db> show active trace

Tracing command kernel pid 0 tid 100121 td 0xffffffc0abf62b80 (CPU 2)
ipi_stop() at ipi_stop+0x2c
intr_ipi_dispatch() at intr_ipi_dispatch+0x3c
sbi_ipi_intr() at sbi_ipi_intr+0x70
intr_event_handle() at intr_event_handle+0x84
intr_isrc_dispatch() at intr_isrc_dispatch+0x2a
intc_intr() at intc_intr+0x3e
intr_irq_handler() at intr_irq_handler+0x52
do_trap_supervisor() at do_trap_supervisor+0x5e
cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x74
--- interrupt 1
memmove() at memmove+0xd6
.L0 () at .L0 +0x8
.L0 () at .L0 +0x2
.L0 () at .L0 +0x4
.L0 () at .L0
.L0 () at .L0 +0x6
$x() at $x+0x4e
taskqueue_thread_loop() at taskqueue_thread_loop+0x142
$x() at $x+0x14
fork_trampoline() at fork_trampoline+0xa

Tracing command kernel pid 0 tid 100122 td 0xffffffc0abf625c0 (CPU 3)
ipi_stop() at ipi_stop+0x2c
intr_ipi_dispatch() at intr_ipi_dispatch+0x3c
sbi_ipi_intr() at sbi_ipi_intr+0x70
intr_event_handle() at intr_event_handle+0x84
intr_isrc_dispatch() at intr_isrc_dispatch+0x2a
intc_intr() at intc_intr+0x3e
intr_irq_handler() at intr_irq_handler+0x52
do_trap_supervisor() at do_trap_supervisor+0x5e
cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x74
--- interrupt 1
memmove() at memmove+0xd6
.L0 () at .L0 +0x8
.L0 () at .L0 +0x2
.L0 () at .L0 +0x4
.L0 () at .L0
.L0 () at .L0 +0x6
$x() at $x+0x4e
taskqueue_thread_loop() at taskqueue_thread_loop+0x142
$x() at $x+0x14
fork_trampoline() at fork_trampoline+0xa

Tracing command kernel pid 0 tid 100123 td 0xffffffc0abf62000 (CPU 0)
ipi_stop() at ipi_stop+0x2c
intr_ipi_dispatch() at intr_ipi_dispatch+0x3c
sbi_ipi_intr() at sbi_ipi_intr+0x70
intr_event_handle() at intr_event_handle+0x84
intr_isrc_dispatch() at intr_isrc_dispatch+0x2a
intc_intr() at intc_intr+0x3e
intr_irq_handler() at intr_irq_handler+0x52
do_trap_supervisor() at do_trap_supervisor+0x5e
cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x74
--- interrupt 1
.L0 () at .L0
.L0 () at .L0 +0x4
.L0 () at .L0 +0x2
.L0 () at .L0 +0xe
.L0 () at .L0 +0x6
.L0 () at .L0 +0x6
.L0 () at .L0 +0x6
$x() at $x+0x4e
taskqueue_thread_loop() at taskqueue_thread_loop+0x142
$x() at $x+0x14
fork_trampoline() at fork_trampoline+0xa

Tracing command idle pid 11 tid 100004 td 0xffffffc0abe01700 (CPU 1)
kdb_enter() at kdb_enter+0x38
vpanic() at vpanic+0x19a
panic() at panic+0x26
kdb_alt_break_internal() at kdb_alt_break_internal+0x90
kdb_alt_break() at kdb_alt_break+0xe
uart_intr_rxready() at uart_intr_rxready+0x7e
uart_intr() at uart_intr+0x104
intr_event_handle() at intr_event_handle+0x84
intr_isrc_dispatch() at intr_isrc_dispatch+0x2a
plic_intr() at plic_intr+0x80
intr_event_handle() at intr_event_handle+0x84
intr_isrc_dispatch() at intr_isrc_dispatch+0x2a
intc_intr() at intc_intr+0x3e
intr_irq_handler() at intr_irq_handler+0x52
do_trap_supervisor() at do_trap_supervisor+0x5e
cpu_exception_handler_supervisor() at cpu_exception_handler_supervisor+0x74
--- interrupt 9
cpu_idle() at cpu_idle+0x5e
$x() at $x+0x1e8
$x() at $x+0x14
fork_trampoline() at fork_trampoline+0xa