From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx138.postini.com [74.125.245.138]) by kanga.kvack.org (Postfix) with SMTP id A94B96B0044 for ; Tue, 1 May 2012 02:49:56 -0400 (EDT) Received: by obbwd18 with SMTP id wd18so2977660obb.14 for ; Mon, 30 Apr 2012 23:49:55 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <1335778207-6511-1-git-send-email-jack@suse.cz> References: <1335778207-6511-1-git-send-email-jack@suse.cz> Date: Tue, 1 May 2012 16:49:55 +1000 Message-ID: Subject: Re: [PATCH] Describe race of direct read and fork for unaligned buffers From: Nick Piggin Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: Jan Kara Cc: Michael Kerrisk , LKML , linux-man@vger.kernel.org, linux-mm@kvack.org, mgorman@suse.de, Jeff Moyer On 30 April 2012 19:30, Jan Kara wrote: > This is a long standing problem (or a surprising feature) in our implementation > of get_user_pages() (used by direct IO). Since several attempts to fix it > failed (e.g. > http://linux.derkeiler.com/Mailing-Lists/Kernel/2009-04/msg06542.html, or > http://lkml.indiana.edu/hypermail/linux/kernel/0903.1/01498.html refused in > http://comments.gmane.org/gmane.linux.kernel.mm/31569) and it's not completely > clear whether we really want to fix it given the costs, let's at least document > it. In any case, it should be documented even if it is ever fixed in newer kernels. Thanks! -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org