Re: KASAN: use-after-free Read in locks_delete_block

From: Jeff Layton <jlayton@kernel.org>
To: Dmitry Vyukov <dvyukov@google.com>, Bruce Fields <bfields@fieldses.org>
Cc: NeilBrown <neilb@suse.com>,
	syzbot <syzbot+a4a3d526b4157113ec6a@syzkaller.appspotmail.com>,
	linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	syzkaller-bugs@googlegroups.com,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: KASAN: use-after-free Read in locks_delete_block
Date: Tue, 20 Nov 2018 06:08:34 -0500	[thread overview]
Message-ID: <abb5d9ab502e37ff9fdbbd50ec770fda72e12117.camel@kernel.org> (raw)
In-Reply-To: <CACT4Y+ag3mJNGUkjHQSyikT9xMJSjuY3fhSJ-2QH0eL1bTPhYw@mail.gmail.com>

On Tue, 2018-11-20 at 07:57 +0100, Dmitry Vyukov wrote:
> On Sat, Nov 17, 2018 at 3:03 PM, Bruce Fields <bfields@fieldses.org> wrote:
> > On Sat, Nov 17, 2018 at 08:33:27AM -0500, Jeff Layton wrote:
> > > Thanks for the explanation, Dmitry. I've added the tag to the patch in
> > > my tree. It should show up in linux-next soon.
> > > 
> > > I still find it a little misleading to say that syzbot reported a bug
> > > when it actually found a bug inside an earlier version of the patch, but
> > > I'll just learn to get over it.
> > 
> > The usual tag for someone that found a bug in an earlier version of a
> > patch would be Reviewed-by:.  Is there any reason we can't use that
> > here?  The "syzbot+..." email should be enough on its own, I can't see a
> > reason why their scripts would need to require a particular tag.  Or
> > maybe we could use Tested-by:, or some other tag made up for this case?
> > 
> > I do worry that someone who sees "Reported-by:..." might for example
> > mistakenly assume that it would help to backport that patch if they see
> > a similar-looking oops.
> 
> I see. It may also be picked by scripts that detects patches that need
> to be backported to stable because of the "Reported-by: syzbot" tag.
> This is somewhat unfortunate.
> 
> There is no problem parsing another tag on syzbot side. Does Tested-by
> look good to you? If it found a bug in the patch and then it was
> fixed, Tested-by looks reasonable. And we also detect
> Reported-and-tested-by already because that's what syzbot suggests
> after it tested a proposed fix for a bug.
> 
> I am somewhat concerned how to spread this information across all
> kernel developers. There is effectively no way to do this. We can't
> expect people to read docs, they generally don't. I guess I just
> document this at "See https://goo.gl/tpsmEJ for more information" and
> then we can point other people there if/when this concern pops up
> again.

Tested-by sounds like it might be a reasonable fit. I'll change the
patch in my tree to read that way.

Thanks,
-- 
Jeff Layton <jlayton@kernel.org>