gtq_null: racer/detacher running, expect panic
gtask: 0xffffffff82601280 ta_flags=0 ta_priority=0 ta_func=0xffffffff82601000 ta_context=0
panic: queue == NULL
cpuid = 1
Trace beginning at frame 0xfffff80118abfa60
grouptaskqueue_enqueue() at grouptaskqueue_enqueue+0x11d 0xffffffff806a582d 
grouptaskqueue_enqueue() at grouptaskqueue_enqueue+0x11d 0xffffffff806a582d 
racer() at racer+0x2f 0xffffffff826010af 
Debugger("panic")

CPU1 stopping CPUs: 0x0000003d
 stopped
Stopped at      Debugger+0x7c:  movb    $0,0xbdaf09(%rip)
db>