From patchwork Thu Jan 7 07:53:12 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Wen Yang X-Patchwork-Id: 359735 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, UNPARSEABLE_RELAY, 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 EB4BDC433E0 for ; Thu, 7 Jan 2021 07:54:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A809323125 for ; Thu, 7 Jan 2021 07:54:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727418AbhAGHye (ORCPT ); Thu, 7 Jan 2021 02:54:34 -0500 Received: from out30-54.freemail.mail.aliyun.com ([115.124.30.54]:48027 "EHLO out30-54.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727396AbhAGHyE (ORCPT ); Thu, 7 Jan 2021 02:54:04 -0500 X-Alimail-AntiSpam: AC=PASS; BC=-1|-1; BR=01201311R161e4; CH=green; DM=||false|; DS=||; FP=0|-1|-1|-1|0|-1|-1|-1; HT=e01e04420; MF=wenyang@linux.alibaba.com; NM=1; PH=DS; RN=7; SR=0; TI=SMTPD_---0UKzNwIV_1610006000; Received: from localhost(mailfrom:wenyang@linux.alibaba.com fp:SMTPD_---0UKzNwIV_1610006000) by smtp.aliyun-inc.com(127.0.0.1); Thu, 07 Jan 2021 15:53:20 +0800 From: Wen Yang To: Greg Kroah-Hartman , Sasha Levin Cc: Xunlei Pang , linux-kernel@vger.kernel.org, "Eric W. Biederman" , stable@vger.kernel.org, Wen Yang Subject: [PATCH 4.19 5/7] proc: Clear the pieces of proc_inode that proc_evict_inode cares about Date: Thu, 7 Jan 2021 15:53:12 +0800 Message-Id: <20210107075314.62683-6-wenyang@linux.alibaba.com> X-Mailer: git-send-email 2.23.0 In-Reply-To: <20210107075314.62683-1-wenyang@linux.alibaba.com> References: <20210107075314.62683-1-wenyang@linux.alibaba.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: "Eric W. Biederman" [ Upstream commit 71448011ea2a1cd36d8f5cbdab0ed716c454d565 ] This just keeps everything tidier, and allows for using flags like SLAB_TYPESAFE_BY_RCU where slabs are not always cleared before reuse. I don't see reuse without reinitializing happening with the proc_inode but I had a false alarm while reworking flushing of proc dentries and indoes when a process dies that caused me to tidy this up. The code is a little easier to follow and reason about this way so I figured the changes might as well be kept. Signed-off-by: "Eric W. Biederman" Cc: # 4.19.x Signed-off-by: Wen Yang --- fs/proc/inode.c | 16 +++++++++++----- 1 file changed, 11 insertions(+), 5 deletions(-) diff --git a/fs/proc/inode.c b/fs/proc/inode.c index fffc7e4..45b4344 100644 --- a/fs/proc/inode.c +++ b/fs/proc/inode.c @@ -34,21 +34,27 @@ static void proc_evict_inode(struct inode *inode) { struct proc_dir_entry *de; struct ctl_table_header *head; + struct proc_inode *ei = PROC_I(inode); truncate_inode_pages_final(&inode->i_data); clear_inode(inode); /* Stop tracking associated processes */ - put_pid(PROC_I(inode)->pid); + if (ei->pid) { + put_pid(ei->pid); + ei->pid = NULL; + } /* Let go of any associated proc directory entry */ - de = PDE(inode); - if (de) + de = ei->pde; + if (de) { pde_put(de); + ei->pde = NULL; + } - head = PROC_I(inode)->sysctl; + head = ei->sysctl; if (head) { - RCU_INIT_POINTER(PROC_I(inode)->sysctl, NULL); + RCU_INIT_POINTER(ei->sysctl, NULL); proc_sys_evict_inode(inode, head); } }