From: Xie Yongji Date: Thu, 5 May 2022 10:09:10 +0000 (+0800) Subject: vringh: Fix loop descriptors check in the indirect cases X-Git-Tag: v5.4.198~15 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1a36f77dc23c3768e06cdc32777b2d85be7f4150;p=thirdparty%2Fkernel%2Fstable.git 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: f87d0fbb5798 ("vringh: host-side implementation of virtio rings.") Signed-off-by: Xie Yongji Signed-off-by: Fam Zheng Message-Id: <20220505100910.137-1-xieyongji@bytedance.com> Signed-off-by: Michael S. Tsirkin Acked-by: Jason Wang Signed-off-by: Sasha Levin --- diff --git a/drivers/vhost/vringh.c b/drivers/vhost/vringh.c index 4653de001e261..264cbe385a63b 100644 --- a/drivers/vhost/vringh.c +++ b/drivers/vhost/vringh.c @@ -264,7 +264,7 @@ __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; @@ -321,7 +321,12 @@ __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; @@ -383,6 +388,7 @@ __vringh_iov(struct vringh *vrh, u16 i, i = return_from_indirect(vrh, &up_next, &descs, &desc_max); slow = false; + indirect_count = 0; } else break; }