From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1162418Ab2GLWrS (ORCPT ); Thu, 12 Jul 2012 18:47:18 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:61447 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1162396Ab2GLWqU (ORCPT ); Thu, 12 Jul 2012 18:46:20 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: Greg KH , torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Bob Liu , Hugh Dickins , David Howells , Geert Uytterhoeven , Greg Ungerer Subject: [ 185/187] fs: ramfs: file-nommu: add SetPageUptodate() Date: Thu, 12 Jul 2012 15:35:41 -0700 Message-Id: <20120712191540.437913535@linuxfoundation.org> X-Mailer: git-send-email 1.7.10.1.362.g242cab3 In-Reply-To: <20120712191522.742634173@linuxfoundation.org> References: <20120712192421.GA28926@kroah.com> <20120712191522.742634173@linuxfoundation.org> User-Agent: quilt/0.60-20.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Greg KH 3.4-stable review patch. If anyone has any objections, please let me know. ------------------ From: Bob Liu commit fea9f718b3d68147f162ed2d870183ce5e0ad8d8 upstream. There is a bug in the below scenario for !CONFIG_MMU: 1. create a new file 2. mmap the file and write to it 3. read the file can't get the correct value Because sys_read() -> generic_file_aio_read() -> simple_readpage() -> clear_page() which causes the page to be zeroed. Add SetPageUptodate() to ramfs_nommu_expand_for_mapping() so that generic_file_aio_read() do not call simple_readpage(). Signed-off-by: Bob Liu Cc: Hugh Dickins Cc: David Howells Cc: Geert Uytterhoeven Cc: Greg Ungerer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- fs/ramfs/file-nommu.c | 1 + 1 file changed, 1 insertion(+) --- a/fs/ramfs/file-nommu.c +++ b/fs/ramfs/file-nommu.c @@ -110,6 +110,7 @@ int ramfs_nommu_expand_for_mapping(struc /* prevent the page from being discarded on memory pressure */ SetPageDirty(page); + SetPageUptodate(page); unlock_page(page); put_page(page);