Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932160AbWCOBM1 (ORCPT ); Tue, 14 Mar 2006 20:12:27 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932179AbWCOBM1 (ORCPT ); Tue, 14 Mar 2006 20:12:27 -0500 Received: from saraswathi.solana.com ([198.99.130.12]:10400 "EHLO saraswathi.solana.com") by vger.kernel.org with ESMTP id S932160AbWCOBM0 (ORCPT ); Tue, 14 Mar 2006 20:12:26 -0500 Date: Tue, 14 Mar 2006 20:13:12 -0500 From: Jeff Dike To: Pavel Machek Cc: Chuck Ebbert <76306.1226@compuserve.com>, linux-kernel , Roland McGrath , Linus Torvalds Subject: Re: What is ptrace flag PT_TRACESYSGOOD for? Message-ID: <20060315011312.GA9410@ccure.user-mode-linux.org> References: <200603140531_MC3-1-BAA0-B3C3@compuserve.com> <20060314230056.GA1579@elf.ucw.cz> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060314230056.GA1579@elf.ucw.cz> User-Agent: Mutt/1.4.2.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 746 Lines: 17 On Wed, Mar 15, 2006 at 12:00:56AM +0100, Pavel Machek wrote: > Yes.. and unless you deliver ptrace() syscall stops with different > signal, you can't tell difference between syscall stop and real > SIGTRAP. You can, but you have to examine registers in order to do this. This is a concern when running gdb inside UML. gdb breakpoints will cause real SIGTRAPs, while system calls cause synthetic ones. Before switching to TRACESYS_GOOD, UML examined orig_eax to distinguish between them. Jeff - 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/