panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/main/kernel/sys/netinet/if_ether.c", line 716
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
* 47772  72692      0     0x14000 0x40000200    0  softclock
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic() at panic+0x15c sys/kern/subr_prf.c:207
__assert(ffffffff821e5fef,ffffffff822002b3,2cc,ffffffff8216f23d) at __assert+0x2b sys/kern/subr_prf.c:154
arptfree(fffffd803bc42af8) at arptfree+0xfb sys/netinet/if_ether.c:716
arptimer(ffffffff825251f0) at arptimer+0x95 sys/netinet/if_ether.c:120
softclock_thread(ffff8000ffffe768) at softclock_thread+0x145 timeout_run sys/kern/kern_timeout.c:475 [inline]
softclock_thread(ffff8000ffffe768) at softclock_thread+0x145 sys/kern/kern_timeout.c:552
end trace frame: 0x0, count: 9
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