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=unavailable 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 7A618C433FF for ; Thu, 8 Aug 2019 19:11:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 43BA821882 for ; Thu, 8 Aug 2019 19:11:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565291502; bh=aA4NlhqRdzaZLnxk3Me8hAUpVSOE5IDr/BhVKV2QNNI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aUX1srFnfsEjh8o5H9bkepxZ2N0pIseJn/hsvcf8nbNVRS3wX8Ey/W3tB9hyKhytH MgCYFoctqo+Csa6rAuMV21Aqwl856VmHWtU46ilX+wqCQAeqpuhI6geGIDQOVmG+It fGVvIqMCtkFPFFTvL/5lZ9anEeYgIqAY4OD38mTU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405527AbfHHTLk (ORCPT ); Thu, 8 Aug 2019 15:11:40 -0400 Received: from mail.kernel.org ([198.145.29.99]:46194 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2405511AbfHHTLe (ORCPT ); Thu, 8 Aug 2019 15:11:34 -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 812012184E; Thu, 8 Aug 2019 19:11:33 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1565291494; bh=aA4NlhqRdzaZLnxk3Me8hAUpVSOE5IDr/BhVKV2QNNI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=o02omHFrmEKFldU3VWj4Fi2HYELlK34ZGHOTBaDVXku4e2vtrf4yXlT8uWzW//1rn 07FRdCm6wLs6O8s8Ub7jFbql96P+vmg0ZAG5co8QHlrwtE3HKVPPplNua9gYNtO7hG P5bBBswcfoEgqgAi/SvDhvo4b/HYlNzLrSeLxzzQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Tejun Heo , Oleg Nesterov Subject: [PATCH 4.14 28/33] cgroup: Call cgroup_release() before __exit_signal() Date: Thu, 8 Aug 2019 21:05:35 +0200 Message-Id: <20190808190455.054993030@linuxfoundation.org> X-Mailer: git-send-email 2.22.0 In-Reply-To: <20190808190453.582417307@linuxfoundation.org> References: <20190808190453.582417307@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 @@ -193,6 +193,7 @@ repeat: rcu_read_unlock(); proc_flush_task(p); + cgroup_release(p); write_lock_irq(&tasklist_lock); ptrace_release_task(p); @@ -218,7 +219,6 @@ repeat: } write_unlock_irq(&tasklist_lock); - cgroup_release(p); release_thread(p); call_rcu(&p->rcu, delayed_put_task_struct);