On Thu, May 5, 2022 at 6:08 PM Xie Yongji <xieyongji@xxxxxxxxxxxxx> wrote: > > 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@xxxxxxxxxxxxx> > Signed-off-by: Fam Zheng <fam.zheng@xxxxxxxxxxxxx> > --- > 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 14e2043d7685..eab55accf381 100644 > --- a/drivers/vhost/vringh.c > +++ b/drivers/vhost/vringh.c > @@ -292,7 +292,7 @@ __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; > @@ -349,7 +349,12 @@ __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; > @@ -411,6 +416,7 @@ __vringh_iov(struct vringh *vrh, u16 i, > i = return_from_indirect(vrh, &up_next, > &descs, &desc_max); > slow = false; > + indirect_count = 0; Do we need to reset up_next to -1 here? Thanks > } else > break; > } > -- > 2.20.1 >