[PATCH] drm/vmwgfx: avoid null_ptr_deref in vmw_framebuffer_surface_create_handle

[Chen Ridong]

From: Chen Ridong <chenrid...@huawei.com>

The 'vmw_user_object_buffer' function may return NULL with incorrect
inputs. To avoid possible null pointer dereference, add a check whether
the 'bo' is NULL in the vmw_framebuffer_surface_create_handle.

Fixes: d6667f0ddf46 ("drm/vmwgfx: Fix handling of dumb buffers")
Signed-off-by: Chen Ridong <chenrid...@huawei.com>
---
 drivers/gpu/drm/vmwgfx/vmwgfx_kms.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c 
b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
index f39bf992364d..8db38927729b 100644
--- a/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_kms.c
@@ -1265,6 +1265,8 @@ static int vmw_framebuffer_surface_create_handle(struct 
drm_framebuffer *fb,
        struct vmw_framebuffer_surface *vfbs = vmw_framebuffer_to_vfbs(fb);
        struct vmw_bo *bo = vmw_user_object_buffer(&vfbs->uo);
 
+       if (WARN_ON(!bo))
+               return -EINVAL;
        return drm_gem_handle_create(file_priv, &bo->tbo.base, handle);
 }
 
-- 
2.34.1