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=-9.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3F5E9C43381 for ; Mon, 18 Feb 2019 13:45:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0E7A721900 for ; Mon, 18 Feb 2019 13:45:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550497532; bh=n9g7DiLvsDGRL//KtI0LDtHCc11JJTMqOaOEEX4sirQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=Ep7xcvlvjLh2ufkJSvl2i37zpr3mdSxRJu78BNf/r6BGYdLSIhiMObMaxQToe/25x j7HTYA/MFjWftInKXHBnYPhgOJJhDTloB0PtR8dfCCAvEl/qAWwfkWDZLKBtoefIrC UaUxpI+SlRlNQPWS3G0uHlmPFZdD+FrtYbRc8mdQ= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730664AbfBRNpa (ORCPT ); Mon, 18 Feb 2019 08:45:30 -0500 Received: from mail.kernel.org ([198.145.29.99]:51576 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731340AbfBRNp2 (ORCPT ); Mon, 18 Feb 2019 08:45:28 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.ziggo.nl [83.86.89.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id AA6CE218FC; Mon, 18 Feb 2019 13:45:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1550497527; bh=n9g7DiLvsDGRL//KtI0LDtHCc11JJTMqOaOEEX4sirQ=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=qbXtPvNtMfoVAT/Y5cJAxFmeKZFIz5OI1UukMTT3IioVbP5hm8K6nT2OXOpND/frI 26BI6GBbI7W8+yGBz1W2RLkrkgHD2k+BZ0A+7+wzUyS2EagksM1rP7lQ+wKYZKugdx +EX6AmHywajDzYU3efJSf+Z+c0NmVRArD+NIbtUo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Jin Yao , Jiri Olsa , Arnaldo Carvalho de Melo , Alexander Shishkin , Andi Kleen , Kan Liang , Peter Zijlstra , Sasha Levin Subject: [PATCH 4.20 06/92] perf stat: Fix endless wait for child process Date: Mon, 18 Feb 2019 14:42:09 +0100 Message-Id: <20190218133455.188837879@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190218133454.668268457@linuxfoundation.org> References: <20190218133454.668268457@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 4.20-stable review patch. If anyone has any objections, please let me know. ------------------ [ Upstream commit 8a99255a50c0b4c2a449b96fd8d45fcc8d72c701 ] We hit a 'perf stat' issue by using following script: #!/bin/bash sleep 1000 & exec perf stat -a -e cycles -I1000 -- sleep 5 Since "perf stat" is launched by exec, the "sleep 1000" would be the child process of "perf stat". The wait4() call will not return because it's waiting for the child process "sleep 1000" to end. So 'perf stat' doesn't return even after 5s passes. This patch lets 'perf stat' return when the specified child process ends (in this case, the specified child process is "sleep 5"). Committer testing: # cat test.sh #!/bin/bash sleep 10 & exec perf stat -a -e cycles -I1000 -- sleep 5 # Before: # time ./test.sh # time counts unit events 1.001113090 108,453,351 cycles 2.002062196 142,075,435 cycles 3.002896194 164,801,068 cycles 4.003731666 107,062,140 cycles 5.002068867 112,241,832 cycles real 0m10.066s user 0m0.016s sys 0m0.101s # After: # time ./test.sh # time counts unit events 1.001016096 91,412,027 cycles 2.002014963 124,063,708 cycles 3.002883964 125,993,929 cycles 4.003706470 120,465,734 cycles 5.002006778 163,560,355 cycles real 0m5.123s user 0m0.014s sys 0m0.105s # Signed-off-by: Jin Yao Reviewed-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: Alexander Shishkin Cc: Andi Kleen Cc: Kan Liang Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1546501245-4512-1-git-send-email-yao.jin@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin --- tools/perf/builtin-stat.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c index 1410d66192f7..63a3afc7f32b 100644 --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -561,7 +561,8 @@ static int __run_perf_stat(int argc, const char **argv, int run_idx) break; } } - wait4(child_pid, &status, 0, &stat_config.ru_data); + if (child_pid != -1) + wait4(child_pid, &status, 0, &stat_config.ru_data); if (workload_exec_errno) { const char *emsg = str_error_r(workload_exec_errno, msg, sizeof(msg)); -- 2.19.1