Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755312Ab1BUOcD (ORCPT ); Mon, 21 Feb 2011 09:32:03 -0500 Received: from mx1.redhat.com ([209.132.183.28]:64639 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751268Ab1BUOcB (ORCPT ); Mon, 21 Feb 2011 09:32:01 -0500 Date: Mon, 21 Feb 2011 15:23:25 +0100 From: Oleg Nesterov To: Jan Kratochvil Cc: Denys Vlasenko , Tejun Heo , Roland McGrath , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org Subject: Re: [PATCH 1/1] ptrace: make sure do_wait() won't hang after PTRACE_ATTACH Message-ID: <20110221142325.GA16664@redhat.com> References: <20110219201603.GB8662@redhat.com> <20110219200637.GA8662@redhat.com> <20110220094050.GA7714@host1.dyn.jankratochvil.net> <20110220171658.GA27355@redhat.com> <20110220185204.GA14737@host1.dyn.jankratochvil.net> <20110220203819.GB32682@redhat.com> <20110220212053.GA23412@host1.dyn.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110220212053.GA23412@host1.dyn.jankratochvil.net> 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 Content-Length: 1365 Lines: 36 On 02/20, Jan Kratochvil wrote: > > On Sun, 20 Feb 2011 21:38:19 +0100, Oleg Nesterov wrote: > > > So. So far I assume you are not against this change ;) > > No, although you should provide the patch in advance, it would be nice to also > post it first to for comments. OK. > Now if new GDB should allow inferior functions calls on previously > `(T) stopped' process doing PTRACE_CONT(SIGCONT) No, no, this won't work. You need to send SIGCONT via kill/tkill. Once again, we can add the special case for PTRACE_CONT(SIGCONT), but please look at Roland's comment: http://marc.info/?l=linux-kernel&m=129796917823181 And given that currently gdb does PTRACE_CONT(0) this special case can't help anyway unless you change gdb. > but how to make it `(T) stopped' afterwards? PTRACE_CONT(SIGSTOP) > right after the inferior call will make the old kernels run the inferior - we > do not want that. Hmm... probably I am totally confused... but PTRACE_CONT(SIGSTOP) should work in this case, the tracee reports SIGTRAP after the single-step (if I understand correctly how gdb implements this). 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/