From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from exchange.solarflare.com ([216.237.3.220]:5345 "EHLO exchange.solarflare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751419Ab1GURyL (ORCPT ); Thu, 21 Jul 2011 13:54:11 -0400 Subject: [PATCH net-2.6] ethtool: Allow zero-length register dumps again From: Ben Hutchings To: David Miller Cc: "John W. Linville" , Kalle Valo , netdev@vger.kernel.org, linux-wireless@vger.kernel.org In-Reply-To: <1311270409.28569.32.camel@localhost> References: <20110720091850.32210.2059.stgit@localhost6.localdomain6> <1311161889.1041.11.camel@localhost> <4E26C2DC.8090208@qca.qualcomm.com> <20110720143611.GA18231@tuxdriver.com> <1311270409.28569.32.camel@localhost> Content-Type: text/plain; charset="UTF-8" Date: Thu, 21 Jul 2011 19:54:00 +0200 Message-ID: <1311270840.28569.34.camel@localhost> (sfid-20110721_195417_011929_3E38E2E5) Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: Some drivers (ab)use the ethtool_ops::get_regs operation to expose only a hardware revision ID. Commit a77f5db361ed9953b5b749353ea2c7fed2bf8d93 ('ethtool: Allocate register dump buffer with vmalloc()') had the side-effect of breaking these, as vmalloc() returns a null pointer for size=0 whereas kmalloc() did not. For backward-compatibility, allow zero-length dumps again. Reported-by: Kalle Valo Signed-off-by: Ben Hutchings Cc: stable@kernel.org [2.6.37+] --- This is compile-tested only. I'm on vacation, damnit. Ben. net/core/ethtool.c | 4 ++-- 1 files changed, 2 insertions(+), 2 deletions(-) diff --git a/net/core/ethtool.c b/net/core/ethtool.c index fd14116..4fb7704 100644 --- a/net/core/ethtool.c +++ b/net/core/ethtool.c @@ -1227,7 +1227,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) regs.len = reglen; regbuf = vzalloc(reglen); - if (!regbuf) + if (reglen && !regbuf) return -ENOMEM; ops->get_regs(dev, ®s, regbuf); @@ -1236,7 +1236,7 @@ static int ethtool_get_regs(struct net_device *dev, char __user *useraddr) if (copy_to_user(useraddr, ®s, sizeof(regs))) goto out; useraddr += offsetof(struct ethtool_regs, data); - if (copy_to_user(useraddr, regbuf, regs.len)) + if (regbuf && copy_to_user(useraddr, regbuf, regs.len)) goto out; ret = 0; -- 1.7.5.4 -- Ben Hutchings, Senior Software Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.