panic: mtx_lock() of spin mutex (null) @ /syzkaller/managers/main/kernel/sys/kern/sys_socket.c:811
cpuid = 0
time = 1558425188
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe001f886720
vpanic() at vpanic+0x1e0/frame 0xfffffe001f886780
panic() at panic+0x43/frame 0xfffffe001f8867e0
__mtx_lock_flags() at __mtx_lock_flags+0x1fd/frame 0xfffffe001f886840
soo_aio_queue() at soo_aio_queue+0xab/frame 0xfffffe001f886880
aio_aqueue() at aio_aqueue+0x75d/frame 0xfffffe001f886980
amd64_syscall() at amd64_syscall+0x436/frame 0xfffffe001f886ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe001f886ab0
--- syscall (255, FreeBSD ELF64, sys_aio_read), rip = 0x20000149, rsp = 0x7fffdfffded0, rbp = 0xa ---
KDB: enter: panic
[ thread pid 780 tid 100109 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why