Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932655AbVKIRzh (ORCPT ); Wed, 9 Nov 2005 12:55:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932630AbVKIRzh (ORCPT ); Wed, 9 Nov 2005 12:55:37 -0500 Received: from mailout1.vmware.com ([65.113.40.130]:57609 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S932655AbVKIRzg (ORCPT ); Wed, 9 Nov 2005 12:55:36 -0500 Message-ID: <43723768.2060103@vmware.com> Date: Wed, 09 Nov 2005 09:52:40 -0800 From: Zachary Amsden User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040803 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ingo Molnar Cc: Andi Kleen , virtualization@lists.osdl.org, Andrew Morton , Chris Wright , Linus Torvalds , Linux Kernel Mailing List , "H. Peter Anvin" , Zwane Mwaikambo , Martin Bligh , Pratap Subrahmanyam , Christopher Li , "Eric W. Biederman" , prasanna@in.ibm.com, ananth@in.ibm.com, anil.s.keshavamurthy@intel.com, davem@davemloft.net Subject: Re: [PATCH 19/21] i386 Kprobes semaphore fix References: <200511080439.jA84diI6009951@zach-dev.vmware.com> <200511081412.05285.ak@suse.de> <4370A9F5.4060103@vmware.com> <200511091438.11848.ak@suse.de> <437227FD.6040905@vmware.com> <20051109165804.GA15481@elte.hu> In-Reply-To: <20051109165804.GA15481@elte.hu> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-OriginalArrivalTime: 09 Nov 2005 17:52:41.0327 (UTC) FILETIME=[615B9FF0:01C5E556] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1036 Lines: 32 Ingo Molnar wrote: >* Zachary Amsden wrote: > > > >>>I believe user space kprobes are being worked on by some IBM India folks >>>yes. >>> >>> >>I'm convinced this is pointless. What does it buy you over a ptrace >>based debugger? Why would you want extra code running in the kernel >>that can be done perfectly well in userspace? >> >> > >kprobes are not just for 'debuggers', they are also used for tracing and >other dynamic instrumentation in projects like systemtap. Ptrace is way >too slow and limited for things like that. > > Well, if there is a justification for it, that means we really should handle all the nasty EIP conversion cases due to segmentation and v8086 mode in the kprobes code. I was hoping that might not be the case. Zach - 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/