From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 93988C433DF for ; Mon, 6 Jul 2020 19:16:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 79C5B206CD for ; Mon, 6 Jul 2020 19:16:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726583AbgGFTQn (ORCPT ); Mon, 6 Jul 2020 15:16:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43956 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725901AbgGFTQm (ORCPT ); Mon, 6 Jul 2020 15:16:42 -0400 Received: from shards.monkeyblade.net (shards.monkeyblade.net [IPv6:2620:137:e000::1:9]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id AE802C061755; Mon, 6 Jul 2020 12:16:42 -0700 (PDT) Received: from localhost (unknown [IPv6:2601:601:9f00:477::3d5]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id B2F151274B9CD; Mon, 6 Jul 2020 12:16:39 -0700 (PDT) Date: Mon, 06 Jul 2020 12:16:36 -0700 (PDT) Message-Id: <20200706.121636.148338846008093922.davem@davemloft.net> To: xie.he.0141@gmail.com Cc: kuba@kernel.org, madhuparnabhowmik04@gmail.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-x25@vger.kernel.org Subject: Re: [PATCH v2] drivers/net/wan/lapbether: Fixed the value of hard_header_len From: David Miller In-Reply-To: <20200706004521.78091-1-xie.he.0141@gmail.com> References: <20200706004521.78091-1-xie.he.0141@gmail.com> X-Mailer: Mew version 6.8 on Emacs 26.3 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Mon, 06 Jul 2020 12:16:39 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Xie He Date: Sun, 5 Jul 2020 17:45:21 -0700 > When this driver transmits data, > first this driver will remove a pseudo header of 1 byte, > then the lapb module will prepend the LAPB header of 2 or 3 bytes, > then this driver will prepend a length field of 2 bytes, > then the underlying Ethernet device will prepend its own header. > > So, the header length required should be: > -1 + 3 + 2 + "the header length needed by the underlying device". > > This patch fixes kernel panic when this driver is used with AF_PACKET > SOCK_DGRAM sockets. > > Signed-off-by: Xie He Applied, thank you.