panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 758
Stopped at      db_enter+0x1c:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 112388  80096      0         0x2          0    1  syz-executor.3
*450885  82912      0     0x14000 0x40000200    0K softclock
db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437
panic(ffffffff827a087c) at panic+0x17b sys/kern/subr_prf.c:198
__assert(ffffffff82821cfb,ffffffff8281c1fb,2f6,ffffffff8276e69b) at __assert+0x29 sys/kern/subr_prf.c:157
arptfree(fffffd8064c12248) at arptfree+0x132 sys/netinet/if_ether.c:758
arptimer(ffffffff82ca6ec0) at arptimer+0x88 sys/netinet/if_ether.c:135
timeout_run(ffffffff82ca6ec0) at timeout_run+0xd0 sys/kern/kern_timeout.c:640
softclock_thread(ffff800021168d48) at softclock_thread+0x124 sys/kern/kern_timeout.c:763
end trace frame: 0x0, count: 8
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