12:04:36stassatsvm_prot_none doesn't help, but, OS_VM_PROT_WRITE does end up with Received signal 11 in non-lisp thread 9219342400, resignalling to a lisp thread.
12:08:02stassatsso, some OS thread is touching a thread corpse inappropriately
12:30:02stassatsthe foreign thread may actually be a newly dead lisp thread