Unfortunately the fix for the kernel bug / security hole that allowed any
process to cause a kernel panic on VAXen without compatibility mode was
incomplete.  The hole was plugged in sigreturn(2), but it is still possible to
crash the 4.3-QJ0b kernel by creating a pair of processes in ptrace(2) and
having the debugger process set PSL<CM>=1 in the traced process.

Please copy the version of sys_process.c provided here into your /sys/sys
directory and recompile your kernel.  This fixes the problem.

Only VAXen without compatibility mode are affected, i.e, 8200 and MicroVAXen.