On Mon, 02 Dec 2019 21:58:36 +0100, Mark Johnston <markj at freebsd.org> wrote: > The DTRACE_PROBE* macros cast their parameters to uintptr_t, which > will be 32 bits wide on i386. You might be able to work around the > problem by casting arg0 to uint32_t in the script. Thanks for the info - good that it has a logical explanation.