Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161209AbXAMDZn (ORCPT ); Fri, 12 Jan 2007 22:25:43 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1161227AbXAMDZj (ORCPT ); Fri, 12 Jan 2007 22:25:39 -0500 Received: from cantor.suse.de ([195.135.220.2]:49574 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161209AbXAMDZF (ORCPT ); Fri, 12 Jan 2007 22:25:05 -0500 From: Nick Piggin To: Linux Memory Management Cc: Linux Kernel , Linux Filesystems , Nick Piggin , Andrew Morton Message-Id: <20070113011246.9449.54835.sendpatchset@linux.site> In-Reply-To: <20070113011159.9449.4327.sendpatchset@linux.site> References: <20070113011159.9449.4327.sendpatchset@linux.site> Subject: [patch 5/10] mm: debug write deadlocks Date: Sat, 13 Jan 2007 04:25:02 +0100 (CET) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1212 Lines: 34 Allow CONFIG_DEBUG_VM to switch off the prefaulting logic, to simulate the difficult race where the page may be unmapped before calling copy_from_user. Makes the race much easier to hit. This is useful for demonstration and testing purposes, but is removed in a subsequent patch. Signed-off-by: Nick Piggin Index: linux-2.6/mm/filemap.c =================================================================== --- linux-2.6.orig/mm/filemap.c +++ linux-2.6/mm/filemap.c @@ -1894,6 +1894,7 @@ generic_file_buffered_write(struct kiocb if (maxlen > bytes) maxlen = bytes; +#ifndef CONFIG_DEBUG_VM /* * Bring in the user page that we will copy from _first_. * Otherwise there's a nasty deadlock on copying from the @@ -1901,6 +1902,7 @@ generic_file_buffered_write(struct kiocb * up-to-date. */ fault_in_pages_readable(buf, maxlen); +#endif page = __grab_cache_page(mapping,index,&cached_page,&lru_pvec); if (!page) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/