From 54d27fcb338bd9c42d1dfc5a39e18f6f9d373c2e Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 13 May 2013 21:25:52 +0000 Subject: [PATCH] tcp: fix tcp_md5_hash_skb_data() TCP md5 communications fail [1] for some devices, because sg/crypto code assume page offsets are below PAGE_SIZE. This was discovered using mlx4 driver [2], but I suspect loopback might trigger the same bug now we use order-3 pages in tcp_sendmsg() [1] Failure is giving following messages. huh, entered softirq 3 NET_RX ffffffff806ad230 preempt_count 00000100, exited with 00000101? [2] mlx4 driver uses order-2 pages to allocate RX frags Reported-by: Matt Schnall Signed-off-by: Eric Dumazet Cc: Bernhard Beck Signed-off-by: David S. Miller --- net/ipv4/tcp.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index dcb116dde216..10c93930abda 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -3269,8 +3269,11 @@ int tcp_md5_hash_skb_data(struct tcp_md5sig_pool *hp, for (i = 0; i < shi->nr_frags; ++i) { const struct skb_frag_struct *f = &shi->frags[i]; - struct page *page = skb_frag_page(f); - sg_set_page(&sg, page, skb_frag_size(f), f->page_offset); + unsigned int offset = f->page_offset; + struct page *page = skb_frag_page(f) + (offset >> PAGE_SHIFT); + + sg_set_page(&sg, page, skb_frag_size(f), + offset_in_page(offset)); if (crypto_hash_update(desc, &sg, skb_frag_size(f))) return 1; }