From:   Jiasheng Jiang <jiasheng@iscas.ac.cn>
To:     mst@redhat.com, jasowang@redhat.com
Cc:     virtualization@lists.linux-foundation.org,
        linux-kernel@vger.kernel.org, Jiasheng Jiang <jiasheng@iscas.ac.cn>
Subject: [PATCH] virtio_ring: Check null pointer
Date:   Fri, 24 Dec 2021 18:10:07 +0800
Message-Id: <20211224101007.1635703-1-jiasheng@iscas.ac.cn>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

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@iscas.ac.cn>
---
 drivers/virtio/virtio_ring.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 71e16b53e9c1..30fd925165ac 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -991,7 +991,12 @@ static int virtqueue_add_indirect_packed(struct vring_virtqueue *vq,
 	dma_addr_t addr;
 
 	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