Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757447AbYA0PeM (ORCPT ); Sun, 27 Jan 2008 10:34:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753980AbYA0PeB (ORCPT ); Sun, 27 Jan 2008 10:34:01 -0500 Received: from rv-out-0910.google.com ([209.85.198.186]:40495 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751974AbYA0PeA (ORCPT ); Sun, 27 Jan 2008 10:34:00 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=cDLJENhlfW0NrBCP/mRyrRnfT6US8zHLYBJM9Kv8Z2bUVemYeJhuWZZgWcdu326krgfK0CM225w/RBbmsAsrGuOezSyF4dU6msFKULNxjtDhukW+y32tfAfSaJ4y6GDmGtRnRiwNrJMAgrlKQ/4g2T3vGoq6rTK326+dCsy8pws= Message-ID: <863e9df20801270733n4b82b595u8421fb07c18acaa6@mail.gmail.com> Date: Sun, 27 Jan 2008 21:03:58 +0530 From: "Abhishek Sagar" To: "Masami Hiramatsu" Subject: Re: [PATCH 3/3] x86: WARN_ON breakpoints from .kprobes.text section Cc: LKML , jkenisto@us.ibm.com, ananth@in.ibm.com, "Ingo Molnar" In-Reply-To: <479C94F6.2070502@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <479C4A4F.10604@gmail.com> <479C94F6.2070502@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1159 Lines: 30 On 1/27/08, Masami Hiramatsu wrote: > Sorry, I can not understand what issue these patches can solve. > The breakpoint which is inserted by external debugger will be checked by > kprobe_handler() and be passed to other exception_notify_handlers. > In that case, we don't need to warn it. > I think current code is enough simple. kprobe_handler has a blanket check for all non-kprobe breakpoints. They're all left to the kernel to handle. This is fine. Although external debuggers are free to plant breakpoints anywhere, they should be discouraged from doing so inside .kprobes.text region. Placing them there may lead to recursive page-fault/trap handling. It's a defensive check. I hope I've been able to clarify. > -- > Masami Hiramatsu > > Software Engineer > Hitachi Computer Products (America) Inc. > Software Solutions Division > > e-mail: mhiramat@redhat.com Thanks, Abhishek Sagar -- 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/