From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by dpdk.org (Postfix) with ESMTP id 49A7B6CD8; Thu, 31 Jan 2019 16:57:57 +0100 (CET) Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 2307BC03D47D; Thu, 31 Jan 2019 15:57:56 +0000 (UTC) Received: from ktraynor.remote.csb (ovpn-117-200.ams2.redhat.com [10.36.117.200]) by smtp.corp.redhat.com (Postfix) with ESMTP id 30BDA5C207; Thu, 31 Jan 2019 15:57:52 +0000 (UTC) To: "Burakov, Anatoly" , Thomas Monjalon Cc: dev@dpdk.org, Bruce Richardson , ferruh.yigit@intel.com, andy01011501@163.com, Yongseok Koh , "stable@dpdk.org" References: <4e041e83fb00d8d818682997f795928c36b3283a.1547127516.git.anatoly.burakov@intel.com> <1614490.ZEn2XMpOzn@xps> From: Kevin Traynor Organization: Red Hat Message-ID: Date: Thu, 31 Jan 2019 15:57:51 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.2.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Thu, 31 Jan 2019 15:57:56 +0000 (UTC) Subject: Re: [dpdk-dev] [PATCH] eal: fix strdup usages in internal config X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 31 Jan 2019 15:57:57 -0000 On 01/31/2019 03:55 PM, Burakov, Anatoly wrote: > On 31-Jan-19 3:04 PM, Thomas Monjalon wrote: >> 31/01/2019 15:15, Kevin Traynor: >>> On 01/31/2019 02:10 PM, Burakov, Anatoly wrote: >>>> On 31-Jan-19 11:21 AM, Kevin Traynor wrote: >>>>> On 01/10/2019 01:38 PM, Anatoly Burakov wrote: >>>>>> Currently, we use strdup in a few places to store command-line >>>>>> parameter values for certain internal config values. There are >>>>>> several issues with that. >>>>>> >>>>>> First of all, they're never freed, so memory ends up leaking >>>>>> either after EAL exit, or when these command-line options are >>>>>> supplied multiple times. >>>>>> >>>>>> Second of all, they're defined as `const char *`, so they >>>>>> *cannot* be freed even if we wanted to. >>>>>> >>>>>> Finally, strdup may return NULL, which will be stored in the >>>>>> config. For most fields, NULL is a valid value, but for the >>>>>> default prefix, the value is always expected to be valid. >>>>>> >>>>>> To fix all of this, three things are done. First, we change >>>>>> the definitions of these values to `char *` as opposed to >>>>>> `const char *`. This does not break the ABI, and previous >>>>>> code assumes constness (which is more restrictive), so it's >>>>>> safe to do so. >>>>>> >>>>>> Then, fix all usages of strdup to check return value, and add >>>>>> a cleanup function that will free the memory occupied by >>>>>> these strings, as well as freeing them before assigning a new >>>>>> value to prevent leaks when parameter is specified multiple >>>>>> times. >>>>>> >>>>>> And finally, add an internal API to query hugefile prefix, so >>>>>> that, absent of a valid value, a default value will be >>>>>> returned, and also fix up all usages of hugefile prefix to >>>>>> use this API instead of accessing hugefile prefix directly. >>>>>> >>>>>> Bugzilla ID: 108 >>>>>> >>>>> >>>>> Hi Anatoly - this doesn't have stable or Fixes tags, but the bugzilla >>>>> was reported on 17.11. Is it for backport to stable branches? >>>>> >>>> >>>> It can be. Whether it's worth the effort of backporting is not my >>>> call :) >>>> >>> >>> It's fine for 18.11 branch anyway, just needed a little help due to some >>> changed context. I will send diff to stable list as normal. >> >> Nothing was broken. I see it like an improvement. >> Not sure it is worth the effort. >> > > Well, *technically*, there was a memory leak. For example, if you > specify mbuf pool ops flag multiple times, previously allocated strdup() > call results would be discarded and leaked. > > However, it's such a minor issue that it's indeed likely not worth the > effort. > > It's already done - just sent it in the batch a few mins ago