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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 7DA6BC43142 for ; Tue, 26 Jun 2018 06:52:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 41C5324F13 for ; Tue, 26 Jun 2018 06:52:58 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 41C5324F13 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=zytor.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752240AbeFZGw4 (ORCPT ); Tue, 26 Jun 2018 02:52:56 -0400 Received: from terminus.zytor.com ([198.137.202.136]:58181 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751134AbeFZGwy (ORCPT ); Tue, 26 Jun 2018 02:52:54 -0400 Received: from terminus.zytor.com (localhost [127.0.0.1]) by terminus.zytor.com (8.15.2/8.15.2) with ESMTPS id w5Q6qlYr1591165 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO); Mon, 25 Jun 2018 23:52:47 -0700 Received: (from tipbot@localhost) by terminus.zytor.com (8.15.2/8.15.2/Submit) id w5Q6qlON1591162; Mon, 25 Jun 2018 23:52:47 -0700 Date: Mon, 25 Jun 2018 23:52:47 -0700 X-Authentication-Warning: terminus.zytor.com: tipbot set sender to tipbot@zytor.com using -f From: tip-bot for Sandipan Das Message-ID: Cc: mingo@kernel.org, linux-kernel@vger.kernel.org, jolsa@redhat.com, sukadev@linux.vnet.ibm.com, ravi.bangoria@linux.ibm.com, sandipan@linux.ibm.com, hpa@zytor.com, naveen.n.rao@linux.vnet.ibm.com, tglx@linutronix.de, acme@redhat.com Reply-To: linux-kernel@vger.kernel.org, jolsa@redhat.com, ravi.bangoria@linux.ibm.com, sukadev@linux.vnet.ibm.com, hpa@zytor.com, sandipan@linux.ibm.com, mingo@kernel.org, acme@redhat.com, naveen.n.rao@linux.vnet.ibm.com, tglx@linutronix.de In-Reply-To: <20180611104049.11048-1-sandipan@linux.ibm.com> References: <20180611104049.11048-1-sandipan@linux.ibm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf report powerpc: Fix crash if callchain is empty Git-Commit-ID: 143c99f6ac6812d23254e80844d6e34be897d3e1 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 143c99f6ac6812d23254e80844d6e34be897d3e1 Gitweb: https://git.kernel.org/tip/143c99f6ac6812d23254e80844d6e34be897d3e1 Author: Sandipan Das AuthorDate: Mon, 11 Jun 2018 16:10:49 +0530 Committer: Arnaldo Carvalho de Melo CommitDate: Mon, 25 Jun 2018 11:59:35 -0300 perf report powerpc: Fix crash if callchain is empty For some cases, the callchain provided by the kernel may be empty. So, the callchain ip filtering code will cause a crash if we do not check whether the struct ip_callchain pointer is NULL before accessing any members. This can be observed on a powerpc64le system running Fedora 27 as shown below. # perf record -b -e cycles:u ls Before: # perf report --branch-history perf: Segmentation fault -------- backtrace -------- perf[0x1027615c] linux-vdso64.so.1(__kernel_sigtramp_rt64+0x0)[0x7fff856304d8] perf(arch_skip_callchain_idx+0x44)[0x10257c58] perf[0x1017f2e4] perf(thread__resolve_callchain+0x124)[0x1017ff5c] perf(sample__resolve_callchain+0xf0)[0x10172788] ... After: # perf report --branch-history Samples: 25 of event 'cycles:u', Event count (approx.): 2306870 Overhead Source:Line Symbol Shared Object + 11.60% _init+35736 [.] _init ls + 9.84% strcoll_l.c:137 [.] __strcoll_l libc-2.26.so + 9.16% memcpy.S:175 [.] __memcpy_power7 libc-2.26.so + 9.01% gconv_charset.h:54 [.] _nl_find_locale libc-2.26.so + 8.87% dl-addr.c:52 [.] _dl_addr libc-2.26.so + 8.83% _init+236 [.] _init ls ... Reported-by: Ravi Bangoria Signed-off-by: Sandipan Das Acked-by: Ravi Bangoria Cc: Jiri Olsa Cc: Naveen N. Rao Cc: Sukadev Bhattiprolu Link: http://lkml.kernel.org/r/20180611104049.11048-1-sandipan@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/arch/powerpc/util/skip-callchain-idx.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/perf/arch/powerpc/util/skip-callchain-idx.c b/tools/perf/arch/powerpc/util/skip-callchain-idx.c index 3598b8b75d27..ef5d59a5742e 100644 --- a/tools/perf/arch/powerpc/util/skip-callchain-idx.c +++ b/tools/perf/arch/powerpc/util/skip-callchain-idx.c @@ -243,7 +243,7 @@ int arch_skip_callchain_idx(struct thread *thread, struct ip_callchain *chain) u64 ip; u64 skip_slot = -1; - if (chain->nr < 3) + if (!chain || chain->nr < 3) return skip_slot; ip = chain->ips[2];