Re: LTTng and SystemTAP (Everyone who is scared to read this huge thread, skip to here)

From: Ingo Molnar
Date: Mon Sep 18 2006 - 11:20:16 EST



* Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx> wrote:

> > Some of the extensive hooking you do in LTT could be aleviated to a
> > great degree if you used dynamic probes. For example the syscall
> > entry hackery in LTT looks truly scary.
>
> Yes, agreed. The last time I checked, I thought about moving this
> tracing code to the syscall_trace_entry/exit (used for security hooks
> and ptrace if I remember well). I just didn't have the time to do it
> yet.

correct, that's where all such things (auditing, seccomp, ptrace,
sigstop, freezing, etc.) hook into. Much (all?) of the current entry.S
hacks can go away in favor of a much easier .c patch to
do_syscall_trace() and this would reduce a significantion portion of the
present intrusiveness of LTTng.

Ingo
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