This is the mail archive of the systemtap@sourceware.org mailing list for the systemtap project.


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]
Other format: [Raw text]

Re: rprobes + Function return probes status


Rick Salmon Vishwanath <maveriickk@yahoo.com> writes:

> [...]  I am basically looking for a maechanism that would let me log
> the arguments of a function call(jprobes-like) and the return value
> of the function(kretprobes-like) simultaneously. [...]

Currently, this requires two separate probes, with the first
triggering near function entry to save incoming parameters, and the
second triggering upon function return.  This can be done now with
some combination of jprobes & kretprobes, if that is your kind of
poison, or alternately in systemtap script.  In each case, the tricky
part is saving the incoming parameters, then finding them again, while
dodging obstacles like recursion and concurrency.  This part has to be
done manually right now.

The systemtap translator is planned to support performing the
save/restore automagically (bug #1382), so that a single specially
marked "return" probe would have transparent access to the saved
copies of parameters.

- FChE


Index Nav: [Date Index] [Subject Index] [Author Index] [Thread Index]
Message Nav: [Date Prev] [Date Next] [Thread Prev] [Thread Next]