From 36e228354857379beff973352fc174336fec14bc Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Tue, 10 Jan 2017 12:24:01 -0800 Subject: [PATCH] gro: Enter slow-path if there is no tailroom commit 1272ce87fa017ca4cf32920764d879656b7a005a upstream. The GRO path has a fast-path where we avoid calling pskb_may_pull and pskb_expand by directly accessing frag0. However, this should only be done if we have enough tailroom in the skb as otherwise we'll have to expand it later anyway. This patch adds the check by capping frag0_len with the skb tailroom. Fixes: cb18978cbf45 ("gro: Open-code final pskb_may_pull") Reported-by: Slava Shwartsman Signed-off-by: Herbert Xu Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller Signed-off-by: Ben Hutchings --- net/core/dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/net/core/dev.c b/net/core/dev.c index 75be7e226268..b9d6f3dcfc55 100644 --- a/net/core/dev.c +++ b/net/core/dev.c @@ -3920,7 +3920,8 @@ static void skb_gro_reset_offset(struct sk_buff *skb) pinfo->nr_frags && !PageHighMem(skb_frag_page(frag0))) { NAPI_GRO_CB(skb)->frag0 = skb_frag_address(frag0); - NAPI_GRO_CB(skb)->frag0_len = skb_frag_size(frag0); + NAPI_GRO_CB(skb)->frag0_len = min(skb_frag_size(frag0), + skb->end - skb->tail); } }