[PATCH v2] virtio_ring: Check null pointer

[Jiasheng Jiang]

As the alloc_indirect_packed() returns kmalloc_array() that could
allocation fail and return null pointer, it should be check in order to
prevent the dereference of null pointer.

Fixes: 1ce9e6055fa0 ("virtio_ring: introduce packed ring support")
Signed-off-by: Jiasheng Jiang <jiasheng@xxxxxxxxxxx>
---
v2: Remove the redundant empty line.
---
 drivers/virtio/virtio_ring.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71e16b53e9c1..2923d8a68dc3 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -992,6 +992,10 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 
 	head = vq->packed.next_avail_idx;
 	desc = alloc_indirect_packed(total_sg, gfp);
+	if (!desc) {
+		END_USE(vq);
+		return -ENOMEM;
+	}
 
 	if (unlikely(vq->vq.num_free < 1)) {
 		pr_debug("Can't add buf len 1 - avail = 0\n");
-- 
2.25.1