drm/nouveau/fbcon: fix NULL pointer access in nouveau_fbcon_destroy

When the fbcon object is initialized, but nouveau_fbcon_create is not
called, we run into a NULL pointer access within nouveau_fbcon_create when
unloading nouveau.

The call to drm_fb_helper_funcs.fb_probe is deferred until there is a
display for real since 4.14, that's why fbcon->helper.fb is still not set.

Signed-off-by: Karol Herbst <kherbst@redhat.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nouveau_fbcon.c b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
index c533d8e04afc0f1fc4708d85e069323291c428c3..be7357bf2246e6ae326c9b6750c2c183cb0974d9 100644 (file)
--- a/drivers/gpu/drm/nouveau/nouveau_fbcon.c
+++ b/drivers/gpu/drm/nouveau/nouveau_fbcon.c
@@ -429,7 +429,7 @@ nouveau_fbcon_destroy(struct drm_device *dev, struct nouveau_fbdev *fbcon)
        drm_fb_helper_unregister_fbi(&fbcon->helper);
        drm_fb_helper_fini(&fbcon->helper);
 
-       if (nouveau_fb->nvbo) {
+       if (nouveau_fb && nouveau_fb->nvbo) {
                nouveau_vma_del(&nouveau_fb->vma);
                nouveau_bo_unmap(nouveau_fb->nvbo);
                nouveau_bo_unpin(nouveau_fb->nvbo);