From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753891AbcHANzK (ORCPT ); Mon, 1 Aug 2016 09:55:10 -0400 Received: from mail-io0-f195.google.com ([209.85.223.195]:36626 "EHLO mail-io0-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751452AbcHANyI (ORCPT ); Mon, 1 Aug 2016 09:54:08 -0400 Subject: Re: [PATCH 1/2 v4] perf sched: fix wrong conversion of task state To: Tomoki Sekiyama , linux-kernel@vger.kernel.org References: <1470025826-8813-1-git-send-email-tomoki.sekiyama.qu@hitachi.com> Cc: ltc-kernel@rdgml.intra.hitachi.co.jp, masumi.moritani.ju@hitachi.com, Jiri Olsa , Namhyung Kim , Peter Zijlstra , Masami Hiramatsu From: David Ahern Message-ID: Date: Mon, 1 Aug 2016 07:52:24 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.11; rv:45.0) Gecko/20100101 Thunderbird/45.2.0 MIME-Version: 1.0 In-Reply-To: <1470025826-8813-1-git-send-email-tomoki.sekiyama.qu@hitachi.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 7/31/16 10:30 PM, Tomoki Sekiyama wrote: > Currently sched_out_state() converts the prev_state u64 bitmask to a char > using the bitmask as an index, which may cause invalid memory access. > This fixes the issue by using the __ffs() returned value as an index. > > Signed-off-by: Tomoki Sekiyama > Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling") > Cc: Jiri Olsa > Cc: David Ahern > Cc: Namhyung Kim > Cc: Peter Zijlstra > Cc: Masami Hiramatsu > --- > Changes from v3: > Added Fixes: > Split the patch into 2 pieces. > > tools/perf/builtin-sched.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c > index 0dfe8df..ce9bef6 100644 > --- a/tools/perf/builtin-sched.c > +++ b/tools/perf/builtin-sched.c > @@ -897,9 +897,10 @@ static int thread_atoms_insert(struct perf_sched *sched, struct thread *thread) > > static char sched_out_state(u64 prev_state) > { > - const char *str = TASK_STATE_TO_CHAR_STR; > + const char str[] = TASK_STATE_TO_CHAR_STR; > + unsigned int bit = prev_state ? __ffs(prev_state) + 1 : 0; > > - return str[prev_state]; > + return bit < ARRAY_SIZE(str) - 1 ? str[bit] : '?'; > } > > static int > Acked-by: David Ahern