Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759090AbZFAUvZ (ORCPT ); Mon, 1 Jun 2009 16:51:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756207AbZFAUvR (ORCPT ); Mon, 1 Jun 2009 16:51:17 -0400 Received: from mx1.redhat.com ([66.187.233.31]:47845 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755917AbZFAUvR (ORCPT ); Mon, 1 Jun 2009 16:51:17 -0400 MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit From: Roland McGrath To: Oleg Nesterov X-Fcc: ~/Mail/linus Cc: Christoph Hellwig , Ingo Molnar , linux-kernel@vger.kernel.org Subject: Re: PATCH? tracehook_report_clone: fix false positives In-Reply-To: Oleg Nesterov's message of Monday, 1 June 2009 22:07:23 +0200 <20090601200723.GA22204@redhat.com> References: <20090528113601.GA18725@redhat.com> <20090528114100.GA18744@redhat.com> <20090528212418.2F605FC2BD@magilla.sf.frob.com> <20090529122411.GC19812@redhat.com> <20090530185212.GA10677@redhat.com> <20090601002226.480CEFC3C7@magilla.sf.frob.com> <20090601200723.GA22204@redhat.com> X-Windows: there's got to be a better way. Message-Id: <20090601205056.16307FC3C7@magilla.sf.frob.com> Date: Mon, 1 Jun 2009 13:50:56 -0700 (PDT) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1008 Lines: 28 > Oh, I never thought about attach && SIGCONT interaction... > > But, tracehook_report_clone() has the same problems? I don't follow. > And if we move sigaddset to ptrace_task_init(), we should not worry about > SIGCONT? Without CLONE_THREAD the new task is not visible to user-space yet. > Even if we clone a sub-thread, ptrace_init_task() runs under ->siglock. > If SIGCONT is already pending, copy_process() won't succeed. It could be pending and blocked. > Or do you mean something else? Sorry, I don't think I understood what your question was. I just pointed out that the element of PTRACE_ATTACH semantics that would be changed unintentionally if you just replaced its send_sig_info() call with ptrace_init_task() using sigaddset(). Thanks, Roland -- 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/