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,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 ED64AC352A3 for ; Mon, 10 Feb 2020 12:36:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C735321739 for ; Mon, 10 Feb 2020 12:36:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338183; bh=BkvKZEpM8CH28dLrqyqUSwo4kAnmN+nebLwth9EK3sc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=W5ZIMuz8UOosvkJr4XmoicIm+myUPiV/2dYjPl5tvJ1jAAmBaLQEp39P48a16kEG1 H4f/j2k9UBUiBAI7s/LKUOIH2VDsFZ4geHjzb0ZYUMZLcYhYOMbxkZ6qiYUceP8T+V WY4ND1nophTeBn0EvnEbt0cwuKv3giUrBy4I2bqI= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728359AbgBJMgX (ORCPT ); Mon, 10 Feb 2020 07:36:23 -0500 Received: from mail.kernel.org ([198.145.29.99]:52932 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728107AbgBJMfq (ORCPT ); Mon, 10 Feb 2020 07:35:46 -0500 Received: from localhost (unknown [209.37.97.194]) (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 A12E4208C4; Mon, 10 Feb 2020 12:35:45 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1581338145; bh=BkvKZEpM8CH28dLrqyqUSwo4kAnmN+nebLwth9EK3sc=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=dLPWVJUW0ac7O6dI3z+P9tNlcjgory4V8WKSQJGzB+ss2EHcqosRR9JzgHeqOcQYD oNatasR2Tu17ROpv1aFFmBuW9ygq5fluxfdUywcK5UD4c4x0DfX++VB9lfcva/kLXM vaTixQV1RPfeJCZZcvkuKbK7qmCCh6mybv3NwKnQ= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Trond Myklebust , Benjamin Coddington , Anna Schumaker Subject: [PATCH 4.19 104/195] NFS: Directory page cache pages need to be locked when read Date: Mon, 10 Feb 2020 04:32:42 -0800 Message-Id: <20200210122315.501811833@linuxfoundation.org> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200210122305.731206734@linuxfoundation.org> References: <20200210122305.731206734@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: Trond Myklebust commit 114de38225d9b300f027e2aec9afbb6e0def154b upstream. When a NFS directory page cache page is removed from the page cache, its contents are freed through a call to nfs_readdir_clear_array(). To prevent the removal of the page cache entry until after we've finished reading it, we must take the page lock. Fixes: 11de3b11e08c ("NFS: Fix a memory leak in nfs_readdir") Cc: stable@vger.kernel.org # v2.6.37+ Signed-off-by: Trond Myklebust Reviewed-by: Benjamin Coddington Signed-off-by: Anna Schumaker Signed-off-by: Greg Kroah-Hartman --- fs/nfs/dir.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-) --- a/fs/nfs/dir.c +++ b/fs/nfs/dir.c @@ -701,8 +701,6 @@ int nfs_readdir_filler(nfs_readdir_descr static void cache_page_release(nfs_readdir_descriptor_t *desc) { - if (!desc->page->mapping) - nfs_readdir_clear_array(desc->page); put_page(desc->page); desc->page = NULL; } @@ -716,19 +714,28 @@ struct page *get_cache_page(nfs_readdir_ /* * Returns 0 if desc->dir_cookie was found on page desc->page_index + * and locks the page to prevent removal from the page cache. */ static -int find_cache_page(nfs_readdir_descriptor_t *desc) +int find_and_lock_cache_page(nfs_readdir_descriptor_t *desc) { int res; desc->page = get_cache_page(desc); if (IS_ERR(desc->page)) return PTR_ERR(desc->page); - - res = nfs_readdir_search_array(desc); + res = lock_page_killable(desc->page); if (res != 0) - cache_page_release(desc); + goto error; + res = -EAGAIN; + if (desc->page->mapping != NULL) { + res = nfs_readdir_search_array(desc); + if (res == 0) + return 0; + } + unlock_page(desc->page); +error: + cache_page_release(desc); return res; } @@ -743,7 +750,7 @@ int readdir_search_pagecache(nfs_readdir desc->last_cookie = 0; } do { - res = find_cache_page(desc); + res = find_and_lock_cache_page(desc); } while (res == -EAGAIN); return res; } @@ -782,7 +789,6 @@ int nfs_do_filldir(nfs_readdir_descripto desc->eof = true; kunmap(desc->page); - cache_page_release(desc); dfprintk(DIRCACHE, "NFS: nfs_do_filldir() filling ended @ cookie %Lu; returning = %d\n", (unsigned long long)*desc->dir_cookie, res); return res; @@ -828,13 +834,13 @@ int uncached_readdir(nfs_readdir_descrip status = nfs_do_filldir(desc); + out_release: + nfs_readdir_clear_array(desc->page); + cache_page_release(desc); out: dfprintk(DIRCACHE, "NFS: %s: returns %d\n", __func__, status); return status; - out_release: - cache_page_release(desc); - goto out; } /* The file offset position represents the dirent entry number. A @@ -899,6 +905,8 @@ static int nfs_readdir(struct file *file break; res = nfs_do_filldir(desc); + unlock_page(desc->page); + cache_page_release(desc); if (res < 0) break; } while (!desc->eof);