panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/main/kernel/sys/netinet/if_ether.c", line 776
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
*185804  33080      0     0x14000 0x40000200    0  softclock
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff8272202f) at panic+0x161 sys/kern/subr_prf.c:198
__assert(ffffffff827a041e,ffffffff827c3a80,308,ffffffff826f39d6) at __assert+0x25 sys/kern/subr_prf.c:157
arptfree(fffffd806ed47d98) at arptfree+0x12d sys/netinet/if_ether.c:776
arptimer(ffffffff82c56c68) at arptimer+0x88 sys/netinet/if_ether.c:135
timeout_run(ffffffff82c56c68) at timeout_run+0x8b sys/kern/kern_timeout.c:641
softclock_thread(ffff8000fffff050) at softclock_thread+0xf4 sys/kern/kern_timeout.c:765
end trace frame: 0x0, count: 8
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