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Re: Kprobes support for accessing args upon return
- From: fche at redhat dot com (Frank Ch. Eigler)
- To: Jim Keniston <jkenisto at us dot ibm dot com>
- Cc: SystemTAP <systemtap at sources dot redhat dot com>
- Date: 06 Dec 2006 21:35:56 -0500
- Subject: Re: Kprobes support for accessing args upon return
- References: <1165444360.2874.18.camel@dyn9047018079.beaverton.ibm.com>
Jim Keniston <jkenisto@us.ibm.com> writes:
> As promised, here (once again) is a pointer to the kretprobes patch
> (against 2.6.13) that adds an optional "data pouch" to a
> kretprobe_instance. [....]
The main problem with this has been that, at the point where the entry
half of the kretprobe fires, we may not have good quality debugging
information to let us symbolically locate all the needed arguments.
So, unfortunately, we currently use a normal, post-prologue kprobe to
collect them.
> The patch itself is quite simple, as you can see. How to express
> this feature in the SystemTap language was never nailed down.
It seems to me that the current (new) syntax could work unchanged
for this alternate backend.
- FChE