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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5D56BC433FE for ; Mon, 3 Jan 2022 21:33:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230059AbiACVds (ORCPT ); Mon, 3 Jan 2022 16:33:48 -0500 Received: from out03.mta.xmission.com ([166.70.13.233]:45860 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229996AbiACVdm (ORCPT ); Mon, 3 Jan 2022 16:33:42 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]:56344) by out03.mta.xmission.com with esmtps (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1n4UxY-00ET0Q-W5; Mon, 03 Jan 2022 14:33:41 -0700 Received: from ip68-110-24-146.om.om.cox.net ([68.110.24.146]:54408 helo=localhost.localdomain) by in02.mta.xmission.com with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.93) (envelope-from ) id 1n4UxX-006zvm-MV; Mon, 03 Jan 2022 14:33:40 -0700 From: "Eric W. Biederman" To: linux-kernel@vger.kernel.org Cc: linux-arch@vger.kernel.org, Linus Torvalds , Oleg Nesterov , Al Viro , Kees Cook , linux-api@vger.kernel.org, "Eric W. Biederman" , Balbir Singh Date: Mon, 3 Jan 2022 15:33:00 -0600 Message-Id: <20220103213312.9144-5-ebiederm@xmission.com> X-Mailer: git-send-email 2.20.1 In-Reply-To: <87r19opkx1.fsf_-_@email.froward.int.ebiederm.org> References: <87r19opkx1.fsf_-_@email.froward.int.ebiederm.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-XM-SPF: eid=1n4UxX-006zvm-MV;;;mid=<20220103213312.9144-5-ebiederm@xmission.com>;;;hst=in02.mta.xmission.com;;;ip=68.110.24.146;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1+CRWzVLNnenVGaaRiHLlq9SOWL8zsSG+U= X-SA-Exim-Connect-IP: 68.110.24.146 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH 05/17] taskstats: Cleanup the use of task->exit_code X-SA-Exim-Version: 4.2.1 (built Sat, 08 Feb 2020 21:53:50 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org 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") Signed-off-by: "Eric W. Biederman" --- kernel/tsacct.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/kernel/tsacct.c b/kernel/tsacct.c index f00de83d0246..1d261fbe367b 100644 --- a/kernel/tsacct.c +++ b/kernel/tsacct.c @@ -38,11 +38,10 @@ void bacct_add_tsk(struct user_namespace *user_ns, stats->ac_btime = clamp_t(time64_t, btime, 0, U32_MAX); stats->ac_btime64 = btime; - 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) -- 2.29.2