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=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS 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 EF3CDC43219 for ; Mon, 29 Apr 2019 16:32:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id BEF9320675 for ; Mon, 29 Apr 2019 16:32:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728629AbfD2Qcv (ORCPT ); Mon, 29 Apr 2019 12:32:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:41606 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728524AbfD2Qcv (ORCPT ); Mon, 29 Apr 2019 12:32:51 -0400 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id E995887623; Mon, 29 Apr 2019 16:32:50 +0000 (UTC) Received: from max.home.com (unknown [10.40.205.80]) by smtp.corp.redhat.com (Postfix) with ESMTP id 17BCD17A64; Mon, 29 Apr 2019 16:32:46 +0000 (UTC) From: Andreas Gruenbacher To: cluster-devel@redhat.com, Christoph Hellwig Cc: Bob Peterson , Jan Kara , Dave Chinner , Ross Lagerwall , Mark Syms , =?UTF-8?q?Edwin=20T=C3=B6r=C3=B6k?= , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, Andreas Gruenbacher Subject: [PATCH v6 2/4] iomap: Fix use-after-free error in page_done callback Date: Mon, 29 Apr 2019 18:32:37 +0200 Message-Id: <20190429163239.4874-2-agruenba@redhat.com> In-Reply-To: <20190429163239.4874-1-agruenba@redhat.com> References: <20190429163239.4874-1-agruenba@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.26]); Mon, 29 Apr 2019 16:32:51 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org In iomap_write_end, we're not holding a page reference anymore when calling the page_done callback, but the callback needs that reference to access the page. To fix that, move the put_page call in __generic_write_end into the callers of __generic_write_end. Then, in iomap_write_end, put the page after calling the page_done callback. Reported-by: Jan Kara Fixes: 63899c6f8851 ("iomap: add a page_done callback") Signed-off-by: Andreas Gruenbacher Reviewed-by: Jan Kara --- fs/buffer.c | 5 +++-- fs/iomap.c | 1 + 2 files changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/buffer.c b/fs/buffer.c index ce357602f471..6e2c95160ce3 100644 --- a/fs/buffer.c +++ b/fs/buffer.c @@ -2104,7 +2104,6 @@ int __generic_write_end(struct inode *inode, loff_t pos, unsigned copied, } unlock_page(page); - put_page(page); if (old_size < pos) pagecache_isize_extended(inode, old_size, pos); @@ -2160,7 +2159,9 @@ int generic_write_end(struct file *file, struct address_space *mapping, struct page *page, void *fsdata) { copied = block_write_end(file, mapping, pos, len, copied, page, fsdata); - return __generic_write_end(mapping->host, pos, copied, page); + copied = __generic_write_end(mapping->host, pos, copied, page); + put_page(page); + return copied; } EXPORT_SYMBOL(generic_write_end); diff --git a/fs/iomap.c b/fs/iomap.c index 2344c662e6fc..b01ed5a28d2c 100644 --- a/fs/iomap.c +++ b/fs/iomap.c @@ -780,6 +780,7 @@ iomap_write_end(struct inode *inode, loff_t pos, unsigned len, ret = __generic_write_end(inode, pos, ret, page); if (iomap->page_done) iomap->page_done(inode, pos, copied, page, iomap); + put_page(page); if (ret < len) iomap_write_failed(inode, pos, len); -- 2.20.1