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=-12.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A, 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 4003DC433E2 for ; Tue, 8 Sep 2020 19:18:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 12E7C21D46 for ; Tue, 8 Sep 2020 19:18:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732009AbgIHTS3 (ORCPT ); Tue, 8 Sep 2020 15:18:29 -0400 Received: from mga02.intel.com ([134.134.136.20]:59407 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731142AbgIHQCw (ORCPT ); Tue, 8 Sep 2020 12:02:52 -0400 IronPort-SDR: po/k/mVz/rKQaNpunDFGyqwHb7oftmN3x2KIS4nbF4kaHt0gr1UPXQFvpe6SXoijBbRbG+rTUl bDB2wMf4hAtQ== X-IronPort-AV: E=McAfee;i="6000,8403,9738"; a="145860470" X-IronPort-AV: E=Sophos;i="5.76,406,1592895600"; d="scan'208";a="145860470" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Sep 2020 07:41:11 -0700 IronPort-SDR: GwGJVhQl5LsZCtYfS7A9iPjpGOoLjIqPKg8jU0lNh+QzaUUg/j/tOkU/84RoXAzvNqvUBXGq2n hbejdvwrRCjQ== X-IronPort-AV: E=Sophos;i="5.76,406,1592895600"; d="scan'208";a="480050658" Received: from dpdesmon-mobl1.amr.corp.intel.com (HELO [10.212.58.192]) ([10.212.58.192]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Sep 2020 07:41:03 -0700 Subject: Re: [PATCH] tracing: fix double free To: trix@redhat.com, rostedt@goodmis.org, mingo@redhat.com, natechancellor@gmail.com, ndesaulniers@google.com, baohong.liu@intel.com Cc: linux-kernel@vger.kernel.org, clang-built-linux@googlegroups.com References: <20200907135845.15804-1-trix@redhat.com> From: "Zanussi, Tom" Message-ID: <84df7ef3-0a36-0929-3fa9-74ab773ca12e@linux.intel.com> Date: Tue, 8 Sep 2020 09:41:01 -0500 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.12.0 MIME-Version: 1.0 In-Reply-To: <20200907135845.15804-1-trix@redhat.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-GB Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Tom, On 9/7/2020 8:58 AM, trix@redhat.com wrote: > From: Tom Rix > > clang static analyzer reports this problem > > trace_events_hist.c:3824:3: warning: Attempt to free > released memory > kfree(hist_data->attrs->var_defs.name[i]); > > In parse_var_defs() if there is a problem allocating > var_defs.expr, the earlier var_defs.name is freed. > This free is duplicated by free_var_defs() which frees > the rest of the list. > > Because free_var_defs() has to run anyway, remove the > second free fom parse_var_defs(). > > Fixes: 30350d65ac56 ("tracing: Add variable support to hist triggers") > Signed-off-by: Tom Rix Good catch, thanks for fixing this! Reviewed-by: Tom Zanussi > --- > kernel/trace/trace_events_hist.c | 1 - > 1 file changed, 1 deletion(-) > > diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c > index 0b933546142e..1b2ef6490229 100644 > --- a/kernel/trace/trace_events_hist.c > +++ b/kernel/trace/trace_events_hist.c > @@ -3865,7 +3865,6 @@ static int parse_var_defs(struct hist_trigger_data *hist_data) > > s = kstrdup(field_str, GFP_KERNEL); > if (!s) { > - kfree(hist_data->attrs->var_defs.name[n_vars]); > ret = -ENOMEM; > goto free; > } >