Re: What can I access in return probe

[Kevin Stafford <kevinrs at us dot ibm dot com>]

Kevin Stafford wrote:

> Badari Pulavarty wrote:
>
> > Hi,
> >
> > I am wondering if I can access arguments in my return probe ?
> >  
> No, by the time the return probe fires, the stack has been torn down 
> and thus
> have no reference to you arguments, which causes the deref fault. 
> There have
> been a couple of proposed solutions to this problem. See
> http://sources.redhat.com/bugzilla/show_bug.cgi?id=1382
>
> > And also, how do I access return value ?
> >  
> Tapset function retval() should do this for you.
> See /usr/local/share/systemtap/tapset/return.stp
>
> > Whats wrong here ?
> >
> > # stap -g pagecache.stp
> > ERROR: pointer dereference fault near identifier 'page_cache_pages' at
> > pagecache.stp:8:2
> >
> >
> > Thanks,
> > Badari
> >  


--
Kevin Stafford
DES 2 | MS 2M3
Beaverton - OR
Linux Technology Center
IBM Systems & Technology
Phone: 1-503-578-3039
Email: kevinrs@us.ibm.com