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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 56858C54FCB for ; Fri, 24 Apr 2020 20:53:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2B45320857 for ; Fri, 24 Apr 2020 20:53:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726087AbgDXUxc (ORCPT ); Fri, 24 Apr 2020 16:53:32 -0400 Received: from out02.mta.xmission.com ([166.70.13.232]:39094 "EHLO out02.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725970AbgDXUxb (ORCPT ); Fri, 24 Apr 2020 16:53:31 -0400 Received: from in01.mta.xmission.com ([166.70.13.51]) by out02.mta.xmission.com with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1jS5KE-0001YR-MD; Fri, 24 Apr 2020 14:53:30 -0600 Received: from ip68-227-160-95.om.om.cox.net ([68.227.160.95] helo=x220.xmission.com) by in01.mta.xmission.com with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.87) (envelope-from ) id 1jS5KE-0007t9-0i; Fri, 24 Apr 2020 14:53:30 -0600 From: ebiederm@xmission.com (Eric W. Biederman) To: Oleg Nesterov Cc: LKML , Linux FS Devel , Alexey Dobriyan , Alexey Gladkov , Andrew Morton , Alexey Gladkov , Linus Torvalds References: <20200419141057.621356-1-gladkov.alexey@gmail.com> <87ftcv1nqe.fsf@x220.int.ebiederm.org> <87wo66vvnm.fsf_-_@x220.int.ebiederm.org> <20200424173927.GB26802@redhat.com> Date: Fri, 24 Apr 2020 15:50:20 -0500 In-Reply-To: <20200424173927.GB26802@redhat.com> (Oleg Nesterov's message of "Fri, 24 Apr 2020 19:39:28 +0200") Message-ID: <875zdopq0j.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=1jS5KE-0007t9-0i;;;mid=<875zdopq0j.fsf_-_@x220.int.ebiederm.org>;;;hst=in01.mta.xmission.com;;;ip=68.227.160.95;;;frm=ebiederm@xmission.com;;;spf=neutral X-XM-AID: U2FsdGVkX1/PjcqSz7yy9YnzAu0s9P2ZBtebHz3Fjs4= X-SA-Exim-Connect-IP: 68.227.160.95 X-SA-Exim-Mail-From: ebiederm@xmission.com Subject: [PATCH] proc: Put thread_pid in release_task not proc_flush_pid X-SA-Exim-Version: 4.2.1 (built Thu, 05 May 2016 13:38:54 -0600) X-SA-Exim-Scanned: Yes (on in01.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Oleg pointed out that in the unlikely event the kernel is compiled with CONFIG_PROC_FS unset that release_task will now leak the pid. Move the put_pid out of proc_flush_pid into release_task to fix this and to guarantee I don't make that mistake again. When possible it makes sense to keep get and put in the same function so it can easily been seen how they pair up. Fixes: 7bc3e6e55acf ("proc: Use a list of inodes to flush from proc") Reported-by: Oleg Nesterov Signed-off-by: "Eric W. Biederman" --- fs/proc/base.c | 1 - kernel/exit.c | 1 + 2 files changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/proc/base.c b/fs/proc/base.c index 6042b646ab27..42f43c7b9669 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -3274,7 +3274,6 @@ static const struct inode_operations proc_tgid_base_inode_operations = { void proc_flush_pid(struct pid *pid) { proc_invalidate_siblings_dcache(&pid->inodes, &pid->lock); - put_pid(pid); } static struct dentry *proc_pid_instantiate(struct dentry * dentry, diff --git a/kernel/exit.c b/kernel/exit.c index 389a88cb3081..ce2a75bc0ade 100644 --- a/kernel/exit.c +++ b/kernel/exit.c @@ -219,6 +219,7 @@ void release_task(struct task_struct *p) write_unlock_irq(&tasklist_lock); proc_flush_pid(thread_pid); + put_pid(thread_pid); release_thread(p); put_task_struct_rcu_user(p); -- 2.20.1