panic: Assertion in_epoch(net_epoch_preempt) failed at /syzkaller/managers/main/kernel/sys/net/if.c:3694 cpuid = 1 time = 1570550451 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>