[PATCH 5.17 30/39] drm/virtio: Ensure that objs is not NULL in virtio_gpu_array_put_free()

[Greg Kroah-Hartman]

From: Roberto Sassu <roberto.sassu@xxxxxxxxxx>

commit 6b79f96f4a23846516e5e6e4dd37fc06f43a60dd upstream.

If virtio_gpu_object_shmem_init() fails (e.g. due to fault injection, as it
happened in the bug report by syzbot), virtio_gpu_array_put_free() could be
called with objs equal to NULL.

Ensure that objs is not NULL in virtio_gpu_array_put_free(), or otherwise
return from the function.

Cc: stable@xxxxxxxxxxxxxxx # 5.13.x
Signed-off-by: Roberto Sassu <roberto.sassu@xxxxxxxxxx>
Reported-by: syzbot+e9072e90624a31dfa85f@xxxxxxxxxxxxxxxxxxxxxxxxx
Fixes: 377f8331d0565 ("drm/virtio: fix possible leak/unlock virtio_gpu_object_array")
Link: http://patchwork.freedesktop.org/patch/msgid/20211213183122.838119-1-roberto.sassu@xxxxxxxxxx
Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
 drivers/gpu/drm/virtio/virtgpu_gem.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/gpu/drm/virtio/virtgpu_gem.c
+++ b/drivers/gpu/drm/virtio/virtgpu_gem.c
@@ -248,6 +248,9 @@ void virtio_gpu_array_put_free(struct vi
 {
 	u32 i;
 
+	if (!objs)
+		return;
+
 	for (i = 0; i < objs->nents; i++)
 		drm_gem_object_put(objs->objs[i]);
 	virtio_gpu_array_free(objs);