linux-fsdevel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "J. Bruce Fields" <bfields@fieldses.org>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	syzbot <syzbot+1f371ca19b341a276761@syzkaller.appspotmail.com>,
	jlayton@kernel.org, linux-fsdevel <linux-fsdevel@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	syzkaller-bugs <syzkaller-bugs@googlegroups.com>,
	Al Viro <viro@zeniv.linux.org.uk>
Subject: Re: general protection fault in send_sigurg_to_task
Date: Fri, 17 Aug 2018 14:38:40 -0400	[thread overview]
Message-ID: <20180817183840.GA12582@fieldses.org> (raw)
In-Reply-To: <87d0ugc0pk.fsf@xmission.com>

On Fri, Aug 17, 2018 at 01:22:31PM -0500, Eric W. Biederman wrote:
> Dmitry Vyukov <dvyukov@google.com> writes:
> 
> > On Wed, Aug 15, 2018 at 9:01 PM, Eric W. Biederman
> > <ebiederm@xmission.com> wrote:
> >> Dmitry Vyukov <dvyukov@google.com> writes:
> >>
> >>> On Tue, Aug 14, 2018 at 12:11 PM, J. Bruce Fields <bfields@fieldses.org> wrote:
> >>>> On Mon, Aug 13, 2018 at 06:33:02AM -0700, syzbot wrote:
> >>>>> syzbot has found a reproducer for the following crash on:
> >>>>>
> >>>>> HEAD commit:    5ed5da74de9e Add linux-next specific files for 20180813
> >>>>> git tree:       linux-next
> >>>>
> >>>> I fetched linux-next but don't have 5ed5da74de9e.
> >>>
> >>> Hi Bruce,
> >>>
> >>> +Stephen for the disappeared linux-next commit.
> >>>
> >>> On the dashboard link you can see that it also happened on a more
> >>> recent commit 4e8b38549b50459a22573d756dd1f4e1963c2a8d that I do see
> >>> now in linux-next.
> >>>
> >>>> I'm also not sure why I'm on the cc for this.
> >>>
> >>> You've been pointed to by "./scripts/get_maintainer.pl -f fs/fcntl.c"
> >>> as maintainer of the file, which is the file where the crash happened.
> >>
> >> You need to use your reproducer to bisect and find the commit that
> >> caused this.  Otherwise you will continue to confuse people.
> >>
> >> get_maintainer.pl is not a good target for automated reporting
> >> especially against linux-next.
> >
> > Hi Eric,
> >
> > We will do bisection.
> > But I afraid it will not give perfect attribution for a number of reasons:
> >  - broken build/boot which happens sometimes for prolonged periods and
> > prohibits bisection
> >  - elusive races that can't be reproduced reliably and thus bisection
> > can give wrong results
> >  - bugs introduced too long ago (e.g. author email is not even valid today)
> >  - reproducers triggering more than 1 bug, so base bisection commit
> > can actually be for another bug, or bisection can switch from one bug
> > to another
> >  - last but not least, bugs without reproducers
> > Bisection will add useful information to the bug report, but it will
> > not necessary make attribution better than it is now.
> >
> > Do you have more examples where bugs were misreported? From what I see
> > current attrition works well. There are episodic fallouts, but well,
> > nothing is perfect in this world. Humans don't bisect frequently and
> > misreport sometimes. I think we just need to re-route bugs in such
> > cases.
> 
> I have yet to see syzbot make a good report.  Especially against
> linux-next.

It did result in a fix (thanks!): https://lkml.org/lkml/2018/8/16/47

So I'd call that a better-than-nothing report if not a great report?

There's some value just in timeliness; it's a lot easier for me to fix a
bug that I introduced in the last few days, with the change still fresh
in my mind....

--b.

  reply	other threads:[~2018-08-17 21:43 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-13 12:54 general protection fault in send_sigurg_to_task syzbot
2018-08-13 13:33 ` syzbot
2018-08-14 19:11   ` J. Bruce Fields
2018-08-14 20:50     ` Dmitry Vyukov
2018-08-15  0:11       ` Stephen Rothwell
2018-08-15 18:53         ` J. Bruce Fields
2018-08-15 20:35       ` J. Bruce Fields
2018-08-16  4:01       ` Eric W. Biederman
2018-08-17 17:26         ` Dmitry Vyukov
2018-08-17 18:22           ` Eric W. Biederman
2018-08-17 18:38             ` J. Bruce Fields [this message]
2018-08-17 18:42             ` Dmitry Vyukov

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=20180817183840.GA12582@fieldses.org \
    --to=bfields@fieldses.org \
    --cc=dvyukov@google.com \
    --cc=ebiederm@xmission.com \
    --cc=jlayton@kernel.org \
    --cc=linux-fsdevel@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=sfr@canb.auug.org.au \
    --cc=syzbot+1f371ca19b341a276761@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).