drm/vmwgfx: Fix oops on failing bo pin

When bo pin failed during modesetting,
vmwgfx would try to unref a non-existing buffer object.

Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index 87c6e6156d7d..cceeb42789b6 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -720,6 +720,8 @@ static int vmw_surface_dmabuf_pin(struct vmw_framebuffer *vfb)
                                &vmw_vram_ne_placement,
                                false, &vmw_dmabuf_bo_free);
         vmw_overlay_resume_all(dev_priv);
+        if (unlikely(ret != 0))
+                vfbs->buffer = NULL;
 
         return ret;
 }
@@ -730,6 +732,9 @@ static int vmw_surface_dmabuf_unpin(struct vmw_framebuffer *vfb)
         struct vmw_framebuffer_surface *vfbs =
                 vmw_framebuffer_to_vfbs(&vfb->base);
 
+        if (unlikely(vfbs->buffer == NULL))
+                return 0;
+
         bo = &vfbs->buffer->base;
         ttm_bo_unref(&bo);
         vfbs->buffer = NULL;