Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760677AbYB1Pk6 (ORCPT ); Thu, 28 Feb 2008 10:40:58 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757500AbYB1Pkv (ORCPT ); Thu, 28 Feb 2008 10:40:51 -0500 Received: from styx.suse.cz ([82.119.242.94]:34294 "EHLO mail.suse.cz" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1757253AbYB1Pku (ORCPT ); Thu, 28 Feb 2008 10:40:50 -0500 Date: Thu, 28 Feb 2008 16:40:49 +0100 (CET) From: Jiri Kosina To: Oleg Nesterov cc: Roland McGrath , Davide Libenzi , Andrew Morton , linux-kernel@vger.kernel.org Subject: Re: [PATCH] [RFC] fix missed SIGCONT cases In-Reply-To: <20080228153043.GA11484@tv-sign.ru> Message-ID: References: <20080227210038.93AFC2700FD@magilla.localdomain> <20080228102649.071572700FD@magilla.localdomain> <20080228153043.GA11484@tv-sign.ru> 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: 1321 Lines: 34 On Thu, 28 Feb 2008, Oleg Nesterov wrote: > BTW, I think we have the same problem when handle_stop_signal() does > do_notify_parent_cldstop(p, CLD_STOPPED) above. The multithreaded app in > the middle of the group stop can resume without actually seeing SIGCONT, > no? Yes, I think so, this would also need fixing. > Currently I have the very vagues idea, please see the "patch" below (it > is not right of course, just for illustration). > These unlock(->siglock)'s on the signal sending path are really nasty, > it would be wonderfull to avoid them. Note also sig_needs_tasklist(), > we take tasklist_lock() exactly because we will probably drop siglock. Whould it be problematic to change do_notify_parent_cldstop() so that it doesn't acquire siglock, but asumes that is is called with siglock held instead? I can't immediately see any reason why this shouldn't be possible. > What do you think about the approach at least? So it basically does the same thing my patch did -- postpones signalling the parent until it is safe, right? Thanks, -- Jiri Kosina -- 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/