From mboxrd@z Thu Jan 1 00:00:00 1970 From: Nick Piggin Message-Id: <20061013143606.15438.18462.sendpatchset@linux.site> In-Reply-To: <20061013143516.15438.8802.sendpatchset@linux.site> References: <20061013143516.15438.8802.sendpatchset@linux.site> Subject: [patch 5/6] mm: debug write deadlocks Date: Fri, 13 Oct 2006 18:44:42 +0200 (CEST) Sender: owner-linux-mm@kvack.org Return-Path: To: Linux Memory Management Cc: Neil Brown , Andrew Morton , Anton Altaparmakov , Chris Mason , Linux Kernel , Nick Piggin List-ID: 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 probably needn't go upstream. Index: linux-2.6/mm/filemap.c =================================================================== --- linux-2.6.orig/mm/filemap.c +++ linux-2.6/mm/filemap.c @@ -1895,6 +1895,7 @@ 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 @@ -1902,6 +1903,7 @@ 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, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org