panic: Data modified on freelist: word 4 of object 0xffff800001164600 size 0x200 previous type free (0x6563 != 0xdeadbeef) Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *123610 42209 0 0x8000000 0x4000000 0 syz-executor.4 db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff83009ef2) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(200,7f,1) at malloc+0xd7c sys/kern/kern_malloc.c:349 vndsetcred(ffff80002a543468,fffffd8070affd90,58,ffff80002a5c0c70) at vndsetcred+0x65 sys/dev/vnd.c:680 vndioctl(2902,c0384600,ffff80002a5c0ee0,1,ffff80002a543468) at vndioctl+0xe6c sys/dev/vnd.c:485 VOP_IOCTL(fffffd806e753de0,c0384600,ffff80002a5c0ee0,1,fffffd807f7d78f0,ffff80002a543468) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd80689df8e8,c0384600,ffff80002a5c0ee0,ffff80002a543468) at vn_ioctl+0xe8 sys/kern/vfs_vnops.c:525 sys_ioctl(ffff80002a543468,ffff80002a5c10c0,ffff80002a5c1010) at sys_ioctl+0x678 syscall(ffff80002a5c10c0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x90eb4647c10, count: 5 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 0xffff800001164600 size 0x200 previous type free (0x6563 != 0xdeadbeef) ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff83009ef2) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(200,7f,1) at malloc+0xd7c sys/kern/kern_malloc.c:349 vndsetcred(ffff80002a543468,fffffd8070affd90,58,ffff80002a5c0c70) at vndsetcred+0x65 sys/dev/vnd.c:680 vndioctl(2902,c0384600,ffff80002a5c0ee0,1,ffff80002a543468) at vndioctl+0xe6c sys/dev/vnd.c:485 VOP_IOCTL(fffffd806e753de0,c0384600,ffff80002a5c0ee0,1,fffffd807f7d78f0,ffff80002a543468) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd80689df8e8,c0384600,ffff80002a5c0ee0,ffff80002a543468) at vn_ioctl+0xe8 sys/kern/vfs_vnops.c:525 sys_ioctl(ffff80002a543468,ffff80002a5c10c0,ffff80002a5c1010) at sys_ioctl+0x678 syscall(ffff80002a5c10c0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x90eb4647c10, count: -10 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002a5c04c0 rbx 0xffff800001164600 rdx 0x3fd rcx 0 rax 0x7c r8 0x101010101010101 r9 0x8080808080808080 r10 0x909288dccdf0fb3b r11 0x75359277c58b51ec r12 0 r13 0xffffffff834b9438 bucket+0x288 r14 0 r15 0x1 rip 0xffffffff82cffde5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80002a5c04b0 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb> show proc PROC (syz-executor.4) tid=123610 pid=42209 tcnt=2 stat=onproc flags process=8000000 proc=4000000 runpri=32, usrpri=86, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80002a543978,0xffffffff835e2bc0 process=0xffff80002a630a98 user=0xffff80002a5bc000, vmspace=0xfffffd8069562570 estcpu=36, cpticks=2, pctcpu=0.0, user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 42209 416259 35488 0 2 0x8000000 syz-executor.4 *42209 123610 35488 0 7 0xc000000 syz-executor.4 32885 12510 31517 0 2 0x8000000 syz-executor.3 32885 310041 31517 0 2 0xc000000 syz-executor.3 67702 521015 33795 0 2 0x8000000 syz-executor.7 67702 381253 33795 0 3 0xc000080 fsleep syz-executor.7 925 403000 43993 0 2 0x8000002 syz-executor.6 35488 428459 43993 0 3 0x8000082 nanoslp syz-executor.4 50325 340456 43993 0 2 0x8000002 syz-executor.5 33795 319299 43993 0 3 0x8000082 nanoslp syz-executor.7 31517 420708 43993 0 3 0x8000082 nanoslp syz-executor.3 16009 199531 43993 0 2 0x8000002 syz-executor.2 83524 390541 43993 0 2 0x8000002 syz-executor.1 38616 148007 43993 0 2 0x8000002 syz-executor.0 43993 523270 73671 0 3 0x18000082 thrsleep syz-execprog 43993 174048 73671 0 3 0x1c000082 thrsleep syz-execprog 43993 116464 73671 0 3 0x1c000082 wait syz-execprog 43993 181615 73671 0 3 0x1c000082 thrsleep syz-execprog 43993 277020 73671 0 3 0x1c000082 wait syz-execprog 43993 510745 73671 0 3 0x1c000082 wait syz-execprog 43993 84952 73671 0 3 0x1c000082 wait syz-execprog 43993 192136 73671 0 3 0x1c000082 wait syz-execprog 43993 74999 73671 0 3 0x1c000082 wait syz-execprog 43993 384658 73671 0 3 0x1c000082 thrsleep syz-execprog 43993 61172 73671 0 3 0x1c000082 wait syz-execprog 43993 43681 73671 0 3 0x1c000082 wait syz-execprog 43993 344318 73671 0 3 0x1c000082 kqread syz-execprog 73671 273866 56503 0 3 0x810008a sigsusp ksh 56503 422221 91298 0 3 0x18000098 kqread sshd-session 91298 338357 2460 0 3 0x18000092 kqread sshd-session 65713 3422 1 0 3 0x18100083 ttyin getty 2460 165740 1 0 3 0x18000088 kqread sshd 16187 284799 56934 73 3 0x19100090 kqread syslogd 56934 274072 1 0 3 0x18100082 sbwait syslogd 60477 164982 1 0 3 0x18100080 kqread resolvd 88170 19815 3190 77 3 0x18100092 kqread dhcpleased 57454 522371 3190 77 3 0x18100092 kqread dhcpleased 3190 133879 1 0 3 0x18000080 kqread dhcpleased 46674 430522 0 0 3 0x14200 bored smr 45791 170809 0 0 2 0x14200 zerothread 30469 406683 0 0 3 0x14200 aiodoned aiodoned 28561 454364 0 0 3 0x14200 syncer update 32457 382608 0 0 3 0x14200 cleaner cleaner 25270 315489 0 0 3 0x14200 reaper reaper 23898 169143 0 0 3 0x14200 pgdaemon pagedaemon 85604 460440 0 0 3 0x14200 bored viomb 93546 512687 0 0 3 0x40014200 acpi0 acpi0 26418 115535 0 0 3 0x14200 bored softnet3 59795 173418 0 0 3 0x14200 bored softnet2 30134 154489 0 0 3 0x14200 bored softnet1 35272 261232 0 0 3 0x14200 bored softnet0 18678 374837 0 0 3 0x14200 bored systqmp 99153 312944 0 0 3 0x14200 bored systq 16081 187703 0 0 3 0x40014200 tmoslp softclock 50844 448532 0 0 3 0x40014200 idle0 1 2077 0 0 3 0x8000082 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 10162 10080K 10093K 166960K 11263 0 pcb 17 12K 12K 166960K 17 0 rtable 234 6K 6K 166960K 380 0 pf 30 12K 12K 166960K 33 0 ifaddr 42 7K 7K 166960K 48 0 ifgroup 50 2K 2K 166960K 55 0 counters 30 17K 17K 166960K 31 0 ioctlops 0 0K 2K 166960K 30 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1259 79K 79K 166960K 1276 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 1K 166960K 2 0 VM map 2 1K 1K 166960K 2 0 sem 2 0K 0K 166960K 2 0 dirhash 12 2K 2K 166960K 12 0 ACPI 1697 195K 286K 166960K 12548 0 file desc 13 45K 69K 166960K 187 0 proc 55 58K 75K 166960K 498 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 in_multi 99 7K 7K 166960K 110 0 ether_multi 1 0K 0K 166960K 1 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 25 122K 122K 166960K 25 0 exec 0 0K 1K 166960K 406 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 228 73K 74K 166960K 4492 0 UVM aobj 3 2K 2K 166960K 3 0 pinsyscall 35 70K 104K 166960K 1506 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 NDP 15 0K 2K 166960K 30 0 temp 1 6796K 6860K 166960K 4645 0 kqueue 13 20K 20K 166960K 46 0 SYN cache 2 16K 16K 166960K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 38 0 35 1 0 1 1 0 8 0 rtentry 112 122 0 12 4 0 4 4 0 8 0 unpcb 144 67 0 52 1 0 1 1 0 8 0 syncache 336 9 0 9 1 0 1 1 0 8 1 tcpcb 808 12 0 9 1 0 1 1 0 8 0 arp 88 20 0 2 1 0 1 1 0 8 0 inpcb 336 66 0 60 1 0 1 1 0 8 0 nd6 104 27 0 3 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 501 0 48 29 0 29 29 0 8 0 art_table 32 502 0 48 4 0 4 4 0 8 0 art_node 16 121 0 21 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1682 0 159 96 0 96 96 0 8 0 ffsino 240 1682 0 159 90 0 90 90 0 8 0 nchpl 144 2036 0 262 66 0 66 66 0 8 0 uvmvnodes 80 1692 0 0 35 0 35 35 0 8 0 vnodes 216 1692 0 0 94 0 94 94 0 8 0 namei 1024 7744 0 7744 2 0 2 2 0 8 2 kstatmem 264 24 0 2 2 0 2 2 0 8 0 scxspl 216 11309 0 11309 8 0 8 8 1 8 8 plimitpl 152 58 0 42 1 0 1 1 0 8 0 sigapl 424 526 0 485 6 0 6 6 0 8 0 futexpl 64 313 0 312 1 0 1 1 0 8 0 knotepl 120 6449 0 6370 3 0 3 3 0 8 0 kqueuepl 184 42 0 33 1 0 1 1 0 8 0 pipepl 288 183 0 155 3 0 3 3 0 8 1 fdescpl 432 510 0 485 4 0 4 4 0 8 0 filepl 120 2142 0 2005 5 0 5 5 0 8 0 lockfpl 104 6 0 4 1 0 1 1 0 8 0 lockfspl 48 4 0 2 1 0 1 1 0 8 0 sessionpl 144 34 0 18 1 0 1 1 0 8 0 pgrppl 48 34 0 18 1 0 1 1 0 8 0 ucredpl 104 132 0 120 1 0 1 1 0 8 0 zombiepl 144 485 0 485 1 0 1 1 0 8 1 processpl 1088 526 0 485 4 0 4 4 0 8 0 procpl 648 594 0 538 6 0 6 6 0 8 0 sockpl 504 171 0 147 4 0 4 4 0 8 0 mcl8k 8192 13 0 13 1 0 1 1 0 8 1 mcl4k 4096 9 0 9 1 0 1 1 0 8 1 mcl2k 2048 16830 0 16727 38 16 22 30 0 8 8 mtagpl 96 4 0 4 1 0 1 1 0 8 1 mbufpl 256 20718 0 20515 16 0 16 16 0 8 3 bufpl 280 6999 0 671 453 0 453 453 0 8 0 anonpl 24 327337 0 322430 55 0 55 55 0 187 21 amapchunkpl 152 16355 0 15857 27 0 27 27 0 158 5 amappl16 200 9615 0 9487 9 0 9 9 0 8 0 amappl15 192 16 0 16 1 0 1 1 0 8 1 amappl14 184 219 0 207 2 0 2 2 0 8 1 amappl13 176 51 0 49 1 0 1 1 0 8 0 amappl12 168 1209 0 1184 2 0 2 2 0 8 0 amappl11 160 66 0 56 1 0 1 1 0 8 0 amappl10 152 76 0 67 1 0 1 1 0 8 0 amappl9 144 346 0 345 1 0 1 1 0 8 0 amappl8 136 165 0 140 1 0 1 1 0 8 0 amappl7 128 206 0 192 2 0 2 2 0 8 0 amappl6 120 294 0 290 1 0 1 1 0 8 0 amappl5 112 251 0 242 1 0 1 1 0 8 0 amappl4 104 480 0 461 2 0 2 2 0 8 1 amappl3 96 4039 0 3968 3 0 3 3 0 8 1 amappl2 88 1151 0 1082 4 0 4 4 0 8 2 amappl1 80 15355 0 14811 26 7 19 23 0 8 7 amappl 88 3759 0 3613 4 0 4 4 0 92 0 dma4096 4096 1 0 1 1 0 1 1 0 8 1 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 0 1 1 0 8 1 dma128 128 253 0 253 1 0 1 1 0 8 1 dma64 64 6 0 6 1 0 1 1 0 8 1 dma32 32 7 0 7 1 0 1 1 0 8 1 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 510 0 485 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 510 0 485 1 0 1 1 0 8 0 vmmpekpl 168 12852 0 12818 2 0 2 2 0 8 0 vmmpepl 168 69947 0 68263 119 0 119 119 0 357 40 vmsppl 344 509 0 485 3 0 3 3 0 8 0 rwobjpl 24 32137 0 29479 20 0 20 20 0 8 1 pdppl 4096 1027 0 970 111 42 69 69 0 8 12 pvpl 32 676211 0 665918 398 100 298 398 0 265 208 pmappl 216 509 0 485 2 0 2 2 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 405 0 58 10 0 10 10 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff83009ef2) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(200,7f,1) at malloc+0xd7c sys/kern/kern_malloc.c:349 vndsetcred(ffff80002a543468,fffffd8070affd90,58,ffff80002a5c0c70) at vndsetcred+0x65 sys/dev/vnd.c:680 vndioctl(2902,c0384600,ffff80002a5c0ee0,1,ffff80002a543468) at vndioctl+0xe6c sys/dev/vnd.c:485 VOP_IOCTL(fffffd806e753de0,c0384600,ffff80002a5c0ee0,1,fffffd807f7d78f0,ffff80002a543468) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd80689df8e8,c0384600,ffff80002a5c0ee0,ffff80002a543468) at vn_ioctl+0xe8 sys/kern/vfs_vnops.c:525 sys_ioctl(ffff80002a543468,ffff80002a5c10c0,ffff80002a5c1010) at sys_ioctl+0x678 syscall(ffff80002a5c10c0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x90eb4647c10, count: -10 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff83009ef2) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(200,7f,1) at malloc+0xd7c sys/kern/kern_malloc.c:349 vndsetcred(ffff80002a543468,fffffd8070affd90,58,ffff80002a5c0c70) at vndsetcred+0x65 sys/dev/vnd.c:680 vndioctl(2902,c0384600,ffff80002a5c0ee0,1,ffff80002a543468) at vndioctl+0xe6c sys/dev/vnd.c:485 VOP_IOCTL(fffffd806e753de0,c0384600,ffff80002a5c0ee0,1,fffffd807f7d78f0,ffff80002a543468) at VOP_IOCTL+0xa3 sys/kern/vfs_vops.c:264 vn_ioctl(fffffd80689df8e8,c0384600,ffff80002a5c0ee0,ffff80002a543468) at vn_ioctl+0xe8 sys/kern/vfs_vnops.c:525 sys_ioctl(ffff80002a543468,ffff80002a5c10c0,ffff80002a5c1010) at sys_ioctl+0x678 syscall(ffff80002a5c10c0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x90eb4647c10, count: -10