From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932286AbVKFFVk (ORCPT ); Sun, 6 Nov 2005 00:21:40 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932293AbVKFFVk (ORCPT ); Sun, 6 Nov 2005 00:21:40 -0500 Received: from omx2-ext.sgi.com ([192.48.171.19]:34004 "EHLO omx2.sgi.com") by vger.kernel.org with ESMTP id S932286AbVKFFVk (ORCPT ); Sun, 6 Nov 2005 00:21:40 -0500 Date: Sat, 5 Nov 2005 21:21:33 -0800 From: Paul Jackson To: Andi Kleen Cc: akpm@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Does shmem_getpage==>shmem_alloc_page==>alloc_page_vma hold mmap_sem? Message-Id: <20051105212133.714da0d2.pj@sgi.com> Organization: SGI X-Mailer: Sylpheed version 2.0.0beta5 (GTK+ 2.4.9; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Andi, The comment in mm/mempolicy.c for alloc_page_vma() states: Should be called with the mm_sem of the vma hold. However it seems that the call chain (#ifdef CONFIG_NUMA): shmem_getpage ==> shmem_alloc_page ==> alloc_page_vma where shmem_getpage() is called from many of the mm/shmem.c file operations, is called without holding mmap_sem. There is no mention of mmap_sem in the entire mm/shmem.c file. This doesn't seem right. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.925.600.0401