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=-7.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_PASS,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 B4D38C43387 for ; Fri, 28 Dec 2018 12:18:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 835A820675 for ; Fri, 28 Dec 2018 12:18:54 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545999534; bh=6A1eIaMLcC+fjnsk7HOlhpSObdQhNzw+DuN/68z5SJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=aqiK7bQX+18TqFtbIuXDGyVnqxdlwxRGELQ+Ab7NFD8+hM12HXZwj2tlw+epp39Yc +cDTbUY9NNiVBRcbHBxCeWIVgtVx/9KAnU+yGAAlciuK04kzCIi4C2ErHJG7sXUXis Y6NyoD5n8V97d9ZXtVlsmZGhWPOjKf80Zb0xc6Ys= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733172AbeL1MSr (ORCPT ); Fri, 28 Dec 2018 07:18:47 -0500 Received: from mail.kernel.org ([198.145.29.99]:36892 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733023AbeL1MRr (ORCPT ); Fri, 28 Dec 2018 07:17:47 -0500 Received: from localhost (5356596B.cm-6-7b.dynamic.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 9D103218F0; Fri, 28 Dec 2018 12:17:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1545999467; bh=6A1eIaMLcC+fjnsk7HOlhpSObdQhNzw+DuN/68z5SJg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uGRw/v/Mhxx0dY2PjJXdw4sxLaRgAjHfhMWrYJJGDuSqOs8Bvz3cMeuFrXI781Puv beDohgDShAygWqjGP9GnskE56SaU1GaafeDiyCWif9sVaDOGUtzDoTLnHOPtAp4yjf 69CxJy9pgl+YdNP/n++fVzxWbUK6XSHQ9I7bR/f8= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Ivan Delalande , Al Viro Subject: [PATCH 4.9 21/22] proc/sysctl: dont return ENOMEM on lookup when a table is unregistering Date: Fri, 28 Dec 2018 12:52:58 +0100 Message-Id: <20181228113127.624192129@linuxfoundation.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20181228113126.144310132@linuxfoundation.org> References: <20181228113126.144310132@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review X-Patchwork-Hint: ignore 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 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Ivan Delalande commit ea5751ccd665a2fd1b24f9af81f6167f0718c5f6 upstream. proc_sys_lookup can fail with ENOMEM instead of ENOENT when the corresponding sysctl table is being unregistered. In our case we see this upon opening /proc/sys/net/*/conf files while network interfaces are being deleted, which confuses our configuration daemon. The problem was successfully reproduced and this fix tested on v4.9.122 and v4.20-rc6. v2: return ERR_PTRs in all cases when proc_sys_make_inode fails instead of mixing them with NULL. Thanks Al Viro for the feedback. Fixes: ace0c791e6c3 ("proc/sysctl: Don't grab i_lock under sysctl_lock.") Cc: stable@vger.kernel.org Signed-off-by: Ivan Delalande Signed-off-by: Al Viro Signed-off-by: Greg Kroah-Hartman --- fs/proc/proc_sysctl.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) --- a/fs/proc/proc_sysctl.c +++ b/fs/proc/proc_sysctl.c @@ -466,7 +466,7 @@ static struct inode *proc_sys_make_inode inode = new_inode(sb); if (!inode) - goto out; + return ERR_PTR(-ENOMEM); inode->i_ino = get_next_ino(); @@ -476,8 +476,7 @@ static struct inode *proc_sys_make_inode if (unlikely(head->unregistering)) { spin_unlock(&sysctl_lock); iput(inode); - inode = NULL; - goto out; + return ERR_PTR(-ENOENT); } ei->sysctl = head; ei->sysctl_entry = table; @@ -502,7 +501,6 @@ static struct inode *proc_sys_make_inode if (root->set_ownership) root->set_ownership(head, table, &inode->i_uid, &inode->i_gid); -out: return inode; } @@ -551,10 +549,11 @@ static struct dentry *proc_sys_lookup(st goto out; } - err = ERR_PTR(-ENOMEM); inode = proc_sys_make_inode(dir->i_sb, h ? h : head, p); - if (!inode) + if (IS_ERR(inode)) { + err = ERR_CAST(inode); goto out; + } err = NULL; d_set_d_op(dentry, &proc_sys_dentry_operations); @@ -687,7 +686,7 @@ static bool proc_sys_fill_cache(struct f return false; if (d_in_lookup(child)) { inode = proc_sys_make_inode(dir->d_sb, head, table); - if (!inode) { + if (IS_ERR(inode)) { d_lookup_done(child); dput(child); return false;