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From:   Daniel Vetter <daniel@ffwll.ch>
Date:   Mon, 6 Apr 2020 14:41:20 +0200
Message-ID: <CAKMK7uE9uQ_YCXfDOH9zQBu_ffoz546hqRd1R_r1+L-T072Lew@mail.gmail.com>
Subject: Re: upstream boot error: KASAN: slab-out-of-bounds Write in virtio_gpu_object_create
To:     Gerd Hoffmann <kraxel@redhat.com>
Cc:     Dmitry Vyukov <dvyukov@google.com>,
        syzbot <syzbot+d3a7951ed361037407db@syzkaller.appspotmail.com>,
        David Airlie <airlied@linux.ie>,
        DRI <dri-devel@lists.freedesktop.org>,
        "open list:VIRTIO CORE, NET..." 
        <virtualization@lists.linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Mon, Apr 6, 2020 at 10:06 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
> On Mon, Apr 06, 2020 at 09:07:44AM +0200, Dmitry Vyukov wrote:
> > On Mon, Apr 6, 2020 at 8:46 AM syzbot
> > <syzbot+d3a7951ed361037407db@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot found the following crash on:
> > >
> > > HEAD commit:    ffc1c20c Merge tag 'for-5.7/dm-changes' of git://git.kerne..
> > > git tree:       upstream
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=1690471fe00000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=d6a1e2f9a9986236
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=d3a7951ed361037407db
> > > compiler:       gcc (GCC) 9.0.0 20181231 (experimental)
> > >
> > > Unfortunately, I don't have any reproducer for this crash yet.
> > >
> > > IMPORTANT: if you fix the bug, please add the following tag to the commit:
> > > Reported-by: syzbot+d3a7951ed361037407db@syzkaller.appspotmail.com
> >
> >
> > +drivers/gpu/drm/virtio/virtgpu_object.c maintainers
> > Now we have both mainline and linux-next boot broken (linux-next is
> > broken for the past 40 days).
> > No testing of new code happens.
> >
> > >  virtio_gpu_object_shmem_init drivers/gpu/drm/virtio/virtgpu_object.c:151 [inline]
> > >  virtio_gpu_object_create+0x9f3/0xaa0 drivers/gpu/drm/virtio/virtgpu_object.c:230
>
> Ah, that one.
>
> broken patch: f651c8b05542 ("drm/virtio: factor out the sg_table from virtio_gpu_object")
> fixed by: 0666a8d7f6a4 ("drm/virtio: fix OOB in virtio_gpu_object_create")
>
> Both are in drm-misc-next.  I suspect the fix was added after
> drm-misc-next was closed for the 5.7 merge window and thus should
> have been submitted to drm-misc-next-fixes instead.
>
> So, what to do now?  Should I cherry-pick 0666a8d7f6a4 into
> drm-misc-next-fixes?  Or should it go into drm-misc-fixes instead?

Yup cherry-pick it over, with -x, to drm-misc-next-fixes.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch