Re: vfs tapset compilation error.

[Josh Stone <jistone at redhat dot com>]

On 01/25/2011 03:59 PM, Mark Wielaard wrote:
> Although it seems my patch works, and we do scan fewer files if an
> include dir happens to be included multiple times, I am still a little
> confused how this can happen. This issue should already have been dealt
> with through: http://sourceware.org/bugzilla/show_bug.cgi?id=11949
> 
> Do you have the following commit included in your build?
> 
> commit ad7c8e4393af112099a0ab3c54e3b49056ef6289
> Author: Frank Ch. Eigler <fche@elastic.org>
> Date:   Thu Aug 26 18:30:28 2010 -0400
> 
>     PR11949: duplicate-eliminate tapset files

Daniel's stap-report says version 1.3, which came out in July.  We went
a long time between releases for 1.4, which finally included this fix.
And see his other mail which shows that stap.git indeed processes
nothing from the duplicate path.

We can still have a problem though, e.g. if XDG_DATA_DIRS=/usr/share,
but you're trying to run /usr/local/bin/stap (or /opt, etc.)

I think we need a way to mark that certain paths should only be included
via the main tapset path (PREFIX/systemtap/tapset or SYSTEMTAP_TAPSET).
 There are many means, but perhaps something like just an empty
".systemtap_tapset" file could indicate that this path should not be
searched via -I or XDG_DATA_DIRS.

You'd have to manually add this to old installations in order to get
newer staps to ignore such paths, but at least this is a possible
workaround.  Any other ideas?


Josh