From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id CA1E26FBB for ; Tue, 10 Jan 2023 18:28:35 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 44CF8C433D2; Tue, 10 Jan 2023 18:28:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1673375315; bh=klK8k98N1/aMAR8o70ZfvSD3KevfMpw7nLCKsWQzM/8=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IUQymJ2HoGqf+bcgQ9kqKzwK5XM0vzvCHpvCSLAfypUuj+W4sSDLWOmLOouQdWwwc fU95ZwIE5a3UcNRIw9f/9ZGd+ogsEKbOoqhuIvaqfiAcoAgAuISKfEJtb2a8K2ZpLH etC1w86sBJVxVgbVu4ZjuevL5KvCAEOb1BM3h+HU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Jan Kara , Zhang Yi , Theodore Tso , stable@kernel.org Subject: [PATCH 5.15 149/290] ext4: check and assert if marking an no_delete evicting inode dirty Date: Tue, 10 Jan 2023 19:04:01 +0100 Message-Id: <20230110180036.980717866@linuxfoundation.org> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230110180031.620810905@linuxfoundation.org> References: <20230110180031.620810905@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Zhang Yi commit 318cdc822c63b6e2befcfdc2088378ae6fa18def upstream. In ext4_evict_inode(), if we evicting an inode in the 'no_delete' path, it cannot be raced by another mark_inode_dirty(). If it happens, someone else may accidentally dirty it without holding inode refcount and probably cause use-after-free issues in the writeback procedure. It's indiscoverable and hard to debug, so add an WARN_ON_ONCE() to check and detect this issue in advance. Suggested-by: Jan Kara Signed-off-by: Zhang Yi Reviewed-by: Jan Kara Link: https://lore.kernel.org/r/20220629112647.4141034-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman --- fs/ext4/inode.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -338,6 +338,12 @@ stop_handle: ext4_xattr_inode_array_free(ea_inode_array); return; no_delete: + /* + * Check out some where else accidentally dirty the evicting inode, + * which may probably cause inode use-after-free issues later. + */ + WARN_ON_ONCE(!list_empty_careful(&inode->i_io_list)); + if (!list_empty(&EXT4_I(inode)->i_fc_list)) ext4_fc_mark_ineligible(inode->i_sb, EXT4_FC_REASON_NOMEM, NULL); ext4_clear_inode(inode); /* We must guarantee clearing of inode... */