panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 716
Stopped at      db_enter+0x18:  addq    $0x8,%rsp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
 252781   3176      0     0x14000      0x200    1  systqmp
*374323  59664      0     0x14000 0x40000200    0K 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(ffffffff82206f14,ffffffff822036d8,2cc,ffffffff8218b97b) at __assert+0x2b sys/kern/subr_prf.c:154
arptfree(fffffd806501c4d8) at arptfree+0xfb sys/netinet/if_ether.c:716
arptimer(ffffffff82544d58) at arptimer+0x95 sys/netinet/if_ether.c:120
timeout_run(ffffffff82544d58) at timeout_run+0xc4 timeout_sync_leave sys/kern/kern_timeout.c:177 [inline]
timeout_run(ffffffff82544d58) at timeout_run+0xc4 sys/kern/kern_timeout.c:474
softclock_thread(ffff800020a10ed0) at softclock_thread+0x16a sys/kern/kern_timeout.c:553
end trace frame: 0x0, count: 8
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