Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757166AbaDHQMs (ORCPT ); Tue, 8 Apr 2014 12:12:48 -0400 Received: from mx1.redhat.com ([209.132.183.28]:32447 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757055AbaDHQMq (ORCPT ); Tue, 8 Apr 2014 12:12:46 -0400 Date: Tue, 8 Apr 2014 18:10:20 +0200 From: Oleg Nesterov To: Masami Hiramatsu Cc: Ingo Molnar , Srikar Dronamraju , Ananth N Mavinakayanahalli , Anton Arapov , David Long , Denys Vlasenko , "Frank Ch. Eigler" , Jim Keniston , Jonathan Lebon , linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 6/9] uprobes/x86: Introduce uprobe_xol_ops and arch_uprobe->ops Message-ID: <20140408161020.GB31460@redhat.com> References: <20140404185131.GA14738@redhat.com> <5343BCF0.3030605@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <5343BCF0.3030605@hitachi.com> 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 04/08, Masami Hiramatsu wrote: > > (2014/04/05 3:51), Oleg Nesterov wrote: > > > > TODO: An error from adjust_ret_addr() shouldn't be silently ignored, > > we should teach arch_uprobe_post_xol() or handle_singlestep() paths > > to restart the probed insn in this case. And probably "adjust" can > > be simplified and turned into set_ret_addr(). It seems that we do > > not really need copy_from_user(), we can always calculate the value > > we need to write into *regs->sp. > > It seems that you fixed this in 8/9, we don't need the TODO list in > the description. Well, OK, I'll update the changelog and remove the "error ... ignored" part. Although to be honest, I do not understand why do you think it is bad to document the other problems you found while you were writing the patch. > > + if (auprobe->ops->emulate) > > + return auprobe->ops->emulate(auprobe, regs); > > + > > + /* TODO: move this code into ->emulate() hook */ > > If you think this can move into the emulate(), Yes sure, > you should do in this > patch. No, sorry, I strongly disagree, this should come as a separate change, and only after "Emulate jmp's". > Since the following code runs by default, there should be > no problem to do that. Hmm. Not sure I understand "by default". If you meant that this should go into default_emulate_op() (which we do not have), then I strongly disagree again. It should not, if nothing else we need to record insn->length somewhere, this should go into ttt_emulate_op() we add later. And it simply looks much more natural to handle jmp's and nop's together. Masami, this time I simply can't understand your objections, please clarify. Thanks, 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/