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=-15.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 DA3E7C11F66 for ; Wed, 14 Jul 2021 17:07:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC03F613B9 for ; Wed, 14 Jul 2021 17:07:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236088AbhGNRKj (ORCPT ); Wed, 14 Jul 2021 13:10:39 -0400 Received: from mga06.intel.com ([134.134.136.31]:26414 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229591AbhGNRKi (ORCPT ); Wed, 14 Jul 2021 13:10:38 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10045"; a="271502514" X-IronPort-AV: E=Sophos;i="5.84,239,1620716400"; d="scan'208";a="271502514" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2021 10:07:46 -0700 X-IronPort-AV: E=Sophos;i="5.84,239,1620716400"; d="scan'208";a="571239941" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jul 2021 10:07:46 -0700 Date: Wed, 14 Jul 2021 10:07:46 -0700 From: Ira Weiny To: Javier Pello Cc: Jan Kara , Jan Kara , linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] fs/ext2: Avoid page_address on pages returned by ext2_get_page Message-ID: <20210714170746.GL3169279@iweiny-DESK2.sc.intel.com> References: <20210713165821.8a268e2c1db4fd5cf452acd2@urjc.es> <20210713165918.10da0318af5b9b73e599a517@urjc.es> <20210713163018.GF24271@quack2.suse.cz> <20210713193319.a223cd12e3fb8687f0cae0e8@urjc.es> <20210714090013.GA9457@quack2.suse.cz> <20210714185448.8707ac239e9f12b3a7f5b9f9@urjc.es> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210714185448.8707ac239e9f12b3a7f5b9f9@urjc.es> User-Agent: Mutt/1.11.1 (2018-12-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 14, 2021 at 06:54:48PM +0200, Javier Pello wrote: > From: Javier Pello > > Commit 782b76d7abdf02b12c46ed6f1e9bf715569027f7 ("fs/ext2: Replace > kmap() with kmap_local_page()") replaced the kmap/kunmap calls in > ext2_get_page/ext2_put_page with kmap_local_page/kunmap_local for > efficiency reasons. As a necessary side change, the commit also > made ext2_get_page (and ext2_find_entry and ext2_dotdot) return > the mapping address along with the page itself, as it is required > for kunmap_local, and converted uses of page_address on such pages > to use the newly returned address instead. However, uses of > page_address on such pages were missed in ext2_check_page and > ext2_delete_entry, which triggers oopses if kmap_local_page happens > to return an address from high memory. Fix this now by converting > the remaining uses of page_address to use the right address, as > returned by kmap_local_page. > Again thanks for catching this! Reviewed-by: Ira Weiny > Signed-off-by: Javier Pello > Fixes: 782b76d7abdf ("fs/ext2: Replace kmap() with kmap_local_page()") > --- > > v2: Use char * for the new parameter to ext2_delete_entry. > > fs/ext2/dir.c | 12 ++++++------ > fs/ext2/ext2.h | 3 ++- > fs/ext2/namei.c | 4 ++-- > 3 files changed, 10 insertions(+), 9 deletions(-) > > diff --git a/fs/ext2/dir.c b/fs/ext2/dir.c > index 14292dba..2c2f179b 100644 > --- a/fs/ext2/dir.c > +++ b/fs/ext2/dir.c > @@ -106,12 +106,11 @@ static int ext2_commit_chunk(struct page *page, loff_t pos, unsigned len) > return err; > } > > -static bool ext2_check_page(struct page *page, int quiet) > +static bool ext2_check_page(struct page *page, int quiet, char *kaddr) > { > struct inode *dir = page->mapping->host; > struct super_block *sb = dir->i_sb; > unsigned chunk_size = ext2_chunk_size(dir); > - char *kaddr = page_address(page); > u32 max_inumber = le32_to_cpu(EXT2_SB(sb)->s_es->s_inodes_count); > unsigned offs, rec_len; > unsigned limit = PAGE_SIZE; > @@ -205,7 +204,8 @@ static struct page * ext2_get_page(struct inode *dir, unsigned long n, > if (!IS_ERR(page)) { > *page_addr = kmap_local_page(page); > if (unlikely(!PageChecked(page))) { > - if (PageError(page) || !ext2_check_page(page, quiet)) > + if (PageError(page) || !ext2_check_page(page, quiet, > + *page_addr)) > goto fail; > } > } > @@ -584,10 +584,10 @@ int ext2_add_link (struct dentry *dentry, struct inode *inode) > * ext2_delete_entry deletes a directory entry by merging it with the > * previous entry. Page is up-to-date. > */ > -int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) > +int ext2_delete_entry (struct ext2_dir_entry_2 *dir, struct page *page, > + char *kaddr) > { > struct inode *inode = page->mapping->host; > - char *kaddr = page_address(page); > unsigned from = ((char*)dir - kaddr) & ~(ext2_chunk_size(inode)-1); > unsigned to = ((char *)dir - kaddr) + > ext2_rec_len_from_disk(dir->rec_len); > @@ -607,7 +607,7 @@ int ext2_delete_entry (struct ext2_dir_entry_2 * dir, struct page * page ) > de = ext2_next_entry(de); > } > if (pde) > - from = (char*)pde - (char*)page_address(page); > + from = (char *)pde - kaddr; > pos = page_offset(page) + from; > lock_page(page); > err = ext2_prepare_chunk(page, pos, to - from); > diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h > index b0a69482..e512630c 100644 > --- a/fs/ext2/ext2.h > +++ b/fs/ext2/ext2.h > @@ -740,7 +740,8 @@ extern int ext2_inode_by_name(struct inode *dir, > extern int ext2_make_empty(struct inode *, struct inode *); > extern struct ext2_dir_entry_2 *ext2_find_entry(struct inode *, const struct qstr *, > struct page **, void **res_page_addr); > -extern int ext2_delete_entry (struct ext2_dir_entry_2 *, struct page *); > +extern int ext2_delete_entry(struct ext2_dir_entry_2 *dir, struct page *page, > + char *kaddr); > extern int ext2_empty_dir (struct inode *); > extern struct ext2_dir_entry_2 *ext2_dotdot(struct inode *dir, struct page **p, void **pa); > extern void ext2_set_link(struct inode *, struct ext2_dir_entry_2 *, struct page *, void *, > diff --git a/fs/ext2/namei.c b/fs/ext2/namei.c > index 1f69b816..5f6b7560 100644 > --- a/fs/ext2/namei.c > +++ b/fs/ext2/namei.c > @@ -293,7 +293,7 @@ static int ext2_unlink(struct inode * dir, struct dentry *dentry) > goto out; > } > > - err = ext2_delete_entry (de, page); > + err = ext2_delete_entry (de, page, page_addr); > ext2_put_page(page, page_addr); > if (err) > goto out; > @@ -397,7 +397,7 @@ static int ext2_rename (struct user_namespace * mnt_userns, > old_inode->i_ctime = current_time(old_inode); > mark_inode_dirty(old_inode); > > - ext2_delete_entry(old_de, old_page); > + ext2_delete_entry(old_de, old_page, old_page_addr); > > if (dir_de) { > if (old_dir != new_dir) > -- > 2.30.1