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Re: [PATCH] Linux Kernel Markers
- From: Richard J Moore <richardj_moore at uk dot ibm dot com>
- To: Martin Bligh <mbligh at google dot com>
- Cc: Andrew Morton <akpm at osdl dot org>, Alan Cox <alan at lxorguk dot ukuu dot org dot uk>, "Frank Ch. Eigler" <fche at redhat dot com>, Greg Kroah-Hartman <gregkh at suse dot de>, Christoph Hellwig <hch at infradead dot org>, Jes Sorensen <jes at sgi dot com>, Paul Mundt <lethal at linux-sh dot org>, linux-kernel <linux-kernel at vger dot kernel dot org>, ltt-dev at shafik dot org, Mathieu Desnoyers <mathieu dot desnoyers at polymtl dot ca>, Michel Dagenais <michel dot dagenais at polymtl dot ca>, Ingo Molnar <mingo at elte dot hu>, systemtap at sources dot redhat dot com, Thomas Gleixner <tglx at linutronix dot de>, William Cohen <wcohen at redhat dot com>, Tom Zanussi <zanussi at us dot ibm dot com>
- Date: Tue, 19 Sep 2006 17:41:43 +0100
- Subject: Re: [PATCH] Linux Kernel Markers
Martin Bligh <mbligh@google.com> wrote on 19/09/2006 17:04:43:
> Frank Ch. Eigler wrote:
> > Hi -
> >
> > On Tue, Sep 19, 2006 at 08:11:40AM -0700, Martin J. Bligh wrote:
> >
> >
> >>[...] Why don't we just copy the whole damned function somewhere
> >>else, and make an instrumented copy (as a kernel module)? Then
> >>reroute all the function calls through it [...]
> >
> >
> > Interesting idea. Are you imagining this instrumented copy being
> > built at kernel compile time (something like building a "-g -O0"
> > parallel)? Or compiled anew from original sources after deployment?
> > Or on-the-fly binary-level rewriting a la SPIN?
>
> "compiled anew from original sources after deployment" seems the most
> practical to do to me. From second hand info on using systemtap, you
> seem to need the same compiler and source tree to work from anyway, so
> this doesn't seem much of a burden.
>
If I'm not mistaken, this has been done before under the guise of dynamic
patch. Doesn't Solaris have the capability? I'm certain that some UNIXes do
as well as non-UNIX O/Ss.
Richard