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Commit 4511b505 authored by Xie Yongji's avatar Xie Yongji Committed by Greg Kroah-Hartman
Browse files

vringh: Fix loop descriptors check in the indirect cases 



[ 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: f87d0fbb ("vringh: host-side implementation of virtio rings.")
Signed-off-by: default avatarXie Yongji <xieyongji@bytedance.com>
Signed-off-by: default avatarFam Zheng <fam.zheng@bytedance.com>
Message-Id: <20220505100910.137-1-xieyongji@bytedance.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
parent 727d7f62

drivers/vhost/vringh.c

+8 −2
Original line number Diff line number Diff line
@@ -263,7 +263,7 @@ __vringh_iov(struct vringh *vrh, u16 i, 
	     gfp_t gfp,

	     int (*copy)(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;
@@ -320,7 +320,12 @@ __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;
@@ -382,6 +387,7 @@ __vringh_iov(struct vringh *vrh, u16 i, 
				i = return_from_indirect(vrh, &up_next,

							 &descs, &desc_max);

				slow = false;

				indirect_count = 0;

			} else

				break;

		}