Re: kern/50700: dtrace module(s) cannot be loaded

[christos%zoulas.com@localhost (Christos Zoulas)]

On Jan 25,  5:59am, paul%whooppee.com@localhost (Paul Goyette) wrote:
-- Subject: Re: kern/50700: dtrace module(s) cannot be loaded

| No.
| 
| If everything is built-in (ie, KDTRACE_HOOKS is defined), there is no 
| problem.  the module doesn't need to "load" since it is already 
| built-in.

No, KDTRACE_HOOKS does not actually make everything built-in. It just
adds the hooks that dtrace needs to link if it is loaded.

| The problem occurs when the module is NOT built-in, ie, KDTRACE_HOOKS is 
| not defined.

If KDTRACE_HOOKS are not defined, then the modules cannot load since the
support for them is missing from the kernel.

| In this case, the modules that are built are not "complete".  They don't 
| contain critical trap/vector "support-code", and they don't contain the 
| various "probes".  The lack of support-code prevents them from even 
| being loaded (due to the error messages reported in the PR).

That's a different story. We currently don't have modules that have probes,
and we would need to have a module notification system for that to work
properly (load the probes when the module is loaded and unload them before
it is unloaded).

| Even if the support-code issue were resovled (by including it in all 
| kernels, unconditionally), the load-at-run-time modules would be of no 
| value, since none of the "probes" would exist.

The probes are compiled in when KDTRACE_HOOKS is defined.

christos