Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753933Ab3HERjR (ORCPT ); Mon, 5 Aug 2013 13:39:17 -0400 Received: from mail-vb0-f54.google.com ([209.85.212.54]:37075 "EHLO mail-vb0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752127Ab3HERjQ (ORCPT ); Mon, 5 Aug 2013 13:39:16 -0400 MIME-Version: 1.0 In-Reply-To: <20130805132948.GA14942@redhat.com> References: <20130805132948.GA14942@redhat.com> Date: Mon, 5 Aug 2013 10:39:15 -0700 X-Google-Sender-Auth: qJX02TvNBDFtSbvSe1jP06AQWns Message-ID: Subject: Re: Linux 3.11-rc4 From: Linus Torvalds To: Oleg Nesterov Cc: Felipe Contreras , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1046 Lines: 24 On Mon, Aug 5, 2013 at 6:29 AM, Oleg Nesterov wrote: > > I never used wine, but I am puzzled anyway. This patch really looks > like a simple and minor bugfix. The patch is indeed trivial, but.. What's the locking here? Afaik, ptrace_detach() by the parent can race with do_exit() by the child, and they now _both_ do flush_ptrace_hw_breakpoint(). Or am I wrong? We have that whole "get tasklist_lock for writing and then check child->ptrace" logic there exactly due to that race, no? That said, Felipe, can you double-check that it's not timing-related in some subtle way, and test multiple times with just that commit reverted (and not reverted) to make sure that it's 100% that one single line by that particular commit? Because it does seem very benign.. Linus -- 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/