Linux Virtualization - Apr 2020 - upstream boot error: KASAN: slab-out-of-bounds Write in virtio_gpu_object_create

On Mon, Apr 6, 2020 at 10:06 AM Gerd Hoffmann <kraxel at 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 at 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 at
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

Hi,
> > > +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
Done.  So the next linux-next build should be green again.  mainline
should get the fix with the next drm pull (may take a few days).

take care,
  Gerd

On Mon, Apr 6, 2020 at 3:16 PM Gerd Hoffmann <kraxel at redhat.com>
wrote:
>
>   Hi,
>
> > > > +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
>
> Done.  So the next linux-next build should be green again.
Linux-next is boot broken with 2 or 3 other bugs for a month. This
won't fix linux-next.