Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933782AbXFEXAR (ORCPT ); Tue, 5 Jun 2007 19:00:17 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763433AbXFEXAF (ORCPT ); Tue, 5 Jun 2007 19:00:05 -0400 Received: from gate.crashing.org ([63.228.1.57]:41829 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759965AbXFEXAE (ORCPT ); Tue, 5 Jun 2007 19:00:04 -0400 Subject: Re: [PATCH/RFC] signal races/bugs, losing TIF_SIGPENDING and other woes From: Benjamin Herrenschmidt To: Davide Libenzi Cc: Linus Torvalds , Linux Kernel list , Andrew Morton , Paul Mackerras In-Reply-To: References: <1181006711.31677.97.camel@localhost.localdomain> <1181009413.31677.117.camel@localhost.localdomain> <1181081720.31677.144.camel@localhost.localdomain> Content-Type: text/plain Date: Wed, 06 Jun 2007 08:59:28 +1000 Message-Id: <1181084368.31677.149.camel@localhost.localdomain> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1092 Lines: 30 On Tue, 2007-06-05 at 15:50 -0700, Davide Libenzi wrote: > > What about the code in __dequeue_signal though ? That notifier thing > is > > used by the DRI though I'm not sure what would happen if it acts on > the > > wrong task. > > Hmm, looking at the comments in block_all_signals(), it seems that > they're > interested in the fact that a specific task dequeue the signal. So, > at > a first sight, it seems that such code should not not be executed if > another task dequeue the message. What do you think? Yes, I think the idea is that the DRM uses that to prevent signals to be delivered to the task that is blocking them with the notifier (I have no idea why they can't use the normal block mecanism for that... looks like a hack to me). So I suppose it's fine, as long as you add a test of tsk == current to avoid calling it. Ben. - 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/