From mboxrd@z Thu Jan 1 00:00:00 1970 From: Andrea Arcangeli Subject: [ofa-general] [PATCH 8 of 8] This patch adds a lock ordering rule to avoid a potential deadlock when Date: Wed, 02 Apr 2008 23:30:09 +0200 Message-ID: References: Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: general-bounces@lists.openfabrics.org Errors-To: general-bounces@lists.openfabrics.org To: akpm@linux-foundation.org Cc: Nick Piggin , Peter Zijlstra , linux-mm@kvack.org, Izik Eidus , Kanoj Sarcar , Roland Dreier , Jack Steiner , linux-kernel@vger.kernel.org, Avi Kivity , kvm-devel@lists.sourceforge.net, Robin Holt , general@lists.openfabrics.org, Christoph Lameter List-Id: linux-mm.kvack.org # HG changeset patch # User Andrea Arcangeli # Date 1207159059 -7200 # Node ID f3f119118b0abd9c4624263ef388dc7230d937fe # Parent 31fc23193bd039cc595fba1ca149a9715f7d0fb2 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 diff --git a/mm/filemap.c b/mm/filemap.c --- a/mm/filemap.c +++ b/mm/filemap.c @@ -79,6 +79,9 @@ * * ->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)