From mboxrd@z Thu Jan 1 00:00:00 1970 From: npiggin@suse.de Subject: [patch 4/8] mm: write_cache_pages type overflow fix Date: Fri, 10 Oct 2008 02:50:43 +1100 Message-ID: <20081009174822.516911376@suse.de> References: <20081009155039.139856823@suse.de> Cc: Mikulas Patocka , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org To: Andrew Morton Return-path: Received: from cantor.suse.de ([195.135.220.2]:46825 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754868AbYJIH6m (ORCPT ); Thu, 9 Oct 2008 03:58:42 -0400 Content-Disposition: inline; filename=mm-wcp-type-overflow-fix.patch Sender: linux-fsdevel-owner@vger.kernel.org List-ID: In the range_cont case, range_start is set to index << PAGE_CACHE_SHIFT, but index is a pgoff_t and range_start is loff_t, so we can get truncation of the value on 32-bit platforms. Fix this by adding the standard loff_t cast. This is a data interity bug (depending on how range_cont is used). Signed-off-by: Nick Piggin --- Index: linux-2.6/mm/page-writeback.c =================================================================== --- linux-2.6.orig/mm/page-writeback.c +++ linux-2.6/mm/page-writeback.c @@ -976,7 +976,7 @@ again: mapping->writeback_index = index; if (wbc->range_cont) - wbc->range_start = index << PAGE_CACHE_SHIFT; + wbc->range_start = (loff_t)index << PAGE_CACHE_SHIFT; return ret; } EXPORT_SYMBOL(write_cache_pages); --