Re: Question on checking the stack

[Bryce <philip dot copeland at oracle dot com>]

Frank Ch. Eigler wrote:

> Bryce <philip.copeland@oracle.com> writes:
>
>  
>
> > Setting up a probe for a function is great and all but is there a way
> > to test how we entered the routine?
> > [...]
> >    
>
> Just about all the essentials are in there somewhere, just
> not in a convenient-to-use form.
>
>  
>
> > probe kernel.function("generic_make_request") {
> >    if (stack(1) == "submit_bio" ) { // where stack(1) was the last
> > routine  and stack(2) was 2nd last etc
> >         do_test/display
> >    }
> > }
> >    
>
> The tapset/context.stp file would need two new functions such as these:
>
>  caller:string(n:long) - returns the nth substring as if from backtrace()
>  addr2symbol:string(n:long) - address-to-symbol lookup, which is exactly
>                               one stage of print_stack()
>
> - FChE
>  

*nod* Just Sebastiaens hack has the unfortunate problem of needing to 
know in advance what all the exit addresses from a routine and combing 
the stack looking for a string match is probably rather slow if it 
happens often enough.

Cheers

Phil
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