From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759420Ab1IIQ3d (ORCPT ); Fri, 9 Sep 2011 12:29:33 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53276 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758537Ab1IIQ3c (ORCPT ); Fri, 9 Sep 2011 12:29:32 -0400 Date: Fri, 9 Sep 2011 18:26:06 +0200 From: Oleg Nesterov To: Indan Zupancic Cc: Denys Vlasenko , Tejun Heo , Denys Vlasenko , linux-kernel@vger.kernel.org Subject: Re: Why I want PTRACE_O_TRACESTOP option Message-ID: <20110909162606.GC23271@redhat.com> References: <1315500802.18043.45.camel@dhcp-25-63.brq.redhat.com> <20110909001853.GA29319@htj.dyndns.org> <201109090754.50272.vda.linux@googlemail.com> <93a9bd6624aa6a991d688bfaba766a91.squirrel@webmail.greenhost.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <93a9bd6624aa6a991d688bfaba766a91.squirrel@webmail.greenhost.nl> User-Agent: Mutt/1.5.18 (2008-05-17) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 09/09, Indan Zupancic wrote: > > It is very useful to set options atomically at SEIZE time. Nobody argues with this. > Another important reason to make PTRACE_O_TRACESTOP an option is > because not everyone uses SEIZE: Users using PTRACE_TRACEME can't > set this option at all. Yes. This was already discussed, PTRACE_TRACEME obviously doesn't work if you need the new features. So far it was decided TRACEME should be avoided, but perhaps we can add SEIZE_ME. And, unlike TRACEME it should probably stop immediately to simplify the synchronization with parent. Afaik, any user of TRACEME does something like kill(getpid(), SIGSTOP), this doesn't look very good. But personally I'd prefer to avoid SEIZE_ME. Oleg.