Messages in this thread | | | Date | Tue, 7 Jan 2014 15:23:15 +0000 | From | Zoltan Kiss <> | Subject | Re: [PATCH net-next v2 6/9] xen-netback: Handle guests with too many frags |
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On 16/12/13 18:09, Wei Liu wrote: >>>> diff --git a/drivers/net/xen-netback/netback.c b/drivers/net/xen-netback/netback.c >>>> index e26cdda..f6ed1c8 100644 >>>> --- a/drivers/net/xen-netback/netback.c >>>> +++ b/drivers/net/xen-netback/netback.c >>>> @@ -906,11 +906,15 @@ static struct gnttab_map_grant_ref *xenvif_get_requests(struct xenvif *vif, >>>> u16 pending_idx = *((u16 *)skb->data); >>>> int start; >>>> pending_ring_idx_t index; >>>> - unsigned int nr_slots; >>>> + unsigned int nr_slots, frag_overflow = 0; >>>> >>>> /* At this point shinfo->nr_frags is in fact the number of >>>> * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. >>>> */ >>>> + if (shinfo->nr_frags > MAX_SKB_FRAGS) { >>>> + frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS; >>>> + shinfo->nr_frags = MAX_SKB_FRAGS; >>>> + } >>>> nr_slots = shinfo->nr_frags; >>>> >>> >>> It is also probably better to check whether shinfo->nr_frags is too >>> large which makes frag_overflow > MAX_SKB_FRAGS. I know skb should be >>> already be valid at this point but it wouldn't hurt to be more careful. >> Ok, I've added this: >> /* At this point shinfo->nr_frags is in fact the number of >> * slots, which can be as large as XEN_NETBK_LEGACY_SLOTS_MAX. >> */ >> + if (shinfo->nr_frags > MAX_SKB_FRAGS) { >> + if (shinfo->nr_frags > XEN_NETBK_LEGACY_SLOTS_MAX) return NULL; >> + frag_overflow = shinfo->nr_frags - MAX_SKB_FRAGS; >> > > What I suggested is > > BUG_ON(frag_overflow > MAX_SKB_FRAGS)
Ok, I've changed it.
Zoli
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