virtio-gpu: avoid possible NULL pointer dereference

If output is NULL it is not permissable to dereference it.
So we should leave the respective function in this case.

The inconsistency was indicated by cppcheck.
No actual NULL pointer dereference was observed.

Signed-off-by: Heinrich Schuchardt <xypron.glpk@gmx.de>
Message-id: 1471813566-5324-1-git-send-email-xypron.glpk@gmx.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>

diff --git a/drivers/gpu/drm/virtio/virtgpu_plane.c b/drivers/gpu/drm/virtio/virtgpu_plane.c
index 925ca25209dfa12a60128b333d21d19fad9c03af..ba28c0f6f28a352b3f6f030b09be90d76eca6cec 100644 (file)
--- a/drivers/gpu/drm/virtio/virtgpu_plane.c
+++ b/drivers/gpu/drm/virtio/virtgpu_plane.c
@@ -76,7 +76,8 @@ static void virtio_gpu_primary_plane_update(struct drm_plane *plane,
                output = drm_crtc_to_virtio_gpu_output(plane->state->crtc);
        if (old_state->crtc)
                output = drm_crtc_to_virtio_gpu_output(old_state->crtc);
-       WARN_ON(!output);
+       if (WARN_ON(!output))
+               return;
 
        if (plane->state->fb) {
                vgfb = to_virtio_gpu_framebuffer(plane->state->fb);
@@ -129,7 +130,8 @@ static void virtio_gpu_cursor_plane_update(struct drm_plane *plane,
                output = drm_crtc_to_virtio_gpu_output(plane->state->crtc);
        if (old_state->crtc)
                output = drm_crtc_to_virtio_gpu_output(old_state->crtc);
-       WARN_ON(!output);
+       if (WARN_ON(!output))
+               return;
 
        if (plane->state->fb) {
                vgfb = to_virtio_gpu_framebuffer(plane->state->fb);