panic: mi_switch: did not reenter debugger

-current updated a few hours ago:

# sysctl debug.kdb.stop_cpus=0
debug.kdb.stop_cpus: 1 -> 0
# ~KDB: enter: Break sequence on console
[thread pid 11 tid 100004 ]
Stopped at      kdb_enter+0x32: leal    0(%esi),%esi
db> cont
KDB: stack backtrace:
^Bmi_switch(2,0,c06e7f4b,24f,0) at mi_switch+0x31d
critical_exit(c0734020,24d,0,ea07ec60,c347f730) at critical_exit+0xd3
intr_execute_handlers(c0734020,ea07ec78,c3504d00,ea07ec70,0) at intr_execute_handlers+0x130
atpic_handle_intr(0) at atpic_handle_intr+0x53
Xatpic_intr0() at Xatpic_intr0+0x20
--- interrupt, eip = 0xc0691855, esp = 0xea07ecbc, ebp = 0xea07ecbc ---
acpi_cpu_c1(c347f730,fffffffe,0,ea07ece4,c051d4f2) at acpi_cpu_c1+0x5
acpi_cpu_idle(c073e9c0,2,c06e437c,73,c06e7f4b) at acpi_cpu_idle+0x180
idle_proc(0,ea07ed48,c06e4254,30e,ffffffff) at idle_proc+0x95
fork_exit(c04f1c80,0,ea07ed48) at fork_exit+0xa9
fork_trampoline() at fork_trampoline+0x8
--- trap 0x1, eip = 0, esp = 0xea07ed7c, ebp = 0 ---
panic: mi_switch: did not reenter debugger
cpuid = 0
KDB: enter: panic
[thread pid 12 tid 100005 ]
Stopped at      kdb_enter+0x32: leal    0(%esi),%esi

kris