panic: Assertion in_epoch(net_epoch_preempt) failed at /syzkaller/managers/main/kernel/sys/netinet/in_mcast.c:1319
cpuid = 0
time = 1570627736
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe00243824c0
vpanic() at vpanic+0x1e0/frame 0xfffffe0024382520
panic() at panic+0x43/frame 0xfffffe0024382580
in_leavegroup_locked() at in_leavegroup_locked+0x215/frame 0xfffffe00243825e0
inp_setmoptions() at inp_setmoptions+0x1290/frame 0xfffffe00243827b0
ip_ctloutput() at ip_ctloutput+0x823/frame 0xfffffe0024382810
rip_ctloutput() at rip_ctloutput+0x2c9/frame 0xfffffe0024382850
sosetopt() at sosetopt+0x101/frame 0xfffffe00243828d0
kern_setsockopt() at kern_setsockopt+0x14f/frame 0xfffffe0024382950
sys_setsockopt() at sys_setsockopt+0x33/frame 0xfffffe0024382980
amd64_syscall() at amd64_syscall+0x477/frame 0xfffffe0024382ab0
fast_syscall_common() at fast_syscall_common+0x101/frame 0xfffffe0024382ab0
--- syscall (198, FreeBSD ELF64, nosys), rip = 0x4132aa, rsp = 0x7fffdfffdf38, rbp = 0x5 ---
KDB: enter: panic
[ thread pid 1414 tid 100672 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why