_lookup(buts->name, blk_debugfs_root);
> > if (!dir)
> > bt->dir = dir = debugfs_create_dir(buts->name, blk_debugfs_root);
> >
> > added by commit 6ac93117ab009d39 ("blktrace: use existing disk debugfs directory").
> >
> > Currently, Greg Kroah-Hartman is posting patches:
> >
> > When calling debugfs functions, there is no need to ever check the
> > return value. The function can work or not, but the code logic should
> > never do something different based on this.
> >
> > Omar, what do you want to do for this case?
> >
> > [1] https://syzkaller.appspot.com/bug?extid=b382ba6a802a3d242790
> >
>
> The function which returned -EINVAL instead of NULL seems to be debugfs_lookup()
> modified by commit ff9fb72bc07705c0 ("debugfs: return error values, not NULL").
Ah, my fault then, yes, debugfs_lookup() should return NULL if nothing
is found. My patch was wrong, let me go fix this up, thanks for the
report.
greg k-h
next prev parent reply other threads:[~2019-01-30 11:34 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-01-30 10:35 BUG: unable to handle kernel paging request in dput (2) syzbot
2019-01-30 11:11 ` Tetsuo Handa
2019-01-30 11:23 ` Greg Kroah-Hartman
2019-01-30 11:26 ` Tetsuo Handa
2019-01-30 11:34 ` Greg Kroah-Hartman [this message]
2019-01-30 11:40 ` Greg Kroah-Hartman
2019-01-31 10:09 ` Kees Cook
2019-01-31 10:18 ` Tetsuo Handa
2019-01-31 10:53 ` Greg Kroah-Hartman
2019-01-30 11:20 ` syzbot
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