From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH] net: ethtool: avoid allocation failure for dump_regs Date: Wed, 18 Jan 2017 11:45:05 -0500 (EST) Message-ID: <20170118.114505.1855687422610394730.davem@davemloft.net> References: <1484746445-97920-1-git-send-email-darcari@redhat.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org To: darcari@redhat.com Return-path: Received: from shards.monkeyblade.net ([184.105.139.130]:36060 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752065AbdARQpH (ORCPT ); Wed, 18 Jan 2017 11:45:07 -0500 In-Reply-To: <1484746445-97920-1-git-send-email-darcari@redhat.com> Sender: netdev-owner@vger.kernel.org List-ID: From: David Arcari Date: Wed, 18 Jan 2017 08:34:05 -0500 > If the user executes 'ethtool -d' for an interface and the associated > get_regs_len() function returns 0, the user will see a call trace from > the vmalloc() call in ethtool_get_regs(). This patch modifies > ethtool_get_regs() to avoid the call to vmalloc when the size is zero. > > Signed-off-by: David Arcari I think when the driver indicates this, it is equivalent to saying that the operation isn't supported. Also, this guards us against ->get_regs() methods that don't handle zero length requests properly. I see many which are going to do really terrible things in that situation. Therefore, if get_regs_len() returns zero, treat it the safe as if the ethtool operations were NULL. Thanks.