From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752976AbcG2OH6 (ORCPT ); Fri, 29 Jul 2016 10:07:58 -0400 Received: from mail-pa0-f66.google.com ([209.85.220.66]:34537 "EHLO mail-pa0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751458AbcG2OH4 (ORCPT ); Fri, 29 Jul 2016 10:07:56 -0400 Subject: Re: [PATCH v3] perf sched: fix wrong conversion of task state To: Tomoki Sekiyama , linux-kernel@vger.kernel.org References: <1469764808-26348-1-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: <27bff7e4-e25d-69bd-8a3c-1c100c7093f8@gmail.com> Date: Fri, 29 Jul 2016 08:07:54 -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: <1469764808-26348-1-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 7/28/16 10:00 PM, Tomoki Sekiyama wrote: > sched_out_state() converts the prev_state u64 bitmask to a char in > a wrong way, which may cause invalid memory access. > TASK_STATE_TO_CHAR_STR should also be fixed to adapt current > kernel's sched.h. Masami's point is that this should be 2 separate patches -- as suggested by the 'also' in the description. > > Signed-off-by: Tomoki Sekiyama > Cc: Jiri Olsa > Cc: David Ahern > Cc: Namhyung Kim > Cc: Peter Zijlstra > Cc: Masami Hiramatsu > --- > tools/perf/builtin-sched.c | 7 ++++--- > 1 file changed, 4 insertions(+), 3 deletions(-) > > diff --git a/tools/perf/builtin-sched.c b/tools/perf/builtin-sched.c > index 0dfe8df..5776263 100644 > --- a/tools/perf/builtin-sched.c > +++ b/tools/perf/builtin-sched.c > @@ -70,7 +70,7 @@ struct sched_atom { > struct task_desc *wakee; > }; > > -#define TASK_STATE_TO_CHAR_STR "RSDTtZXxKWP" > +#define TASK_STATE_TO_CHAR_STR "RSDTtXZxKWPNn" Patch 1 updates this macro to latest kernel version. > > enum thread_state { > THREAD_SLEEPING = 0, > @@ -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 > Patch 2 fixes access to str by treating prev_state as a bitmask and adding the Fixes: Fixes: cdce9d738b91e ("perf sched: Add sched latency profiling")