Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932214AbWIKC7p (ORCPT ); Sun, 10 Sep 2006 22:59:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932215AbWIKC7o (ORCPT ); Sun, 10 Sep 2006 22:59:44 -0400 Received: from taganka54-host.corbina.net ([213.234.233.54]:19133 "EHLO mail.screens.ru") by vger.kernel.org with ESMTP id S932214AbWIKC7o (ORCPT ); Sun, 10 Sep 2006 22:59:44 -0400 Date: Mon, 11 Sep 2006 06:59:40 +0400 From: Oleg Nesterov To: "Eric W. Biederman" Cc: Andrew Morton , linux-kernel@vger.kernel.org, Linux Containers , Alan Cox Subject: Re: [PATCH] vt: Rework the console spawning variables. Message-ID: <20060911025940.GA7216@oleg> References: <20060910142942.GA7384@oleg> <20060910203324.GA121@oleg> <20060911010534.GA108@oleg> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 929 Lines: 29 On 09/10, Eric W. Biederman wrote: > > Oleg Nesterov writes: > > > On 09/10, Eric W. Biederman wrote: > >> > >> Updating this old code is painful. > > > > No, no, we shouldn't change the old code, it is fine. > > > So what happens when: > cpu0: cpu1: > kill_pid(vt_pid,....) fn_SAK()->vc_reset()->put_pid(xchg(&vt_pid, NULL)) > > Can't kill_pid dereference vt_pid after put_pid is called? Ah, I didn't consider that patch as 'old code', sorry :) I don't understand drivers/char/vt*, but surely put_pid(xchg()) can't work. Again, unless we have a lock to serialize access to ->vt_pid, but in that case we don't need xchg(). Oleg. - 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/