From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH v2] drivers/net/wan/lapbether: Fixed the value of hard_header_len Date: Mon, 06 Jul 2020 12:16:36 -0700 (PDT) Message-ID: <20200706.121636.148338846008093922.davem@davemloft.net> References: <20200706004521.78091-1-xie.he.0141@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20200706004521.78091-1-xie.he.0141@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: Content-Type: Text/Plain; charset="us-ascii" 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 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.