Re: WARNING in kernfs_get

[Dmitry Vyukov]

On Wed, Nov 20, 2019 at 9:30 AM Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, Nov 20, 2019 at 12:17:01AM -0800, syzbot wrote:
> > syzbot has bisected this bug to:
> >
> > commit 726e41097920a73e4c7c33385dcc0debb1281e18
> > Author: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
> > Date:   Tue Jul 10 00:29:10 2018 +0000
> >
> >     drivers: core: Remove glue dirs from sysfs earlier
> >
> > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=17a101cee00000
> > start commit:   9a568276 Merge branch 'x86-urgent-for-linus' of git://git...
> > git tree:       upstream
> > final crash:    https://syzkaller.appspot.com/x/report.txt?x=146101cee00000
> > console output: https://syzkaller.appspot.com/x/log.txt?x=106101cee00000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=8f59875069d721b6
> > dashboard link: https://syzkaller.appspot.com/bug?extid=3dcb532381f98c86aeb1
> > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=12657f0a400000
> > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=117728ae400000
> >
> > Reported-by: syzbot+3dcb532381f98c86aeb1@xxxxxxxxxxxxxxxxxxxxxxxxx
> > Fixes: 726e41097920 ("drivers: core: Remove glue dirs from sysfs earlier")
> >
> > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
>
> Again, I think this should be resolved with ac43432cb1f5 ("driver core:
> Fix use-after-free and double free on glue directory")
>
> Is there any way to run the reproducer on a newer tree?

The generic fix testing instruction should work:
https://github.com/google/syzkaller/blob/master/docs/syzbot.md#testing-patches
Note: you don't need to attach any patch, just pointing to a
tree/branch works too.