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=-6.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,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 465B7C433FF for ; Thu, 8 Aug 2019 19:09:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1BF3E2173E for ; Thu, 8 Aug 2019 19:09:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565291395; bh=NImqE0H43sXb6ouffQcKmdoWHv9do+cIG5A2IeP2Eu4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=BYm8XvAeR2fFacdVDAxPSrobH8MKH4P2SJ6zRT0KgHG2Hg6ZvKoiivIEQM/MezNWE gO4mCV8OB2Hy+x21oaZyRd6m8/swfJAsh1OYMJLVDhBqL6buotXQnMEjYA9tGriw5A 8daiYR2jWyWzNEV1llPIX+lU3NvLRvyOwAfDFCWE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405188AbfHHTJx (ORCPT ); Thu, 8 Aug 2019 15:09:53 -0400 Received: from mail.kernel.org ([198.145.29.99]:44140 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405171AbfHHTJs (ORCPT ); Thu, 8 Aug 2019 15:09:48 -0400 Received: from localhost (83-86-89-107.cable.dynamic.v4.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 977A521743; Thu, 8 Aug 2019 19:09:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565291388; bh=NImqE0H43sXb6ouffQcKmdoWHv9do+cIG5A2IeP2Eu4=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=QRfNW0V/S0JbQg7WmD1JmE0F8oV/1tvcByP5RAne3P8MM9h9SSeLHEqK/7XnIOFxn YdtGK3GC5iz2tjMklHj2HUJIOI9G6MOdpWjzVz7arLxMV7WSMVZm4TfD8ToROzI7hN 5adwrWF42+/KCFpd+Be/Y0mD2t2YFnabTgdgzOUo= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tejun Heo , Oleg Nesterov Subject: [PATCH 4.19 40/45] cgroup: Call cgroup_release() before __exit_signal() Date: Thu, 8 Aug 2019 21:05:26 +0200 Message-Id: <20190808190456.128759505@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190808190453.827571908@linuxfoundation.org> References: <20190808190453.827571908@linuxfoundation.org> User-Agent: quilt/0.66 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 From: Tejun Heo commit 6b115bf58e6f013ca75e7115aabcbd56c20ff31d upstream. cgroup_release() calls cgroup_subsys->release() which is used by the pids controller to uncharge its pid. We want to use it to manage iteration of dying tasks which requires putting it before __unhash_process(). Move cgroup_release() above __exit_signal(). While this makes it uncharge before the pid is freed, pid is RCU freed anyway and the window is very narrow. Signed-off-by: Tejun Heo Cc: Oleg Nesterov Signed-off-by: Greg Kroah-Hartman --- kernel/exit.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/exit.c +++ b/kernel/exit.c @@ -194,6 +194,7 @@ repeat: rcu_read_unlock(); proc_flush_task(p); + cgroup_release(p); write_lock_irq(&tasklist_lock); ptrace_release_task(p); @@ -219,7 +220,6 @@ repeat: } write_unlock_irq(&tasklist_lock); - cgroup_release(p); release_thread(p); call_rcu(&p->rcu, delayed_put_task_struct);