From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751490Ab0IHE5h (ORCPT ); Wed, 8 Sep 2010 00:57:37 -0400 Received: from [83.228.35.12] ([83.228.35.12]:53223 "EHLO fs.ru.acad.bg" rhost-flags-FAIL-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1751167Ab0IHE5e (ORCPT ); Wed, 8 Sep 2010 00:57:34 -0400 Message-ID: <4C8717BB.2050504@fs.uni-ruse.bg> Date: Wed, 08 Sep 2010 07:57:31 +0300 From: Plamen Petrov User-Agent: Mozilla/5.0 (Windows; U; Windows NT 5.1; bg; rv:1.9.1.11) Gecko/20100711 Thunderbird/3.0.6 MIME-Version: 1.0 To: Eric Dumazet CC: Jarek Poplawski , Herbert Xu , "Rafael J. Wysocki" , Kernel Testers List , Maciej Rutecki , "David S. Miller" , Linux Kernel Mailing List , netdev@vger.kernel.org Subject: Re: [Bug #16626] Machine hangs with EIP at skb_copy_and_csum_dev References: <20100904203429.GA4891@del.dom.local> <1283672983.3402.38.camel@edumazet-laptop> In-Reply-To: <1283672983.3402.38.camel@edumazet-laptop> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org На 05.9.2010 г. 10:49, Eric Dumazet написа: > Le samedi 04 septembre 2010 à 22:34 +0200, Jarek Poplawski a écrit : > >> Hi again, >> >> Just had a second look, and unless I miss something... >> >> Plamen, could you test this patch, too? (Without removing the previous >> one.) >> >> Thanks, >> Jarek P. >> >> -------------------> >> >> [PATCH] gro: Re-fix different skb headrooms >> >> The patch: "gro: fix different skb headrooms" in its part: >> "2) allocate a minimal skb for head of frag_list" is buggy. The copied >> skb has p->data set at the ip header at the moment, and skb_gro_offset >> is the length of ip + tcp headers. So, after the change the length of >> mac header is skipped. Later skb_set_mac_header() sets it into the >> NET_SKB_PAD area (if it's long enough) and ip header is misaligned at >> NET_SKB_PAD + NET_IP_ALIGN offset. There is no reason to assume the >> original skb was wrongly allocated, so let's copy it as it was. >> >> bugzilla : https://bugzilla.kernel.org/show_bug.cgi?id=16626 >> fixes commit: 3d3be4333fdf6faa080947b331a6a19bce1a4f57 >> >> Reported-by: Plamen Petrov >> Signed-off-by: Jarek Poplawski >> CC: Eric Dumazet >> --- >> >> diff --git a/net/core/skbuff.c b/net/core/skbuff.c >> index 26396ff..c83b421 100644 >> --- a/net/core/skbuff.c >> +++ b/net/core/skbuff.c >> @@ -2706,7 +2706,7 @@ int skb_gro_receive(struct sk_buff **head, struct sk_buff *skb) >> } else if (skb_gro_len(p) != pinfo->gso_size) >> return -E2BIG; >> >> - headroom = NET_SKB_PAD + NET_IP_ALIGN; >> + headroom = skb_headroom(p); >> nskb = alloc_skb(headroom + skb_gro_offset(p), GFP_ATOMIC); >> if (unlikely(!nskb)) >> return -ENOMEM; > > You are right, thanks for reviewing this patch again :) > > By the way, NET_IP_ALIGN is now 0 on x86, so technically speaking, your > patch un-aligns IP header on x86, but thats OK, since other arches might > want it being aligned, while x86 doesnt care. > > Acked-by: Eric Dumazet > > > Well, now that I'm back at work, I'm glad to report that I tested both variants of the patch, and as Eric points out - it works both ways. So, which ever fits you guys better. Thanks a lot!