Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755689Ab2JPD6h (ORCPT ); Mon, 15 Oct 2012 23:58:37 -0400 Received: from mail-pb0-f46.google.com ([209.85.160.46]:61651 "EHLO mail-pb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755655Ab2JPD6g (ORCPT ); Mon, 15 Oct 2012 23:58:36 -0400 Date: Mon, 15 Oct 2012 20:58:33 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: KOSAKI Motohiro cc: Dave Jones , Linux Kernel , bhutchings@solarflare.com, linux-mm@kvack.org, Linus Torvalds , Andrew Morton Subject: Re: mpol_to_str revisited. In-Reply-To: Message-ID: References: <20121008150949.GA15130@redhat.com> User-Agent: Alpine 2.00 (DEB 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 930 Lines: 21 On Mon, 15 Oct 2012, KOSAKI Motohiro wrote: > I don't think 80de7c3138ee9fd86a98696fd2cf7ad89b995d0a is right fix. It's certainly not a complete fix, but I think it's a much better result of the race, i.e. we don't panic anymore, we simply fail the read() instead. > we should > close a race (or kill remain ref count leak) if we still have. As I mentioned earlier in the thread, the read() is done here on a task while only a reference to the task_struct is taken and we do not hold task_lock() which is required for task->mempolicy. Once that is fixed, mpol_to_str() should never be called for !task->mempolicy so it will never need to return -EINVAL in such a condition. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/