panic: bpf_mcopy
Stopped at      db_enter+0xa:   popq    %rbp
    TID    PID    UID     PRFLAGS     PFLAGS  CPU  COMMAND
* 29463  54073      0         0x2          0    0  syz-executor0
db_enter() at db_enter+0xa
panic() at panic+0x147
bpf_mcopy(0,1,42) at bpf_mcopy+0x7f
ffff800021161d60(ffff800000074340,1,ffff800000074340,ffffff00068c5e00,ffff800021161c78,78b6a6cdc7f5e535) at 0xffff800021161d60
bpf_mtap_ether(ffff800021161cf8,42,ffff800000074340) at bpf_mtap_ether+0xeb
ifiq_input(ffff800000171050,ffff800000171290,ffffff00068c5e00) at ifiq_input+0x105
vio_rxeof(ffff800000171050) at vio_rxeof+0x220
vio_rx_intr(ffffffff) at vio_rx_intr+0x23
virtio_check_vqs(ffff80000001c300) at virtio_check_vqs+0x166
intr_handler(0,ffff80000024b980) at intr_handler+0x3f
Xintr_ioapic_edge19_untramp(0,20,5050d6b9000,0,20,ffff800021162150) at Xintr_ioapic_edge19_untramp+0x19f
copyout(ffff800021162150,ffff80000292e000,1,ffff80000292e008,20,ffff800021161f78) at copyout+0x5c
ufs_readdir(ffffffff81dfb828) at ufs_readdir+0x28d
VOP_READDIR(ffffff006e47b530,ffff8000210c39d8,ffff8000211621f0,10000) at VOP_READDIR+0x65
--db_more--           end trace frame: 0xffff8000211621b0, count: 0
--db_more--           https://www.openbsd.org/ddb.html describes the minimum info required in bug
--db_more--           reports.  Insufficient info makes it difficult to find and fix bugs.
ddb> t $lines = 0