From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mga01.intel.com (mga01.intel.com [192.55.52.88]) by dpdk.org (Postfix) with ESMTP id C8DF41B129; Thu, 31 Jan 2019 16:55:10 +0100 (CET) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 31 Jan 2019 07:55:09 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,545,1539673200"; d="scan'208";a="122903841" Received: from aburakov-mobl1.ger.corp.intel.com (HELO [10.237.220.94]) ([10.237.220.94]) by orsmga003.jf.intel.com with ESMTP; 31 Jan 2019 07:55:07 -0800 To: Thomas Monjalon , Kevin Traynor 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: "Burakov, Anatoly" Message-ID: Date: Thu, 31 Jan 2019 15:55:06 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.4.0 MIME-Version: 1.0 In-Reply-To: <1614490.ZEn2XMpOzn@xps> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit 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 15:55:11 -0000 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. -- Thanks, Anatoly