From patchwork Fri Apr 24 20:50:20 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Eric W. Biederman" X-Patchwork-Id: 11509385 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id E656D92A for ; Fri, 24 Apr 2020 20:53:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D55A421556 for ; Fri, 24 Apr 2020 20:53:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726046AbgDXUxc (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 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 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on sa07.xmission.com X-Spam-Level: X-Spam-Status: No, score=0.5 required=8.0 tests=ALL_TRUSTED,BAYES_50, DCC_CHECK_NEGATIVE,T_TM2_M_HEADER_IN_MSG,XMSubLong autolearn=disabled version=3.4.2 X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.8 BAYES_50 BODY: Bayes spam probability is 40 to 60% * [score: 0.4999] * 0.7 XMSubLong Long Subject * 0.0 T_TM2_M_HEADER_IN_MSG BODY: No description available. * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Oleg Nesterov X-Spam-Relay-Country: X-Spam-Timing: total 277 ms - load_scoreonly_sql: 0.04 (0.0%), signal_user_changed: 11 (4.1%), b_tie_ro: 10 (3.5%), parse: 0.83 (0.3%), extract_message_metadata: 11 (3.9%), get_uri_detail_list: 1.13 (0.4%), tests_pri_-1000: 13 (4.8%), tests_pri_-950: 1.23 (0.4%), tests_pri_-900: 1.07 (0.4%), tests_pri_-90: 59 (21.2%), check_bayes: 57 (20.7%), b_tokenize: 6 (2.2%), b_tok_get_all: 6 (2.0%), b_comp_prob: 1.88 (0.7%), b_tok_touch_all: 41 (14.7%), b_finish: 0.80 (0.3%), tests_pri_0: 168 (60.7%), check_dkim_signature: 0.53 (0.2%), check_dkim_adsp: 2.2 (0.8%), poll_dns_idle: 0.56 (0.2%), tests_pri_10: 2.2 (0.8%), tests_pri_500: 7 (2.5%), rewrite_mail: 0.00 (0.0%) Subject: [PATCH] proc: Put thread_pid in release_task not proc_flush_pid X-Spam-Flag: No 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-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@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);