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=-13.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 BBB90C433E0 for ; Thu, 16 Jul 2020 14:39:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A1A55206F4 for ; Thu, 16 Jul 2020 14:39:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728316AbgGPOjJ (ORCPT ); Thu, 16 Jul 2020 10:39:09 -0400 Received: from youngberry.canonical.com ([91.189.89.112]:58226 "EHLO youngberry.canonical.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726963AbgGPOjJ (ORCPT ); Thu, 16 Jul 2020 10:39:09 -0400 Received: from 1.general.cking.uk.vpn ([10.172.193.212] helo=localhost) by youngberry.canonical.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.86_2) (envelope-from ) id 1jw52G-0006r1-D3; Thu, 16 Jul 2020 14:38:56 +0000 From: Colin King To: "Paul E . McKenney" , Josh Triplett , Steven Rostedt , Mathieu Desnoyers , Lai Jiangshan , Joel Fernandes , rcu@vger.kernel.org Cc: kernel-janitors@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH][next] refperf: avoid null pointer dereference when buf fails to allocate Date: Thu, 16 Jul 2020 15:38:56 +0100 Message-Id: <20200716143856.1708123-1-colin.king@canonical.com> X-Mailer: git-send-email 2.27.0 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit Sender: rcu-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Colin Ian King Currently in the unlikely event that buf fails to be allocated it is dereferenced a few times. Use the errexit flag to determine if buf should be written to to avoid the null pointer dereferences. Addresses-Coverity: ("Dereference after null check") Fixes: f518f154ecef ("refperf: Dynamically allocate experiment-summary output buffer") Signed-off-by: Colin Ian King --- kernel/rcu/refscale.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) diff --git a/kernel/rcu/refscale.c b/kernel/rcu/refscale.c index d9291f883b54..952595c678b3 100644 --- a/kernel/rcu/refscale.c +++ b/kernel/rcu/refscale.c @@ -546,9 +546,11 @@ static int main_func(void *arg) // Print the average of all experiments SCALEOUT("END OF TEST. Calculating average duration per loop (nanoseconds)...\n"); - buf[0] = 0; - strcat(buf, "\n"); - strcat(buf, "Runs\tTime(ns)\n"); + if (!errexit) { + buf[0] = 0; + strcat(buf, "\n"); + strcat(buf, "Runs\tTime(ns)\n"); + } for (exp = 0; exp < nruns; exp++) { u64 avg; -- 2.27.0