From 21df56c6e2372e09c916111efb6c14c372a5ab2e Mon Sep 17 00:00:00 2001 From: Herbert Xu Date: Sun, 18 Nov 2007 18:48:08 -0800 Subject: [PATCH] [TCP]: Fix TCP header misalignment Indeed my previous change to alloc_pskb has made it possible for the TCP header to be misaligned iff the MTU is not a multiple of 4 (and less than a page). So I suspect the optimised IPsec MTU calculation is giving you just such an MTU :) This patch fixes it by changing alloc_pskb to make sure that the size is at least 32-bit aligned. This does not cause the problem fixed by the previous patch because max_header is always 32-bit aligned which means that in the SG/NOTSO case this will be a no-op. I thought about putting this in the callers but all the current callers are from TCP. If and when we get a non-TCP caller we can always create a TCP wrapper for this function and move the alignment over there. Signed-off-by: Herbert Xu Signed-off-by: David S. Miller --- include/net/sock.h | 3 +++ 1 file changed, 3 insertions(+) diff --git a/include/net/sock.h b/include/net/sock.h index 567e468d7492..67e35c7e230c 100644 --- a/include/net/sock.h +++ b/include/net/sock.h @@ -1236,6 +1236,9 @@ static inline struct sk_buff *sk_stream_alloc_pskb(struct sock *sk, { struct sk_buff *skb; + /* The TCP header must be at least 32-bit aligned. */ + size = ALIGN(size, 4); + skb = alloc_skb_fclone(size + sk->sk_prot->max_header, gfp); if (skb) { skb->truesize += mem; -- 2.20.1