dtrace stored its PR_RLC and PR_KLC flags in the proc_handle's flags, where they collided with PATTACH_FORCE and PATTACH_RDONLY, respectively. Thus, Psetflags(PR_KLC) effectively also set the PATTACH_RDONLY flag.
Since the flags are private to dtrace (at least on FreeBSD), store them in dtrace's own dt_proc structure instead.
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