panic: Assertion in_epoch(net_epoch_preempt) failed at /syzkaller/managers/main/kernel/sys/netinet/in_mcast.c:1319
cpuid = 0
time = 1570625303
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe0022b4b4b0
vpanic() at vpanic+0x1e0/frame 0xfffffe0022b4b510
panic() at panic+0x43/frame 0xfffffe0022b4b570
in_leavegroup_locked() at in_leavegroup_locked+0x215/frame 0xfffffe0022b4b5d0
inp_setmoptions() at inp_setmoptions+0x1290/frame 0xfffffe0022b4b7a0
ip_ctloutput() at ip_ctloutput+0x823/frame 0xfffffe0022b4b800
udp_ctloutput() at udp_ctloutput+0x171/frame 0xfffffe0022b4b850
sosetopt() at sosetopt+0x101/frame 0xfffffe0022b4b8d0
kern_setsockopt() at kern_setsockopt+0x14f/frame 0xfffffe0022b4b950
sys_setsockopt() at sys_setsockopt+0x33/frame 0xfffffe0022b4b980
amd64_syscall() at amd64_syscall+0x477/frame 0xfffffe0022b4bab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0022b4bab0
--- syscall (198, FreeBSD ELF64, nosys), rip = 0x4132aa, rsp = 0x7fffdfffdf38, rbp = 0x5 ---
KDB: enter: panic
[ thread pid 10014 tid 100134 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why