From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Mon, 27 Aug 2007 11:02:48 -0500 From: Dean Nelson Subject: [PATCH 3/4] add new lock ordering rule to mm/filemap.c Message-ID: <20070827160247.GD25589@sgi.com> References: <20070827155622.GA25589@sgi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070827155622.GA25589@sgi.com> Sender: owner-linux-mm@kvack.org Return-Path: To: akpm@linux-foundation.org Cc: linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, tony.luck@intel.com, jes@sgi.com List-ID: This patch adds a lock ordering rule to avoid a potential deadlock when multiple mmap_sems need to be locked. Signed-off-by: Dean Nelson Index: linux-2.6/mm/filemap.c =================================================================== --- linux-2.6.orig/mm/filemap.c 2007-08-09 19:18:15.000000000 -0500 +++ linux-2.6/mm/filemap.c 2007-08-27 09:13:47.435717670 -0500 @@ -78,6 +78,9 @@ * ->i_mutex (generic_file_buffered_write) * ->mmap_sem (fault_in_pages_readable->do_page_fault) * + * When taking multiple mmap_sems, one should lock the lowest-addressed + * one first proceeding on up to the highest-addressed one. + * * ->i_mutex * ->i_alloc_sem (various) * -- 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