panic: Data modified on freelist: word 4 of object 0xffff800000c01200 size 0x120 previous type counters (0x6563 != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *430001 29184 0 0 0x4000000 0 syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8256a765) at panic+0x161 sys/kern/subr_prf.c:202 malloc(120,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:363 bpfopen(21700,1,2000,ffff800026720008) at bpfopen+0xb0 sys/net/bpf.c:387 spec_open_clone(ffff800027f91418) at spec_open_clone+0x204 spec_open(ffff800027f91418) at spec_open+0x3f5 sys/kern/spec_vnops.c:155 VOP_OPEN(fffffd8071ada9d8,1,fffffd807f7d7540,ffff800026720008) at VOP_OPEN+0x6c sys/kern/vfs_vops.c:138 vn_open(ffff800027f91668,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:183 doopenat(ffff800026720008,ffffff9c,20000240,0,0,ffff800027f91850) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800027f918c0) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x5785db689b0, count: 4 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> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic *cpu0: Data modified on freelist: word 4 of object 0xffff800000c01200 size 0x120 previous type counters (0x6563 != 0xdeafbead) ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8256a765) at panic+0x161 sys/kern/subr_prf.c:202 malloc(120,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:363 bpfopen(21700,1,2000,ffff800026720008) at bpfopen+0xb0 sys/net/bpf.c:387 spec_open_clone(ffff800027f91418) at spec_open_clone+0x204 spec_open(ffff800027f91418) at spec_open+0x3f5 sys/kern/spec_vnops.c:155 VOP_OPEN(fffffd8071ada9d8,1,fffffd807f7d7540,ffff800026720008) at VOP_OPEN+0x6c sys/kern/vfs_vops.c:138 vn_open(ffff800027f91668,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:183 doopenat(ffff800026720008,ffffff9c,20000240,0,0,ffff800027f91850) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800027f918c0) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x5785db689b0, count: -11 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff800027f91130 rbx 0xffff800000c01200 rdx 0xffff800000baf900 rcx 0 rax 0xffff800026720008 r8 0x101010101010101 r9 0x8080808080808080 r10 0xccec714f51190c8c r11 0xa4970cc3ae077d52 r12 0 r13 0x51 r14 0 r15 0x1 rip 0xffffffff81ae79e8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800027f91120 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.0) pid=430001 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=80, nice=20 forw=0xffffffffffffffff, list=0xffff800026721a48,0xffffffff82ab4698 process=0xffff80002160e028 user=0xffff800027f8c000, vmspace=0xfffffd806894e660 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 29184 403290 86328 0 2 0 syz-executor.0 *29184 430001 86328 0 7 0x4000000 syz-executor.0 3755 235036 28310 0 2 0 syz-executor.7 3755 480670 28310 0 3 0x4000080 fsleep syz-executor.7 88897 236109 26058 0 2 0 syz-executor.1 88897 427146 26058 0 3 0x4000080 fsleep syz-executor.1 88897 10543 26058 0 3 0x4000080 fsleep syz-executor.1 86328 61803 38896 0 3 0x82 nanoslp syz-executor.0 35231 95942 0 0 3 0x14200 acct acct 8513 436631 38896 0 2 0x2 syz-executor.6 28310 382687 38896 0 3 0x82 nanoslp syz-executor.7 73554 428795 38896 0 3 0x82 nanoslp syz-executor.3 43603 86318 0 0 3 0x14280 nfsidl nfsio 98136 295663 0 0 3 0x14280 nfsidl nfsio 30231 1223 0 0 3 0x14280 nfsidl nfsio 8029 354582 0 0 3 0x14280 nfsidl nfsio 26126 499247 0 0 3 0x14280 nfsidl nfsio 92855 507789 0 0 3 0x14280 nfsidl nfsio 5416 261404 0 0 3 0x14280 nfsidl nfsio 90559 199128 0 0 3 0x14280 nfsidl nfsio 31795 69451 0 0 3 0x14280 nfsidl nfsio 25721 388146 0 0 3 0x14280 nfsidl nfsio 3953 292976 0 0 3 0x14280 nfsidl nfsio 99097 4707 0 0 3 0x14280 nfsidl nfsio 62592 287286 0 0 3 0x14280 nfsidl nfsio 77082 218964 0 0 3 0x14280 nfsidl nfsio 48646 255443 0 0 3 0x14280 nfsidl nfsio 52118 164478 0 0 3 0x14280 nfsidl nfsio 10443 91011 0 0 3 0x14280 nfsidl nfsio 14792 34540 0 0 3 0x14280 nfsidl nfsio 7401 203585 0 0 3 0x14280 nfsidl nfsio 10529 231921 0 0 3 0x14280 nfsidl nfsio 6297 430499 38896 0 3 0x82 nanoslp syz-executor.5 26058 379454 38896 0 3 0x82 nanoslp syz-executor.1 89658 391162 38896 0 2 0x2 syz-executor.2 83071 88233 0 0 3 0x14200 bored sosplice 13766 323828 38896 0 3 0x82 piperd syz-executor.4 38896 298026 67610 0 3 0x82 thrsleep syz-fuzzer 38896 244499 67610 0 3 0x4000082 nanoslp syz-fuzzer 38896 6746 67610 0 3 0x4000082 thrsleep syz-fuzzer 38896 210384 67610 0 3 0x4000082 kqread syz-fuzzer 38896 301829 67610 0 3 0x4000082 thrsleep syz-fuzzer 38896 266504 67610 0 3 0x4000082 thrsleep syz-fuzzer 38896 420809 67610 0 3 0x4000082 thrsleep syz-fuzzer 38896 151331 67610 0 3 0x4000082 thrsleep syz-fuzzer 38896 336521 67610 0 3 0x4000082 thrsleep syz-fuzzer 67610 255923 22827 0 3 0x10008a sigsusp ksh 22827 237672 44177 0 3 0x9a kqread sshd 53483 240031 1 0 3 0x100083 ttyin getty 44177 106824 1 0 3 0x88 kqread sshd 68271 410294 66348 73 3 0x1100090 kqread syslogd 66348 470192 1 0 3 0x100082 netio syslogd 14120 365887 1 0 3 0x100080 kqread resolvd 46188 203363 15892 77 3 0x100092 kqread dhcpleased 49626 516754 15892 77 3 0x100092 kqread dhcpleased 15892 241301 1 0 3 0x80 kqread dhcpleased 22532 387533 0 0 3 0x14200 bored smr 72452 376519 0 0 2 0x14200 zerothread 95994 378644 0 0 3 0x14200 aiodoned aiodoned 75472 262922 0 0 3 0x14200 syncer update 15851 348514 0 0 3 0x14200 cleaner cleaner 55909 202692 0 0 3 0x14200 reaper reaper 4382 329794 0 0 3 0x14200 pgdaemon pagedaemon 98767 524164 0 0 3 0x14200 bored viomb 90024 277703 0 0 3 0x40014200 acpi0 acpi0 9904 52844 0 0 3 0x14200 bored softnet 62972 288525 0 0 3 0x14200 bored softnet 41707 377190 0 0 3 0x14200 bored softnet 34119 433849 0 0 3 0x14200 bored softnet 34424 25324 0 0 3 0x14200 bored systqmp 20532 49816 0 0 3 0x14200 bored systq 25087 148084 0 0 3 0x40014200 bored softclock 30629 467117 0 0 3 0x40014200 idle0 1 343220 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10197 6606K 7836K 78643K 26342 0 pcb 13 16K 18K 78643K 576 0 rtable 190 10K 13K 78643K 1479 0 ifaddr 87 17K 18K 78643K 439 0 sysctl 2 0K 0K 78643K 2 0 counters 27 17K 17K 78643K 72 0 ioctlops 0 0K 4K 78643K 894 0 iov 0 0K 32K 78643K 332 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1438 90K 90K 78643K 5484 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 20 0 VM map 2 0K 0K 78643K 2 0 sem 12 3K 5K 78643K 26 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 13 45K 85K 78643K 3742 0 sigio 0 0K 0K 78643K 11 0 proc 58 59K 83K 78643K 978 0 subproc 104 6K 7K 78643K 286 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 79 0 in_multi 81 5K 6K 78643K 293 0 ether_multi 1 0K 0K 78643K 10 0 mrt 1 0K 0K 78643K 9 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 85 387K 387K 78643K 85 0 exec 0 0K 2K 78643K 1563 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 7 26K 26K 78643K 7 0 UVM amap 299 360K 361K 78643K 21405 0 UVM aobj 98 7K 7K 78643K 113 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 102 0 NDP 13 0K 1K 78643K 105 0 temp 128 4748K 5757K 78643K 36827 0 kqueue 12 18K 26K 78643K 273 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 237 0 234 3 2 1 3 0 8 0 rtentry 112 429 0 347 4 0 4 4 0 8 0 unpcb 136 2045 0 2030 22 21 1 8 0 8 0 syncache 296 20 0 20 5 5 0 1 0 8 0 tcpqe 32 9 0 9 3 3 0 1 0 8 0 tcpcb 736 2798 0 2771 74 68 6 16 0 8 3 arp 88 91 0 77 1 0 1 1 0 8 0 inpcb 312 4741 0 4733 60 54 6 14 0 8 5 ip6q 72 3 0 3 1 1 0 1 0 8 0 ip6af 40 9 0 9 1 1 0 1 0 8 0 nd6 48 73 0 54 1 0 1 1 0 8 0 pkpcb 40 4 0 4 1 1 0 1 0 8 0 kcovpl 48 22 0 14 1 0 1 1 0 8 0 ppxss 1152 10 0 10 3 3 0 1 0 8 0 pfstscr 40 6 0 4 1 0 1 1 0 8 0 pfosfp 40 6 0 4 1 0 1 1 0 8 0 pfosfpen 112 6 0 0 1 0 1 1 0 8 0 pfrktable 1344 153 0 152 4 3 1 1 0 8 0 pftag 88 25 0 23 2 1 1 1 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 112 6 0 4 1 0 1 1 0 8 0 pfstate 336 3 0 2 1 0 1 1 0 8 0 pfrule 1360 106 0 88 2 0 2 2 0 8 0 rttmr 64 4 0 4 1 0 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 1329 0 962 36 13 23 30 0 8 0 art_table 32 1330 0 962 4 0 4 4 0 8 0 art_node 16 428 0 359 1 0 1 1 0 8 0 sysvmsgpl 40 95 0 95 3 3 0 1 0 8 0 semupl 112 8 0 8 1 1 0 1 0 8 0 semapl 112 10 0 0 1 0 1 1 0 8 0 shmpl 112 110 0 15 3 0 3 3 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 6430 0 4998 90 0 90 90 0 8 0 ffsino 240 6430 0 4998 85 0 85 85 0 8 0 nchpl 144 11512 0 9881 63 0 63 63 0 8 0 uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0 vnodes 224 5926 0 0 349 0 349 349 0 8 0 namei 1024 42517 0 42517 2 1 1 2 0 8 1 vcpupl 1984 92 0 2 12 0 12 12 0 8 0 vmpool 528 99 0 9 6 0 6 6 0 8 0 pfiaddrpl 120 44 0 44 5 5 0 1 0 8 0 kstatmem 264 116 0 90 2 0 2 2 0 8 0 scsiplug 72 3 0 3 1 1 0 1 0 8 0 scxspl 216 36143 0 36143 16 15 1 8 0 8 1 plimitpl 152 381 0 367 1 0 1 1 0 8 0 sigapl 424 4019 0 3955 8 0 8 8 0 8 0 futexpl 64 37138 0 37135 1 0 1 1 0 8 0 knotepl 120 43098 0 43018 20 16 4 11 0 8 0 kqueuepl 184 651 0 643 11 10 1 4 0 8 0 pipepl 304 793 0 765 12 9 3 8 0 8 0 fdescpl 432 3980 0 3956 4 0 4 4 0 8 0 filepl 120 28070 0 27827 45 35 10 18 0 8 2 lockfpl 104 677 0 675 2 1 1 2 0 8 0 lockfspl 48 232 0 230 1 0 1 1 0 8 0 sessionpl 144 37 0 21 1 0 1 1 0 8 0 pgrppl 48 116 0 100 1 0 1 1 0 8 0 ucredpl 96 3885 0 3874 1 0 1 1 0 8 0 zombiepl 144 3957 0 3955 1 0 1 1 0 8 0 processpl 1000 4019 0 3955 11 2 9 9 0 8 0 procpl 672 9529 0 9453 14 6 8 9 0 8 0 sosppl 168 27 0 27 6 6 0 1 0 8 0 sockpl 448 7030 0 7004 135 124 11 40 0 8 8 mcl64k 65536 129 0 129 8 7 1 1 0 8 1 mcl16k 16384 37 0 37 8 7 1 1 0 8 1 mcl12k 12288 141 0 141 5 4 1 1 0 8 1 mcl9k 9216 44 0 44 4 4 0 1 0 8 0 mcl8k 8192 224 0 224 5 4 1 1 0 8 1 mcl4k 4096 425 0 425 4 3 1 1 0 8 1 mcl2k2 2112 33 0 33 6 5 1 1 0 8 1 mcl2k 2048 75244 0 75193 15 7 8 11 0 8 0 mtagpl 96 384 0 320 6 4 2 3 0 8 0 mbufpl 256 143235 0 142938 38 15 23 27 0 8 1 bufpl 288 10280 0 3879 458 0 458 458 0 8 0 anonpl 24 808053 0 786555 246 90 156 156 0 188 5 amapchunkpl 152 67110 0 66479 54 26 28 37 0 158 1 amappl16 200 15322 0 14428 113 53 60 60 0 8 8 amappl15 192 1174 0 1169 1 0 1 1 0 8 0 amappl14 184 395 0 392 1 0 1 1 0 8 0 amappl13 176 321 0 320 1 0 1 1 0 8 0 amappl12 168 137 0 134 2 1 1 1 0 8 0 amappl11 160 239 0 222 1 0 1 1 0 8 0 amappl10 152 987 0 982 1 0 1 1 0 8 0 amappl9 144 1306 0 1299 1 0 1 1 0 8 0 amappl8 136 827 0 762 3 0 3 3 0 8 0 amappl7 128 164 0 154 1 0 1 1 0 8 0 amappl6 120 1105 0 1083 2 1 1 2 0 8 0 amappl5 112 4117 0 4101 1 0 1 1 0 8 0 amappl4 104 1556 0 1526 2 0 2 2 0 8 0 amappl3 96 10801 0 10761 2 0 2 2 0 8 0 amappl2 88 4694 0 4633 3 1 2 3 0 8 0 amappl1 80 93960 0 93387 21 6 15 19 0 8 0 amappl 88 20594 0 20431 6 1 5 5 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 72 112 0 15 2 0 2 2 0 8 0 uaddrrnd 24 4079 0 3965 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 4079 0 3965 1 0 1 1 0 8 0 vmmpekpl 168 31795 0 31730 4 0 4 4 0 8 0 vmmpepl 168 391009 0 388268 218 79 139 152 0 357 9 vmsppl 272 4078 0 3965 10 2 8 8 0 8 0 rwobjpl 24 102699 0 94825 50 0 50 50 0 8 0 pdppl 4096 8164 0 8020 314 160 154 154 0 8 10 pvpl 32 1646574 0 1622293 379 148 231 239 0 265 10 pmappl 216 4078 0 3965 7 0 7 7 0 8 0 extentpl 40 58 0 38 1 0 1 1 0 8 0 phpool 112 1352 0 467 26 0 26 26 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8256a765) at panic+0x161 sys/kern/subr_prf.c:202 malloc(120,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:363 bpfopen(21700,1,2000,ffff800026720008) at bpfopen+0xb0 sys/net/bpf.c:387 spec_open_clone(ffff800027f91418) at spec_open_clone+0x204 spec_open(ffff800027f91418) at spec_open+0x3f5 sys/kern/spec_vnops.c:155 VOP_OPEN(fffffd8071ada9d8,1,fffffd807f7d7540,ffff800026720008) at VOP_OPEN+0x6c sys/kern/vfs_vops.c:138 vn_open(ffff800027f91668,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:183 doopenat(ffff800026720008,ffffff9c,20000240,0,0,ffff800027f91850) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800027f918c0) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x5785db689b0, count: -11 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8256a765) at panic+0x161 sys/kern/subr_prf.c:202 malloc(120,2,a) at malloc+0xa85 sys/kern/kern_malloc.c:363 bpfopen(21700,1,2000,ffff800026720008) at bpfopen+0xb0 sys/net/bpf.c:387 spec_open_clone(ffff800027f91418) at spec_open_clone+0x204 spec_open(ffff800027f91418) at spec_open+0x3f5 sys/kern/spec_vnops.c:155 VOP_OPEN(fffffd8071ada9d8,1,fffffd807f7d7540,ffff800026720008) at VOP_OPEN+0x6c sys/kern/vfs_vops.c:138 vn_open(ffff800027f91668,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:183 doopenat(ffff800026720008,ffffff9c,20000240,0,0,ffff800027f91850) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800027f918c0) at syscall+0x44e sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x5785db689b0, count: -11