From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752191Ab3HUPiR (ORCPT ); Wed, 21 Aug 2013 11:38:17 -0400 Received: from mga02.intel.com ([134.134.136.20]:2810 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751648Ab3HUPiQ (ORCPT ); Wed, 21 Aug 2013 11:38:16 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.89,928,1367996400"; d="scan'208";a="390991157" From: "Kirill A. Shutemov" To: Andrew Morton Cc: Dave Hansen , Jan Kara , Al Viro , NeilBrown , linux-mm@kvack.org, linux-kernel@vger.kernel.org, "Kirill A. Shutemov" Subject: [PATCH] mm, fs: avoid page allocation beyond i_size on read Date: Wed, 21 Aug 2013 18:37:21 +0300 Message-Id: <1377099441-2224-1-git-send-email-kirill.shutemov@linux.intel.com> X-Mailer: git-send-email 1.8.4.rc2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I've noticed that we allocated unneeded page for cache on read beyond i_size. Simple test case (I checked it on ramfs): $ touch testfile $ cat testfile It triggers 'no_cached_page' code path in do_generic_file_read(). Looks like it's regression since commit a32ea1e. Let's fix it. Signed-off-by: Kirill A. Shutemov Acked-by: NeilBrown --- mm/filemap.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/mm/filemap.c b/mm/filemap.c index 1905f0e..b1a4d35 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1163,6 +1163,10 @@ static void do_generic_file_read(struct file *filp, loff_t *ppos, loff_t isize; unsigned long nr, ret; + isize = i_size_read(inode); + if (!isize || index > (isize - 1) >> PAGE_CACHE_SHIFT) + goto out; + cond_resched(); find_page: page = find_get_page(mapping, index); -- 1.8.4.rc2