From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stephen Hemminger Subject: Re: [PATCH] sky2: make sure ethernet header is in transmit skb Date: Mon, 4 Jan 2010 08:40:49 -0800 Message-ID: <20100104084049.4d9cd0e4@nehalam> References: <20091226140544.5600b3d1@nehalam> <20091226.194418.229766965.davem@davemloft.net> <20091226.201107.35060733.davem@davemloft.net> <20100103.213258.263977883.davem@davemloft.net> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Cc: mbreuer@majjas.com, akpm@linux-foundation.org, flyboy@gmail.com, linux-kernel@vger.kernel.org, netdev@vger.kernel.org To: David Miller Return-path: In-Reply-To: <20100103.213258.263977883.davem@davemloft.net> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Sun, 03 Jan 2010 21:32:58 -0800 (PST) David Miller wrote: > From: David Miller > Date: Sat, 26 Dec 2009 20:11:07 -0800 (PST) > > > From: David Miller > > Date: Sat, 26 Dec 2009 19:44:18 -0800 (PST) > > > >> From: Stephen Hemminger > >> Date: Sat, 26 Dec 2009 14:05:44 -0800 > >> > >>> Other drivers may have same problem, I really think this ought > >>> to be done at higher level. > >> > >> I tend to agree with you, and I thought we had handled all > >> cases. Let's simply make AF_PACKET linearize the link > >> level header before sending things out to the transmit path. > >> > >> I can work on this if you want. > > > > Actually Stephen, I took a look and I can't see how AF_PACKET > > can create this situation. > > > > It always copies into the linear area of the SKB it allocates > > for sendmsg() processing. Whether the data comes from sendmsg > > data or the mmap() ring buffer. > > Stephen can you get a backtrace of the code path which triggers > this? I want to fix it at a higher level too, but I can't > do that until I know where it actually happens. Ignore it, the problem is outside the sky2 driver in some other place causing corrupt skb's. I never reproduced this (with added BUG_ON and WARN_ON), only seen by Michael.