Re: [PATCH v2] qemu-trace-stap: changing SYSTEMTAP_TAPSET considered harmful.

[Daniel P . Berrangé]

On Fri, Apr 09, 2021 at 12:58:10PM +0200, Gerd Hoffmann wrote:
> Setting SYSTEMTAP_TAPSET to some value other than
> /usr/share/systemtap/tapsets results in systemtap not finding the
> standard tapset library any more, which in turn breaks tracing because
> pid() and other standard systemtap functions are not available any more.
> 
> So using SYSTEMTAP_TAPSET to point systemtap to the qemu probes will
> only work for the prefix=/usr installs because both qemu and system
> tapsets in the same directory then.  All other prefixes are broken.
> 
> Fix that by using the "-I $tapsetdir" command line switch instead.

Do you know if "-I tapsetdir" appends or prepends to the search path ?

We need it to prepend to ensure that we override any QEMU stp files
that might be already present in /usr/share from an RPM provided
QEMU binary.


Regards,
Daniel
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