From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 10652 invoked by alias); 27 Jul 2005 13:02:00 -0000 Mailing-List: contact systemtap-help@sources.redhat.com; run by ezmlm Precedence: bulk List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sources.redhat.com Received: (qmail 10628 invoked by uid 22791); 27 Jul 2005 13:01:50 -0000 Message-ID: <42E785C2.3070606@sdl.hitachi.co.jp> Date: Wed, 27 Jul 2005 13:02:00 -0000 From: Masami Hiramatsu User-Agent: Mozilla Thunderbird 1.0.5 (Windows/20050711) X-Accept-Language: en-us, en MIME-Version: 1.0 To: Roland McGrath Cc: Richard J Moore , SystemTAP , sugita@sdl.hitachi.co.jp, Satoshi Oshima Subject: Re: Hitachi djprobe mechanism References: <20050726075346.F2D811809B2@magilla.sf.frob.com> In-Reply-To: <20050726075346.F2D811809B2@magilla.sf.frob.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-SW-Source: 2005-q3/txt/msg00125.txt.bz2 Hi, Roland Roland McGrath wrote: >> I think Kerninst is similar in effect to djprobe. both of them copy >>original code to a buffer and jump to the buffer. >> However I think that the most unique feature of djprobe is use of >>"bypass" route to safely insert code on SMP. >> I cannot find SMP safety mechanism like "bypass" in kerninst papers >>yet. > > > If by this you mean inserting an int3 while writing the rest of the jmp > instruction and then overwriting the first byte when the rest is in place, > I recall reading about that in some kerninst paper to be sure. Thanks a lot. Finally, I found it in page.9 of the OSDI paper: "Fine-Grained Dynamic Instrumentation of Commodity Operating System Kernels", Ariel Tamches and Barton P. Miller, OSDI, Feb 1999. Actually, it seems to describe a similar thing. -- Masami HIRAMATSU 2nd Research Dept. Hitachi, Ltd., Systems Development Laboratory E-mail: hiramatu@sdl.hitachi.co.jp