This is a note to let you know that I've just added the patch titled virtio_ring: check desc == NULL when using indirect with packed to the 5.15-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: virtio_ring-check-desc-null-when-using-indirect-with.patch and it can be found in the queue-5.15 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit dac021549bb8791a3a64011c78db9ae13a599730 Author: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> Date: Wed Oct 20 19:23:23 2021 +0800 virtio_ring: check desc == NULL when using indirect with packed [ Upstream commit fc6d70f40b3d0b3219e2026d05be0409695f620d ] When using indirect with packed, we don't check for allocation failures. This patch checks that and fall back on direct. Fixes: 1ce9e6055fa0 ("virtio_ring: introduce packed ring support") Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx> Link: https://lore.kernel.org/r/20211020112323.67466-3-xuanzhuo@xxxxxxxxxxxxxxxxx Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 3035bb6f54585..d1f47327f6cfe 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -1065,6 +1065,8 @@ 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) + return -ENOMEM; if (unlikely(vq->vq.num_free < 1)) { pr_debug("Can't add buf len 1 - avail = 0\n"); @@ -1176,6 +1178,7 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, unsigned int i, n, c, descs_used, err_idx; __le16 head_flags, flags; u16 head, id, prev, curr, avail_used_flags; + int err; START_USE(vq); @@ -1191,9 +1194,14 @@ static inline int virtqueue_add_packed(struct virtqueue *_vq, BUG_ON(total_sg == 0); - if (virtqueue_use_indirect(_vq, total_sg)) - return virtqueue_add_indirect_packed(vq, sgs, total_sg, - out_sgs, in_sgs, data, gfp); + if (virtqueue_use_indirect(_vq, total_sg)) { + err = virtqueue_add_indirect_packed(vq, sgs, total_sg, out_sgs, + in_sgs, data, gfp); + if (err != -ENOMEM) + return err; + + /* fall back on direct */ + } head = vq->packed.next_avail_idx; avail_used_flags = vq->packed.avail_used_flags;