Re: [PATCH] virtio-gpu/virgl: free BHs and timers on renderer reset

["Alex Bennée" <alex.bennee@linaro.org>]

Marc-André Lureau <marcandre.lureau@redhat.com> writes:

> Hi
>
> On Thu, Aug 27, 2026 at 8:11 PM Alex Bennée <alex.bennee@linaro.org> wrote:
>>
>> marcandre.lureau@redhat.com writes:
>>
>> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
>> >
>> > virtio_gpu_virgl_reset() does not free the bottom halves or timers
>> > allocated by the previous virtio_gpu_virgl_init() call. A subsequent
>> > virtio_gpu_virgl_init() overwrites the old pointers, leaking the
>> > previous allocations.
>> >
>> > Fixes: bd9258917fbf ("virtio-gpu: Destroy virgl resources on virtio-gpu reset")
>> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>> > ---
>> >  hw/display/virtio-gpu-virgl.c | 6 ++++++
>> >  1 file changed, 6 insertions(+)
>> >
>> > diff --git a/hw/display/virtio-gpu-virgl.c b/hw/display/virtio-gpu-virgl.c
>> > index 0b79aef8d1f5..8bf6417c6514 100644
>> > --- a/hw/display/virtio-gpu-virgl.c
>> > +++ b/hw/display/virtio-gpu-virgl.c
>> > @@ -1425,6 +1425,7 @@ void virtio_gpu_virgl_reset_scanout(VirtIOGPU *g)
>> >
>> >  static bool virtio_gpu_virgl_reset(VirtIOGPU *g)
>> >  {
>> > +    VirtIOGPUGL *gl = VIRTIO_GPU_GL(g);
>> >      struct virtio_gpu_simple_resource *res, *tmp;
>> >
>> >      /*
>> > @@ -1443,6 +1444,11 @@ static bool virtio_gpu_virgl_reset(VirtIOGPU *g)
>> >
>> >      virtio_gpu_virgl_reset_async_fences(g);
>> >
>> > +    g_clear_pointer(&gl->cmdq_resume_bh, qemu_bh_delete);
>> > +    g_clear_pointer(&gl->async_fence_bh, qemu_bh_delete);
>> > +    g_clear_pointer(&gl->print_stats, timer_free);
>> > +    g_clear_pointer(&gl->fence_poll, timer_free);
>> > +
>>
>> Don't we need some ptr checks in virtio_gpu_gl_device_unrealize so a
>> reset followed by an unplug doesn't causes segs chasing now NULL
>> pointers?
>
> Good point, actually we should be safe, since render_state < RS_INITED.
>
> But those qemu_bh_delete().. can we make it safe to call with NULL?

That seems sane as it will be on the exit path. I wouldn't tolerate
NULL for any of the other qemu_bh functions though.

> timer_free() was fixed already.
>
>>
>>
>> >      return true;
>> >  }
>>
>> --
>> Alex Bennée
>> Virtualisation Tech Lead @ Linaro
>>

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro