From c8447cb14a125ba25255e4d6b380ce7a14a3fecd Mon Sep 17 00:00:00 2001 From: Xuan Zhuo Date: Wed, 20 Oct 2021 19:23:23 +0800 Subject: [PATCH] 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 Link: https://lore.kernel.org/r/20211020112323.67466-3-xuanzhuo@linux.alibaba.com Signed-off-by: Michael S. Tsirkin Signed-off-by: Sasha Levin --- drivers/virtio/virtio_ring.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 6c730d6d50f71..e9432dbbec0a7 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -992,6 +992,8 @@ 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"); @@ -1103,6 +1105,7 @@ 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); @@ -1118,9 +1121,14 @@ 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;