From: Eric Dumazet <eduma...@google.com> Imagine initial value of max_skb_frags is 17, and last skb in write queue has 15 frags.
Then max_skb_frags is lowered to 14 or smaller value. tcp_sendmsg() will then be allowed to add additional page frags and eventually go past MAX_SKB_FRAGS, overflowing struct skb_shared_info. Fixes: 5f74f82ea34c ("net:Add sysctl_max_skb_frags") Signed-off-by: Eric Dumazet <eduma...@google.com> Cc: Hans Westgaard Ry <hans.westgaard...@oracle.com> Cc: HÃ¥kon Bugge <haakon.bu...@oracle.com> --- net/ipv4/tcp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3251fe71f39f..18238ef8135a 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1241,7 +1241,7 @@ int tcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t size) if (!skb_can_coalesce(skb, i, pfrag->page, pfrag->offset)) { - if (i == sysctl_max_skb_frags || !sg) { + if (i >= sysctl_max_skb_frags || !sg) { tcp_mark_push(tp, skb); goto new_segment; }