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=-6.7 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 40E61C3F2CD for ; Wed, 4 Mar 2020 05:23:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1E10920842 for ; Wed, 4 Mar 2020 05:23:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726143AbgCDFXf (ORCPT ); Wed, 4 Mar 2020 00:23:35 -0500 Received: from out03.mta.xmission.com ([166.70.13.233]:59444 "EHLO out03.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725774AbgCDFXe (ORCPT ); Wed, 4 Mar 2020 00:23:34 -0500 Received: from in02.mta.xmission.com ([166.70.13.52]) by out03.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1j9MVJ-00082y-7k; Tue, 03 Mar 2020 22:23:33 -0700 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in02.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1j9MV6-0003OP-Vb; Tue, 03 Mar 2020 22:23:33 -0700 From: ebiederm@xmission.com (Eric W. Biederman) To: Qian Cai Cc: tglx@linutronix.de, oleg@redhat.com, linux-kernel@vger.kernel.org References: <20200304004336.960-1-cai@lca.pw> Date: Tue, 03 Mar 2020 23:21:11 -0600 In-Reply-To: <20200304004336.960-1-cai@lca.pw> (Qian Cai's message of "Tue, 3 Mar 2020 19:43:36 -0500") Message-ID: <877e00hf08.fsf@x220.int.ebiederm.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-SPF: eid=1j9MV6-0003OP-Vb;;;mid=<877e00hf08.fsf@x220.int.ebiederm.org>;;;hst=in02.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX18+dbHGiv/ztm3INrbnp2Mweg4CvI0F3KI= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH timers/core] posix-cpu-timers: Put the task_struct in posix_cpu_timers_create X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Qian Cai writes: > The recent commit removed put_task_struct() in posix_cpu_timer_del() > results in many memory leaks like this, > > unreferenced object 0xc0000016d9b44480 (size 8192): > comm "timer_create01", pid 57749, jiffies 4295163733 (age 6159.670s) > hex dump (first 32 bytes): > 02 00 00 00 00 00 00 00 10 00 00 00 00 00 00 00 ................ > 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ > backtrace: > [<0000000056aca129>] copy_process+0x26c/0x18e0 > alloc_task_struct_node at kernel/fork.c:169 > (inlined by) dup_task_struct at kernel/fork.c:877 > (inlined by) copy_process at kernel/fork.c:1929 > [<00000000bdbbf9f8>] _do_fork+0xac/0xb20 > [<00000000dcb1c445>] __do_sys_clone+0x98/0xe0 > __do_sys_clone at kernel/fork.c:2591 > [<000000006c059205>] ppc_clone+0x8/0xc > ppc_clone at arch/powerpc/kernel/entry_64.S:479 > I forgot that get_task_for_clock called by posix_cpu_timer_create returns a reference to a task_struct. Put that reference to avoid the leak. Link: https://lore.kernel.org/lkml/20200304004336.960-1-cai@lca.pw/ Fixes: 672ebe8eb017a5 ("posix-cpu-timers: Store a reference to a pid not a task") Reported-by: Qian Cai Signed-off-by: "Eric W. Biederman" --- kernel/time/posix-cpu-timers.c | 1 + 1 file changed, 1 insertion(+) diff --git a/kernel/time/posix-cpu-timers.c b/kernel/time/posix-cpu-timers.c index 1c21f2fd3d9b..cd88c1217224 100644 --- a/kernel/time/posix-cpu-timers.c +++ b/kernel/time/posix-cpu-timers.c @@ -405,6 +405,7 @@ static int posix_cpu_timer_create(struct k_itimer *new_timer) new_timer->kclock = &clock_posix_cpu; timerqueue_init(&new_timer->it.cpu.node); new_timer->it.cpu.pid = get_task_pid(p, cpu_timer_pid_type(new_timer)); + put_task_struct(p); return 0; } -- 2.20.1