From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DAA5FA372A for ; Wed, 16 Oct 2019 10:59:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 22A7121848 for ; Wed, 16 Oct 2019 10:59:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2404707AbfJPK7L (ORCPT ); Wed, 16 Oct 2019 06:59:11 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:33390 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726083AbfJPK7L (ORCPT ); Wed, 16 Oct 2019 06:59:11 -0400 Received: from DGGEMS404-HUB.china.huawei.com (unknown [172.30.72.58]) by Forcepoint Email with ESMTP id 453AB4BF490C4069A344; Wed, 16 Oct 2019 18:59:09 +0800 (CST) Received: from [127.0.0.1] (10.177.251.225) by DGGEMS404-HUB.china.huawei.com (10.3.19.204) with Microsoft SMTP Server id 14.3.439.0; Wed, 16 Oct 2019 18:59:01 +0800 Subject: Re: [PATCH] perf jevents: Fix resource leak in process_mapfile() To: John Garry , , , , , , , , , , , CC: , , References: <87e66585-1564-3523-59f6-cab15b7e1717@huawei.com> From: Yunfeng Ye Message-ID: <0cd0d259-e806-effd-5e44-fccd13842697@huawei.com> Date: Wed, 16 Oct 2019 18:58:36 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:60.0) Gecko/20100101 Thunderbird/60.6.1 MIME-Version: 1.0 In-Reply-To: <87e66585-1564-3523-59f6-cab15b7e1717@huawei.com> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 8bit X-Originating-IP: [10.177.251.225] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/10/16 18:40, John Garry wrote: > On 16/10/2019 08:47, Yunfeng Ye wrote: >> There are memory leaks and file descriptor resource leaks in >> process_mapfile(). >> >> Fix this by adding free() and fclose() on the error paths. >> >> Fixes: 80eeb67fe577 ("perf jevents: Program to convert JSON file") >> Signed-off-by: Yunfeng Ye >> --- >>  tools/perf/pmu-events/jevents.c | 9 +++++++-- >>  1 file changed, 7 insertions(+), 2 deletions(-) >> >> diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c >> index e2837260ca4d..6e60d4cff592 100644 >> --- a/tools/perf/pmu-events/jevents.c >> +++ b/tools/perf/pmu-events/jevents.c >> @@ -758,6 +758,7 @@ static int process_mapfile(FILE *outfp, char *fpath) >>      char *line, *p; >>      int line_num; >>      char *tblname; >> +    int ret = 0; >> >>      pr_info("%s: Processing mapfile %s\n", prog, fpath); >> >> @@ -769,6 +770,7 @@ static int process_mapfile(FILE *outfp, char *fpath) >>      if (!mapfp) { >>          pr_info("%s: Error %s opening %s\n", prog, strerror(errno), >>                  fpath); >> +        free(line); >>          return -1; >>      } >> >> @@ -795,7 +797,8 @@ static int process_mapfile(FILE *outfp, char *fpath) >>              /* TODO Deal with lines longer than 16K */ >>              pr_info("%s: Mapfile %s: line %d too long, aborting\n", >>                      prog, fpath, line_num); >> -            return -1; >> +            ret = -1; >> +            goto out; > > There's a subtle change of behaviour here, i.e. now calling print_mapping_table_suffix(), but I don't think that it makes any difference. > yes, I know that "goto out" will run print_mapping_table_suffix(outfp), because the error path before is done like this. so I think it should be use "goto out" to run run print_mapping_table_suffix(outfp). > However, does outfp remain open also in this case: > Because it has a comment that "Make build fail", so I am not handle the outfp, only modify the process_mapfile() function. > main(int argc, char *argv[]) > { > ... > > if (process_mapfile(eventsfp, mapfile)) { >     pr_info("%s: Error processing mapfile %s\n", prog, mapfile); >     /* Make build fail */ >     return 1; > } > > return 0; > > empty_map: >     fclose(eventsfp); >     ... > } > > I think that this code works on the basis that the program exits on any sort of error and releases resources automatically. Having said that, it is a good practice to tidy up. > I agree with you, when program exits, it will releases resources automatically. It's just to make the program clearer and more correct. > John > >>          } >>          line[strlen(line)-1] = '\0'; >> >> @@ -825,7 +828,9 @@ static int process_mapfile(FILE *outfp, char *fpath) >> >>  out: >>      print_mapping_table_suffix(outfp); >> -    return 0; >> +    fclose(mapfp); >> +    free(line); >> +    return ret; >>  } >> >>  /* >> > > > > . >