panic: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 776 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *522500 31348 0 0x14000 0x40000200 0K softclock db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff825abdbc) at panic+0x177 sys/kern/subr_prf.c:198 __assert(ffffffff82622021,ffffffff8261ee12,308,ffffffff8257920c) at __assert+0x25 sys/kern/subr_prf.c:157 arptfree(fffffd8064a6d408) at arptfree+0x12e sys/netinet/if_ether.c:776 arptimer(ffffffff82ae74a0) at arptimer+0x88 sys/netinet/if_ether.c:135 timeout_run(ffffffff82ae74a0) at timeout_run+0xcc sys/kern/kern_timeout.c:641 softclock_thread(ffff8000211e8fc0) at softclock_thread+0x134 sys/kern/kern_timeout.c:765 end trace frame: 0x0, count: 8 https://www.openbsd.org/ddb.html describes the minimum info required in bug reports. Insufficient info makes it difficult to find and fix bugs. ddb{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic *cpu0: kernel diagnostic assertion "ifp != NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/netinet/if_ether.c", line 776 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff825abdbc) at panic+0x177 sys/kern/subr_prf.c:198 __assert(ffffffff82622021,ffffffff8261ee12,308,ffffffff8257920c) at __assert+0x25 sys/kern/subr_prf.c:157 arptfree(fffffd8064a6d408) at arptfree+0x12e sys/netinet/if_ether.c:776 arptimer(ffffffff82ae74a0) at arptimer+0x88 sys/netinet/if_ether.c:135 timeout_run(ffffffff82ae74a0) at timeout_run+0xcc sys/kern/kern_timeout.c:641 softclock_thread(ffff8000211e8fc0) at softclock_thread+0x134 sys/kern/kern_timeout.c:765 end trace frame: 0x0, count: -7 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000211f5c40 rbx 0xffffffff8294ab8f cpu_info_full_primary+0x2b8f rdx 0 rcx 0 rax 0xffff8000211e8fc0 r8 0x101010101010101 r9 0x8080808080808080 r10 0xc02ae9dd16aade72 r11 0xa88595c7d1f22fd7 r12 0xffffffff8294a990 cpu_info_full_primary+0x2990 r13 0 r14 0 r15 0x1 rip 0xffffffff81176258 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000211f5c30 ss 0 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (softclock) pid=522500 stat=onproc flags process=14000 proc=40000200 pri=0, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff8000211e97a0,0xffff8000211e8d30 process=0xffff8000ffffcc90 user=0xffff8000211f0000, vmspace=0xffffffff82afb910 estcpu=0, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 29499 331623 1135 0 2 0 syz-executor.1 64486 486782 17041 0 2 0 syz-executor.2 64486 474397 17041 0 3 0x4000080 fsleep syz-executor.2 85551 331459 97721 0 2 0 syz-executor.4 85551 372375 97721 0 3 0x4000080 fsleep syz-executor.4 14016 508877 75484 0 2 0 syz-executor.5 14016 451253 75484 0 3 0x4000080 fsleep syz-executor.5 70389 44493 99039 0 3 0x80 nanoslp syz-executor.0 70389 182817 99039 0 3 0x4000080 fsleep syz-executor.0 97540 126272 43787 0 3 0x80 nanoslp syz-executor.7 97540 49886 43787 0 3 0x4000080 ttyin syz-executor.7 97540 337520 43787 0 3 0x4000080 fsleep syz-executor.7 97540 268841 43787 0 3 0x4000080 fsleep syz-executor.7 1135 416259 89295 0 3 0x82 nanoslp syz-executor.1 44370 376998 0 0 3 0x14200 acct acct 7680 487394 1 0 3 0x100083 ttyin getty 97721 491757 89295 0 3 0x82 nanoslp syz-executor.4 72696 269894 0 0 3 0x14280 nfsidl nfsio 59120 252364 0 0 3 0x14280 nfsidl nfsio 40108 426436 0 0 3 0x14280 nfsidl nfsio 10161 264831 0 0 3 0x14280 nfsidl nfsio 90034 371677 0 0 3 0x14280 nfsidl nfsio 81099 81347 0 0 3 0x14280 nfsidl nfsio 64468 476297 0 0 3 0x14280 nfsidl nfsio 3654 283392 0 0 3 0x14280 nfsidl nfsio 90652 91021 0 0 3 0x14280 nfsidl nfsio 43315 43700 0 0 3 0x14280 nfsidl nfsio 13074 114270 0 0 3 0x14280 nfsidl nfsio 44820 223530 0 0 3 0x14280 nfsidl nfsio 94193 106694 0 0 3 0x14280 nfsidl nfsio 28362 321778 0 0 3 0x14280 nfsidl nfsio 23268 104558 0 0 3 0x14280 nfsidl nfsio 9733 451733 0 0 3 0x14280 nfsidl nfsio 77391 71524 0 0 3 0x14280 nfsidl nfsio 98853 433338 0 0 3 0x14280 nfsidl nfsio 98237 356573 0 0 3 0x14280 nfsidl nfsio 71305 108384 0 0 3 0x14280 nfsidl nfsio 78032 197353 0 0 3 0x14200 bored sosplice 47237 422471 89295 0 2 0x2 syz-executor.6 43787 263169 89295 0 3 0x82 nanoslp syz-executor.7 75484 92091 89295 0 3 0x82 nanoslp syz-executor.5 17041 47685 89295 0 3 0x82 nanoslp syz-executor.2 99039 39980 89295 0 3 0x82 nanoslp syz-executor.0 89295 129778 97945 0 3 0x82 thrsleep syz-fuzzer 89295 478802 97945 0 2 0x4000482 syz-fuzzer 89295 33212 97945 0 3 0x4000082 wait syz-fuzzer 89295 296647 97945 0 3 0x4000082 thrsleep syz-fuzzer 89295 156202 97945 0 3 0x4000082 kqread syz-fuzzer 89295 343193 97945 0 3 0x4000082 wait syz-fuzzer 89295 317524 97945 0 3 0x4000082 wait syz-fuzzer 89295 383972 97945 0 3 0x4000082 wait syz-fuzzer 89295 336111 97945 0 3 0x4000082 thrsleep syz-fuzzer 89295 504009 97945 0 3 0x4000082 wait syz-fuzzer 89295 476451 97945 0 3 0x4000082 thrsleep syz-fuzzer 89295 143570 97945 0 3 0x4000082 wait syz-fuzzer 89295 310494 97945 0 3 0x4000082 wait syz-fuzzer 89295 159087 97945 0 3 0x4000082 wait syz-fuzzer 89295 224415 97945 0 3 0x4000082 thrsleep syz-fuzzer 89295 434243 97945 0 3 0x4000082 thrsleep syz-fuzzer 97945 219676 46355 0 3 0x10008a sigsusp ksh 46355 70809 99955 0 3 0x9a kqread sshd 99955 1853 1 0 3 0x88 kqread sshd 53774 231240 48996 74 3 0x1100092 bpf pflogd 48996 406460 1 0 3 0x80 netio pflogd 81146 464167 39864 73 3 0x1100090 kqread syslogd 39864 87335 1 0 3 0x100082 netio syslogd 62406 415950 1 0 3 0x100080 kqread resolvd 49251 430156 43521 77 3 0x100092 kqread dhcpleased 9483 440213 43521 77 3 0x100092 kqread dhcpleased 43521 151477 1 0 3 0x80 kqread dhcpleased 14057 233083 0 0 3 0x14200 bored smr 21220 133929 0 0 2 0x14200 zerothread 87220 474258 0 0 3 0x14200 aiodoned aiodoned 21049 204418 0 0 3 0x14200 syncer update 62233 258293 0 0 3 0x14200 cleaner cleaner 30108 225165 0 0 3 0x14200 reaper reaper 35258 381251 0 0 3 0x14200 pgdaemon pagedaemon 45843 82920 0 0 3 0x14200 bored viomb 74056 306598 0 0 3 0x40014200 acpi0 acpi0 81424 107663 0 0 7 0x40014200 idle1 54594 408556 0 0 3 0x14200 bored softnet 1619 424685 0 0 3 0x14200 bored softnet 36133 507554 0 0 3 0x14200 bored softnet 29415 172642 0 0 3 0x14200 bored softnet 92349 289848 0 0 2 0x14200 systqmp 70851 55216 0 0 3 0x14200 bored systq *31348 522500 0 0 7 0x40014200 softclock 7548 385430 0 0 3 0x40014200 idle0 1 390396 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 31348 (softclock) thread 0xffff8000211e8fc0 (522500) exclusive rwlock netlock r = 0 (0xffffffff829e0470) #0 witness_lock+0x44d #1 arptimer+0x22 sys/netinet/if_ether.c:132 #2 timeout_run+0xcc sys/kern/kern_timeout.c:641 #3 softclock_thread+0x134 sys/kern/kern_timeout.c:765 #4 proc_trampoline+0x1c shared rwlock timeout r = 0 (0xffffffff829553c8) #0 witness_lock+0x44d #1 timeout_run+0xb7 sys/kern/kern_timeout.c:637 #2 softclock_thread+0x134 sys/kern/kern_timeout.c:765 #3 proc_trampoline+0x1c exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82ae88d8) #0 witness_lock+0x44d #1 __mp_acquire_count+0x48 sys/kern/kern_lock.c:227 #2 mi_switch+0x3bb sys/kern/sched_bsd.c:415 #3 sleep_finish+0x180 sys/kern/kern_synch.c:417 #4 softclock_thread+0xd9 sys/kern/kern_timeout.c:760 #5 proc_trampoline+0x1c ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10234 6687K 7087K 78643K 17622 0 pcb 13 16K 18K 78643K 1175 0 rtable 193 15K 16K 78643K 789 0 ifaddr 68 16K 19K 78643K 249 0 sysctl 2 0K 0K 78643K 2 0 counters 56 35K 36K 78643K 152 0 ioctlops 0 0K 4K 78643K 2332 0 iov 0 0K 24K 78643K 229 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1697 106K 106K 78643K 5057 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 9K 78643K 48 0 VM map 2 1K 1K 78643K 2 0 sem 10 0K 0K 78643K 10 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 16 57K 89K 78643K 3019 0 sigio 0 0K 0K 78643K 84 0 proc 70 91K 115K 78643K 841 0 subproc 104 6K 6K 78643K 182 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 172 0 in_multi 73 4K 7K 78643K 290 0 ether_multi 1 0K 0K 78643K 28 0 mrt 1 0K 0K 78643K 18 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 163 731K 731K 78643K 163 0 exec 0 0K 1K 78643K 1202 0 tdb 3 0K 0K 78643K 3 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 8 62K 64K 78643K 10 0 UVM amap 402 326K 326K 78643K 21800 0 UVM aobj 131 4K 4K 78643K 143 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 139 0 NDP 11 0K 1K 78643K 84 0 temp 129 4698K 5722K 78643K 31509 0 kqueue 12 18K 28K 78643K 316 0 SYN cache 2 20K 28K 78643K 3 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 22 0 0 1 0 1 1 0 8 0 rtpcb 120 216 0 213 2 0 2 2 0 8 1 rtentry 112 235 0 152 4 0 4 4 0 8 0 unpcb 144 3461 0 3446 40 39 1 6 0 8 0 syncache 296 34 0 34 7 7 0 1 0 8 0 tcpqe 32 42 0 42 4 4 0 1 0 8 0 tcpcb 776 764 0 758 19 18 1 8 0 8 0 arp 120 33 0 20 1 0 1 1 0 8 0 inpcb 368 3538 0 3529 76 68 8 16 0 8 6 nd6 48 52 0 35 1 0 1 1 0 8 0 pkpcb 40 8 0 8 2 2 0 1 0 8 0 kcovpl 48 14 0 6 1 0 1 1 0 8 0 ppxss 1256 24 0 24 4 3 1 1 0 8 1 pppxif 1448 8 0 8 1 1 0 1 0 8 0 pffrag 232 11 0 9 2 1 1 1 0 482 0 pffrnode 88 11 0 9 2 1 1 1 0 8 0 pffrent 40 19 0 17 2 1 1 1 0 8 0 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfanchor 1280 854 0 410 46 4 42 42 0 8 1 pfstitem 24 42 0 40 1 0 1 1 0 8 0 pfstkey 120 42 0 40 1 0 1 1 0 8 0 pfstate 384 42 0 40 3 2 1 3 0 8 0 pfrule 1344 21 0 20 2 1 1 2 0 8 0 rttmr 136 3 0 3 1 1 0 1 0 8 0 art_heap8 4096 3 0 2 3 1 2 2 0 8 1 art_heap4 256 987 0 629 29 3 26 29 0 8 0 art_table 32 990 0 631 4 0 4 4 0 8 0 art_node 16 233 0 156 1 0 1 1 0 8 0 sysvmsgpl 40 13 0 3 1 0 1 1 0 8 0 semupl 112 8 0 8 3 3 0 1 0 8 0 semapl 112 8 0 0 1 0 1 1 0 8 0 shmpl 112 140 0 12 5 1 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 5492 0 4049 91 0 91 91 0 8 0 ffsino 272 5492 0 4049 97 0 97 97 0 8 0 nchpl 144 9756 0 8108 63 0 63 63 0 8 0 uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0 vnodes 216 5926 0 0 330 0 330 330 0 8 0 namei 1024 41120 0 41120 5 4 1 2 0 8 1 percpumem 16 88 0 48 1 0 1 1 0 8 0 vcpupl 2048 24 0 0 3 0 3 3 0 8 0 vmpool 568 30 0 6 2 0 2 2 0 8 0 kstatmem 264 98 0 76 2 0 2 2 0 8 0 scsiplug 72 6 0 6 2 2 0 1 0 8 0 scxspl 216 34765 0 34765 11 10 1 8 0 8 1 plimitpl 152 510 0 494 1 0 1 1 0 8 0 sigapl 424 3347 0 3279 10 2 8 8 0 8 0 futexpl 64 33820 0 33814 5 4 1 1 0 8 0 knotepl 120 479 0 0 10 0 10 10 0 8 0 kqueuepl 216 1049 0 1041 23 22 1 5 0 8 0 pipepl 320 659 0 631 17 14 3 9 0 8 0 fdescpl 496 3308 0 3279 5 1 4 5 0 8 0 filepl 152 28507 0 28247 74 59 15 21 0 8 5 lockfpl 104 708 0 706 3 1 2 2 0 8 1 lockfspl 48 278 0 276 1 0 1 1 0 8 0 sessionpl 144 32 0 15 1 0 1 1 0 8 0 pgrppl 48 43 0 26 1 0 1 1 0 8 0 ucredpl 104 3282 0 3270 1 0 1 1 0 8 0 zombiepl 144 3280 0 3279 1 0 1 1 0 8 0 processpl 1072 3347 0 3279 5 0 5 5 0 8 0 procpl 672 8177 0 8087 12 3 9 9 0 8 1 srpgc 96 18 0 18 2 2 0 1 0 8 0 sosppl 168 35 0 35 4 3 1 1 0 8 1 sockpl 488 7229 0 7202 194 182 12 28 0 8 8 mcl64k 65536 7 0 0 1 0 1 1 0 8 0 mcl16k 16384 4 0 0 1 0 1 1 0 8 0 mcl12k 12288 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 5 0 0 1 0 1 1 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 440 0 0 54 8 46 54 0 8 0 mtagpl 96 465 0 0 11 0 11 11 0 8 0 mbufpl 256 1436 0 0 84 1 83 83 0 8 0 bufpl 288 9316 0 2984 453 0 453 453 0 8 0 anonpl 24 751670 0 732015 204 59 145 146 0 186 19 amapchunkpl 152 61724 0 60880 57 22 35 42 0 158 1 amappl16 200 10624 0 10023 98 54 44 47 0 8 11 amappl15 192 7 0 7 2 1 1 1 0 8 1 amappl14 184 163 0 150 2 1 1 2 0 8 0 amappl13 176 4 0 4 1 1 0 1 0 8 0 amappl12 168 507 0 503 1 0 1 1 0 8 0 amappl11 160 61 0 46 1 0 1 1 0 8 0 amappl10 152 50 0 38 1 0 1 1 0 8 0 amappl9 144 977 0 975 1 0 1 1 0 8 0 amappl8 136 255 0 174 3 0 3 3 0 8 0 amappl7 128 169 0 144 2 1 1 2 0 8 0 amappl6 120 222 0 207 1 0 1 1 0 8 0 amappl5 112 212 0 202 1 0 1 1 0 8 0 amappl4 104 595 0 561 3 2 1 3 0 8 0 amappl3 96 9214 0 9161 2 0 2 2 0 8 0 amappl2 88 3841 0 3761 3 1 2 3 0 8 0 amappl1 80 77617 0 76826 23 5 18 23 0 8 0 amappl 88 21091 0 20876 7 1 6 6 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 253 0 253 1 1 0 1 0 8 0 dma64 64 6 0 6 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 142 0 12 3 0 3 3 0 8 0 uaddrrnd 24 3339 0 3286 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3339 0 3286 1 0 1 1 0 8 0 vmmpekpl 168 26784 0 26707 4 0 4 4 0 8 0 vmmpepl 168 311015 0 308034 217 73 144 157 0 357 4 vmsppl 368 3338 0 3286 6 1 5 5 0 8 0 rwobjpl 56 91505 0 83597 122 6 116 116 0 8 2 pdppl 4096 6685 0 6596 273 180 93 93 0 8 4 pvpl 32 1506711 0 1482184 365 127 238 274 0 265 26 pmappl 248 3338 0 3286 8 4 4 4 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 1188 0 271 27 0 27 27 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff825abdbc) at panic+0x177 sys/kern/subr_prf.c:198 __assert(ffffffff82622021,ffffffff8261ee12,308,ffffffff8257920c) at __assert+0x25 sys/kern/subr_prf.c:157 arptfree(fffffd8064a6d408) at arptfree+0x12e sys/netinet/if_ether.c:776 arptimer(ffffffff82ae74a0) at arptimer+0x88 sys/netinet/if_ether.c:135 timeout_run(ffffffff82ae74a0) at timeout_run+0xcc sys/kern/kern_timeout.c:641 softclock_thread(ffff8000211e8fc0) at softclock_thread+0x134 sys/kern/kern_timeout.c:765 end trace frame: 0x0, count: -7 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 acpicpu_idle() at acpicpu_idle+0x312 sys/dev/acpi/acpicpu.c:1206 sched_idle(ffff800020dd8ff0) at sched_idle+0x417 sys/kern/kern_sched.c:175 end trace frame: 0x0, count: 10 ddb{1}> trace x86_ipi_db(ffff800020dd8ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:393 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 acpicpu_idle() at acpicpu_idle+0x312 sys/dev/acpi/acpicpu.c:1206 sched_idle(ffff800020dd8ff0) at sched_idle+0x417 sys/kern/kern_sched.c:175 end trace frame: 0x0, count: -5