From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Pekka Enberg" Subject: Re: msync(2) bug(?), returns AOP_WRITEPAGE_ACTIVATE to userland Date: Sat, 13 Oct 2007 00:45:48 +0300 Message-ID: <84144f020710121445p23fcc21am18482e01856cdc35@mail.gmail.com> References: <200710071920.l97JKJX5018871@agora.fsl.cs.sunysb.edu> <20071011144740.136b31a8.akpm@linux-foundation.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: "Ryan Finnie" , "Andrew Morton" , "Erez Zadok" , linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, cjwatson@ubuntu.com, linux-mm@kvack.org To: "Hugh Dickins" Return-path: Received: from rv-out-0910.google.com ([209.85.198.186]:45884 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760256AbXJLVpt (ORCPT ); Fri, 12 Oct 2007 17:45:49 -0400 Received: by rv-out-0910.google.com with SMTP id k20so902405rvb for ; Fri, 12 Oct 2007 14:45:48 -0700 (PDT) In-Reply-To: Content-Disposition: inline Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-fsdevel.vger.kernel.org Hi Hugh, On 10/12/07, Hugh Dickins wrote: > But I keep suspecting that the answer might be the patch below (which > rather follows what drivers/block/rd.c is doing). I'm especially > worried that, rather than just AOP_WRITEPAGE_ACTIVATE being returned > to userspace, bad enough in itself, you might be liable to hit that > BUG_ON(page_mapped(page)). shmem_writepage does not expect to be > called by anyone outside mm/vmscan.c, but unionfs can now get to it? Doesn't msync(2) get to it via mm/page-writeback.c:write_cache_pages() without unionfs even? Pekka