From: Xie Yongji xieyongji@bytedance.com
stable inclusion from stable-v5.10.122 commit b6ea26873edbd9ca3c0c338c9de856de7f1fcede category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I5W6OE
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...
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[ Upstream commit dbd29e0752286af74243cf891accf472b2f3edd8 ]
We should use size of descriptor chain to test loop condition in the indirect case. And another statistical count is also introduced for indirect descriptors to avoid conflict with the statistical count of direct descriptors.
Fixes: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") Signed-off-by: Xie Yongji xieyongji@bytedance.com Signed-off-by: Fam Zheng fam.zheng@bytedance.com Message-Id: 20220505100910.137-1-xieyongji@bytedance.com Signed-off-by: Michael S. Tsirkin mst@redhat.com Acked-by: Jason Wang jasowang@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com Reviewed-by: Wei Li liwei391@huawei.com --- drivers/vhost/vringh.c | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 0bd7e64331f0..5a0340c85dc6 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -274,7 +274,7 @@ __vringh_iov(struct vringh *vrh, u16 i, int (*copy)(const struct vringh *vrh, void *dst, const void *src, size_t len)) { - int err, count = 0, up_next, desc_max; + int err, count = 0, indirect_count = 0, up_next, desc_max; struct vring_desc desc, *descs; struct vringh_range range = { -1ULL, 0 }, slowrange; bool slow = false; @@ -331,7 +331,12 @@ __vringh_iov(struct vringh *vrh, u16 i, continue; }
- if (count++ == vrh->vring.num) { + if (up_next == -1) + count++; + else + indirect_count++; + + if (count > vrh->vring.num || indirect_count > desc_max) { vringh_bad("Descriptor loop in %p", descs); err = -ELOOP; goto fail; @@ -393,6 +398,7 @@ __vringh_iov(struct vringh *vrh, u16 i, i = return_from_indirect(vrh, &up_next, &descs, &desc_max); slow = false; + indirect_count = 0; } else break; }