From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Fri, 2 Aug 2013 10:04:44 +0200 From: Linus =?utf-8?Q?L=C3=BCssing?= Message-ID: <20130802080444.GA25436@Linus-Debian> References: <1374888285-20775-1-git-send-email-linus.luessing@web.de> <1374888285-20775-2-git-send-email-linus.luessing@web.de> <201308021205.28767.lindner_marek@yahoo.de> <20130802071806.GE3936@ritirata.org> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20130802071806.GE3936@ritirata.org> Subject: Re: [B.A.T.M.A.N.] [PATCH next 2/2] batman-adv: fix potential kernel paging error for unicast transmissions Reply-To: The list for a Better Approach To Mobile Ad-hoc Networking List-Id: The list for a Better Approach To Mobile Ad-hoc Networking List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: The list for a Better Approach To Mobile Ad-hoc Networking On Fri, Aug 02, 2013 at 09:18:06AM +0200, Antonio Quartulli wrote: > On Fri, Aug 02, 2013 at 12:05:28PM +0800, Marek Lindner wrote: > > On Monday, July 29, 2013 04:17:57 Antonio Quartulli wrote: > > > Il 27.07.2013 03:24 Linus Lüssing ha scritto: > > > > batadv_send_skb_prepare_unicast(_4addr) might reallocate the skb's > > > > data. If it does then our ethhdr pointer is not valid anymore in > > > > batadv_send_skb_unicast(), resulting in a kernel paging error. > > > > > > > > This patch fixes this issue by storing the few bytes we are interested > > > > in on the stack before modifying the skb. > > > > > > Good fix! thanks! > > > > > > > > > However, I think it would be nice to send another patch aiming master > > > which could polish this situation a bit better: e.g. by calling > > > skb_reset_mac_header() in the batadv_send_skb_prepare_unicast_* > > > functions and then get the Ethernet header with eth_hdr() right after > > > having changed the skb. > > > > I like that approach because it seems cleaner that way. Is there a reason not > > do it right away ? > > I thought the second approach would consist in a bigger patch and so I preferred > to send this to net and the bigger patch to net-next later. > > But you may be right. The change I suggested is not really big. > Linus, would you like to provide "the next" patch so that we can clearly > understand if it is worth sending to net or not? Sure! I think it could actually be a lot easier than I thought (if I didn't misread or miss something in the skb code). > > Cheers, > > -- > Antonio Quartulli > > ..each of us alone is worth nothing.. > Ernesto "Che" Guevara