From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Jan Beulich" Subject: Re: [Xen-devel] [PATCH] xen-netfront: pull on receive skb may need to happen earlier Date: Tue, 09 Jul 2013 07:52:31 +0100 Message-ID: <51DBCF4F02000078000E3793@nat28.tlf.novell.com> References: <8511913.uMAmUdIO30@eistomin.edss.local> <20130517085923.GC14401@zion.uk.xensource.com> <51D57C1F.8070909@hunenet.nl> <20130704150137.GW7483@zion.uk.xensource.com> <51D6AED902000078000E2EA9@nat28.tlf.novell.com> <20130705145319.GB9050@zion.uk.xensource.com> <51DAA9B202000078000E3357@nat28.tlf.novell.com> <51DAE6CA02000078000E3566@nat28.tlf.novell.com> <20130708154814.GI8027@zion.uk.xensource.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Cc: "Ian Campbell" , , "Dion Kant" , , , To: "Wei Liu" Return-path: In-Reply-To: <20130708154814.GI8027@zion.uk.xensource.com> Content-Disposition: inline Sender: stable-owner@vger.kernel.org List-Id: netdev.vger.kernel.org >>> On 08.07.13 at 17:48, Wei Liu wrote: > On Mon, Jul 08, 2013 at 03:20:26PM +0100, Jan Beulich wrote: >> @@ -1014,7 +1025,7 @@ err: >> >> skb_shinfo(skb)->frags[0].page_offset = rx->offset; >> skb_frag_size_set(&skb_shinfo(skb)->frags[0], rx->status); >> - skb->data_len = rx->status; >> + skb->len = skb->data_len = rx->status; > > This is not correct. You should not be needing this. Now you lose count > of SKB head len. Try to go without the above line and see if it makes a > difference? I don't follow - at this point, there's 0 bytes of head (this only changes with the first call to __pskb_pull_tail()). Hence ->len == ->data_len seems correct to me (and afaict pulling would do the wrong thing if I dropped that change). Jan