From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keiichi KII Subject: [PATCH] netconsole: avoid null pointer dereference at show_local_mac() Date: Fri, 15 Feb 2008 18:45:48 +0900 Message-ID: <47B55F4C.5080703@bx.jp.nec.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-2022-JP Content-Transfer-Encoding: 7bit Cc: Satyam Sharma , Linux Kernel Mailing List , Netdev , David Miller , Stephen Hemminger To: Matt Mackall Return-path: Received: from TYO201.gate.nec.co.jp ([202.32.8.193]:41898 "EHLO tyo201.gate.nec.co.jp" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754509AbYBOJqK (ORCPT ); Fri, 15 Feb 2008 04:46:10 -0500 Sender: netdev-owner@vger.kernel.org List-ID: From: Keiichi KII This patch avoids a null pointer dereference when we read local_mac for netconsole in configfs and shows default local mac address value. A null pointer dereference occurs when we call show_local_mac() via local_mac entry in configfs before we setup the content of netpoll using netpoll_setup(). This patch is for 2.6.25-rc1. Your comments are very welcome. Signed-off-by: Keiichi KII --- Index: pre-release/drivers/net/netconsole.c =================================================================== --- pre-release.orig/drivers/net/netconsole.c +++ pre-release/drivers/net/netconsole.c @@ -309,8 +309,8 @@ static ssize_t show_local_mac(struct net struct net_device *dev = nt->np.dev; DECLARE_MAC_BUF(mac); - return snprintf(buf, PAGE_SIZE, "%s\n", - print_mac(mac, dev->dev_addr)); + return snprintf(buf, PAGE_SIZE, "%s\n", dev ? + print_mac(mac, dev->dev_addr) : "ff:ff:ff:ff:ff:ff"); } static ssize_t show_remote_mac(struct netconsole_target *nt, char *buf) -- Keiichi KII NEC Corporation OSS Platform Development Division E-mail: k-keiichi@bx.jp.nec.com