Re: KMSAN: uninit-value in snd_midi_event_encode_byte

[Takashi Iwai <tiwai@suse.de>]

On Mon, 03 Sep 2018 19:25:39 +0200,
Dmitry Vyukov wrote:
> 
> On Mon, Sep 3, 2018 at 5:18 PM, Takashi Iwai <tiwai@suse.de> wrote:
> > On Mon, 03 Sep 2018 17:06:05 +0200,
> > Dmitry Vyukov wrote:
> >>
> >> On Mon, Sep 3, 2018 at 5:00 PM, Takashi Iwai <tiwai@suse.de> wrote:
> >> > On Mon, 03 Sep 2018 16:54:23 +0200,
> >> > Dmitry Vyukov wrote:
> >> >>
> >> >> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#kmsan-bugs
> >> >> is meant to be a complement to the previous generic descriptions of
> >> >> patch testing process, which is:
> >> >> https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
> >> >>
> >> >> So, you always reply to the syzbot+HASH email address so that syzbot
> >> >> understands which bug we are talking about.
> >> >> Then you do either (omitting # so that syzbot won't consider that as
> >> >> actual test requests):
> >> >>
> >> >> syz test: git://repo/address.git branch
> >> >>
> >> >> or:
> >> >>
> >> >> syz test: git://repo/address.git commit-hash
> >> >>
> >> >> And then you can either attach a patch that needs to be applied on
> >> >> top, or not attach it (if it's already in the tree, or you just want
> >> >> to get another crash report).
> >> >
> >> > OK, so far, so good, it's what I knew and have done a few times.
> >> >
> >> >
> >> >> For KMSAN you need to issue test request against
> >> >> "https//github.com/google/kmsan.git master" (that's the only tree that
> >> >> has KMSAN tool in it) and you need to attach/inline the patch (because
> >> >> your patch is obviously not there yet).
> >> >>
> >> >> Does this make things more clear?
> >> >
> >> > Sorry, the part "issue test request against https..." still isn't
> >> > clear.
> >> >
> >> > Do you mean to open an issue entry on github, and attach the patch
> >> > there?
> >>
> >> By "issue test request" I mean sending email with "syz test" command.
> >> So overall you send "syz test https//github.com/google/kmsan.git
> >> master" and attach the patch.
> >> The workflow is all the same, and no github involved. It's just that
> >> you can't ask to test it against
> >> git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound.git because
> >> it does not have KMSAN tool and so no KMSAN bugs will be detected
> >> there.
> >
> > Thanks, this finally made me understanding the whole picture!
> >
> >> Since I did all of this, it's hard for me to write clear docs for others. Sorry.
> >> If you can suggest some improved wording, it would be great.
> >
> > Well, how about like below?
> >
> >
> > KMSAN is not upstream yet, though, we want to upstream it later. For
> > now, it lives in github.com/google/kmsan and is based on a reasonably
> > fresh upstream tree. As the result, any patch testing requests for
> > KMSAN bugs need to go to KMSAN tree
> > (https://github.com/google/kmsan.git repo, master branch).
> > A standard way for triggering the test with KMSAN tree is to send an
> > email to syzbot+HASH address containing the following line:
> >
> >   #syz test: https://github.com/google/kmsan.git master
> >
> > and attach/inline your test patch in the same mail.
> 
> 
> Done:
> https://github.com/google/syzkaller/commit/3ea6c028b154d2faea45142bfb15b02f3243800c#diff-5b3b5ff5f03b01e1d31ec93aafd2f3d5

Thanks!

And about the bug in the subject: as syzbot returned a positive
feedback for my test patch, I queued it to for-linus branch now.


Takashi