Hi Thomas,

Thanks for the debug data - I think I know what's going
on now (for those who are wondering - I contacted
Thomas offline to get some debug and ask some questions).

> I get this strange behavior when (as non-root with dtrace-proc and 
> dtrace-user privs) I try to trace a process in a non-global zone (running 
> there under my account, same privs) from the global zone.
>
> This already is my "fallback" path, because my first attempt (to do the 
> tracing in the non-global zone where the process is running) failed with 
> "dtrace: failed to initialize dtrace: DTrace device not available in local 
> zone"

DTrace doesn't work in a zone until Solaris 10 08/07 so that's
why you're seeing this (I believe you're running Solaris 10 11/06).

> I get the same effect with a variant of the classic "hello, world"-program 
> when trying to trace it in the same manner (cross-zone, as described above).
> But everything works as expected when I'm running both the "hello, 
> world"-program and dtrace in the global zone.
> Unfortunately running the server-process in the global-zone isn't a 
> practicable path, because this process depends heavy on the versions of 
> installed third-party libraries, which differ between the zones.

The reason why you're seeing this is NFS (NFS experts correct me
if I'm wrong here). I understand that the failure cases occur when
the binaries are located in an NFS mount in the non-global zone.
In the current implementation a zone cannot access files associated
with NFS mounts in other zones and this includes the global zone.
Therefore when process X runs in zone Y we cannot access its constituent
files for pertinent debug data from another zone even if that is the
global zone.

I think this screws you for debugging objects which are running from
non-global zone based NFS mounts but doing the debugging in the
global zone. I think you have two solutions:

1) Upgrade to a later update of Solaris 10 and then you can do
your debugging all in the non-global zone.
2) Run off local filesystems in the non-global zone.

Let me know if you have any questions (or anyone with NFS/Zone
expertise feel free to chip in here).

Jon.
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