The green threads implementation for Solaris interposes a layer between native code a several library functions. Among these is dlsym(). In the case where native code attempts to utilize dlsym with an arg of RTLD_NEXT ie.
NextFunction = dlsym (RTLD_NEXT, "Function" ) the implementation returns the wrong value if the caller is in a different .so from the usurper. Thus if one wants to usurp a native function such as:

LibFunction( int x )
{
if (x < 0 )
gowild();
OriginalLibFunction = dlsym( RLTD_NEXT, "LibFunction" );
(*OriginalLibFunction)(x);
etc...

OldSomeLibFunction winds up equal to SomeLibFunction and as a result causes an infinite loop ultimately crashing the vm.