From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753485AbdK1PC7 (ORCPT ); Tue, 28 Nov 2017 10:02:59 -0500 Received: from mail.kernel.org ([198.145.29.99]:44988 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752726AbdK1PCz (ORCPT ); Tue, 28 Nov 2017 10:02:55 -0500 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D4EBA21996 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Alexander Shishkin , Andrei Vagin , David Ahern , Jiri Olsa , Namhyung Kim , Peter Zijlstra , Vasily Averin , Wang Nan Subject: [PATCH 07/30] perf machine: Guard against NULL in machine__exit() Date: Tue, 28 Nov 2017 12:01:57 -0300 Message-Id: <20171128150220.5064-8-acme@kernel.org> X-Mailer: git-send-email 2.13.6 In-Reply-To: <20171128150220.5064-1-acme@kernel.org> References: <20171128150220.5064-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo A recent fix for 'perf trace' introduced a bug where machine__exit(trace->host) could be called while trace->host was still NULL, so make this more robust by guarding against NULL, just like free() does. The problem happens, for instance, when !root users try to run 'perf trace': [acme@jouet linux]$ trace Error: No permissions to read /sys/kernel/debug/tracing/events/raw_syscalls/sys_(enter|exit) Hint: Try 'sudo mount -o remount,mode=755 /sys/kernel/debug/tracing' perf: Segmentation fault Obtained 7 stack frames. [0x4f1b2e] /lib64/libc.so.6(+0x3671f) [0x7f43a1dd971f] [0x4f3fec] [0x47468b] [0x42a2db] /lib64/libc.so.6(__libc_start_main+0xe9) [0x7f43a1dc3509] [0x42a6c9] Segmentation fault (core dumped) [acme@jouet linux]$ Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andrei Vagin Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Vasily Averin Cc: Wang Nan Fixes: 33974a414ce2 ("perf trace: Call machine__exit() at exit") Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/machine.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c index 6a8d03c3d9b7..270f3223c6df 100644 --- a/tools/perf/util/machine.c +++ b/tools/perf/util/machine.c @@ -172,6 +172,9 @@ void machine__exit(struct machine *machine) { int i; + if (machine == NULL) + return; + machine__destroy_kernel_maps(machine); map_groups__exit(&machine->kmaps); dsos__exit(&machine->dsos); -- 2.13.6