From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-eopbgr40065.outbound.protection.outlook.com ([40.107.4.65]:2880 "EHLO EUR03-DB5-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S932118AbeCKPPo (ORCPT ); Sun, 11 Mar 2018 11:15:44 -0400 Subject: Re: [PATCH] net/mlx4_en: fix potential use-after-free with dma_unmap_page To: Sarah Newman , Tariq Toukan , Yishai Hadas Cc: netdev@vger.kernel.org References: <1520223607-17560-1-git-send-email-srn@prgmr.com> <1cee1792-52ae-f408-15f0-ee42c1fb2ea3@mellanox.com> <2a726e89-8411-380e-3809-2dd71bceb7a7@prgmr.com> <0b28d134-eec4-4e81-1b26-e05e38fe5605@mellanox.com> <0fb43444-964a-3751-bc2a-1c61e469cc81@prgmr.com> From: Tariq Toukan Message-ID: Date: Sun, 11 Mar 2018 17:15:34 +0200 MIME-Version: 1.0 In-Reply-To: <0fb43444-964a-3751-bc2a-1c61e469cc81@prgmr.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org List-ID: On 06/03/2018 10:16 PM, Sarah Newman wrote: > On 03/06/2018 08:13 AM, Tariq Toukan wrote: > >> I have a general question about the process. >> I don't totally get what branch this patch is targeted to. >> It touches critical areas in datapath and should go through regression tests before it is accepted to any branch. >> > > This one is against 4.9 - > https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux-stable.git/log/?h=linux-4.9.y > > I assume you'd be interested in applying a fix to all currently maintained stable branches between 3.6 to 4.11, per > https://www.kernel.org/category/releases.html . > Yes. > I know of at least one other person whose workaround has been to disable GRO, but I don't understand the networking code well enough to guarantee that > disabling GRO means the problem will never occur under all possible error conditions. If it's guaranteed that disabling GRO will definitely mitigate > the bug, probably it's better to stop supporting GRO for these versions of the driver instead of trying to implement some other fix. I don't think we have a guarantee, it just happens to work. Also, disabling GRO will cause dramatic performance degradation. We should fix this, not WA. > > --Sarah >