From patchwork Mon Feb 21 08:49:12 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Greg KH X-Patchwork-Id: 544955 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id CB9FAC433FE for ; Mon, 21 Feb 2022 09:05:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347013AbiBUJFg (ORCPT ); Mon, 21 Feb 2022 04:05:36 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:41962 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347131AbiBUJEn (ORCPT ); Mon, 21 Feb 2022 04:04:43 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [IPv6:2604:1380:4601:e00::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F38562DD5E; Mon, 21 Feb 2022 00:58:49 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 8C51FB80EB7; Mon, 21 Feb 2022 08:58:48 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id AAF88C340E9; Mon, 21 Feb 2022 08:58:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1645433927; bh=h5Dw3Vgeme5qSV/8KduGsJ/MLiraukhAcg98o51JmQY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=ZT5aGzS7OuGWa3KWyJufRYnN6jcbTApp2O+mvXHkbj7VKYyaYc/empae3KJebqbik cSvKFGLRKacMYLvh/QNCLe2HDfMMVkyxgcqh+BXeCn+uBIIbA0beLfq76a3RCxP1a9 BLEst0XxgrULgDlJyASlpVOJjfTqUd6ZyBnRtfrU= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Balbir Singh , "Eric W. Biederman" , Sudip Mukherjee Subject: [PATCH 5.4 32/80] taskstats: Cleanup the use of task->exit_code Date: Mon, 21 Feb 2022 09:49:12 +0100 Message-Id: <20220221084916.628257481@linuxfoundation.org> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221084915.554151737@linuxfoundation.org> References: <20220221084915.554151737@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Eric W. Biederman" commit 1b5a42d9c85f0e731f01c8d1129001fd8531a8a0 upstream. In the function bacct_add_task the code reading task->exit_code was introduced in commit f3cef7a99469 ("[PATCH] csa: basic accounting over taskstats"), and it is not entirely clear what the taskstats interface is trying to return as only returning the exit_code of the first task in a process doesn't make a lot of sense. As best as I can figure the intent is to return task->exit_code after a task exits. The field is returned with per task fields, so the exit_code of the entire process is not wanted. Only the value of the first task is returned so this is not a useful way to get the per task ptrace stop code. The ordinary case of returning this value is returning after a task exits, which also precludes use for getting a ptrace value. It is common to for the first task of a process to also be the last task of a process so this field may have done something reasonable by accident in testing. Make ac_exitcode a reliable per task value by always returning it for every exited task. Setting ac_exitcode in a sensible mannter makes it possible to continue to provide this value going forward. Cc: Balbir Singh Fixes: f3cef7a99469 ("[PATCH] csa: basic accounting over taskstats") Link: https://lkml.kernel.org/r/20220103213312.9144-5-ebiederm@xmission.com Signed-off-by: "Eric W. Biederman" [sudip: adjust context] Signed-off-by: Sudip Mukherjee Signed-off-by: Greg Kroah-Hartman --- kernel/tsacct.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -35,11 +35,10 @@ void bacct_add_tsk(struct user_namespace /* Convert to seconds for btime */ do_div(delta, USEC_PER_SEC); stats->ac_btime = get_seconds() - delta; - if (thread_group_leader(tsk)) { + if (tsk->flags & PF_EXITING) stats->ac_exitcode = tsk->exit_code; - if (tsk->flags & PF_FORKNOEXEC) - stats->ac_flag |= AFORK; - } + if (thread_group_leader(tsk) && (tsk->flags & PF_FORKNOEXEC)) + stats->ac_flag |= AFORK; if (tsk->flags & PF_SUPERPRIV) stats->ac_flag |= ASU; if (tsk->flags & PF_DUMPCORE)