syzbot

panic: Assertion in_epoch(net_epoch_preempt) failed at /syzkaller/managers/main/kernel/sys/net/if.c:3694
cpuid = 1
time = 1570552998
KDB: stack backtrace:
db_trace_self_wrapper() at db_trace_self_wrapper+0x47/frame 0xfffffe001a110850
vpanic() at vpanic+0x1e0/frame 0xfffffe001a1108b0
panic() at panic+0x43/frame 0xfffffe001a110910
if_delmulti_ifma_flags() at if_delmulti_ifma_flags+0x1af/frame 0xfffffe001a110950
inm_release_task() at inm_release_task+0x345/frame 0xfffffe001a1109c0
gtaskqueue_run_locked() at gtaskqueue_run_locked+0x13e/frame 0xfffffe001a110a20
gtaskqueue_thread_loop() at gtaskqueue_thread_loop+0xdd/frame 0xfffffe001a110a60
fork_exit() at fork_exit+0xb0/frame 0xfffffe001a110ab0
fork_trampoline() at fork_trampoline+0xe/frame 0xfffffe001a110ab0
--- trap 0, rip = 0, rsp = 0, rbp = 0 ---
KDB: enter: panic
[ thread pid 0 tid 100005 ]
Stopped at      kdb_enter+0x6a: movq    $0,kdb_why
db>