panic: Data modified on freelist: word 4 of object 0xffff800000c955c0 size 0x38 previous type free (0x0 != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *215588 38873 0 0 0x4000000 0K syz-executor.5 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8259bb45) at panic+0x177 sys/kern/subr_prf.c:202 malloc(38,19,1) at malloc+0xa85 sys/kern/kern_malloc.c:363 checkalias(fffffd807bcfa010,31700,0) at checkalias+0x269 sys/kern/vfs_subr.c:586 cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 getdevvp sys/kern/vfs_subr.c:535 [inline] cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 sys/kern/vfs_subr.c:509 spec_open_clone(ffff800025db3e68) at spec_open_clone+0x193 sys/kern/spec_vnops.c:728 spec_open(ffff800025db3e68) at spec_open+0x3fd sys/kern/spec_vnops.c:153 VOP_OPEN(fffffd806f1f3390,1,fffffd807f7d74e0,ffff80002701ad30) at VOP_OPEN+0x75 sys/kern/vfs_vops.c:138 vn_open(ffff800025db40b8,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:180 doopenat(ffff80002701ad30,ffffff9c,20000000,0,0,ffff800025db4290) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800025db4310) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline] syscall(ffff800025db4310) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xe6a50e07c80, count: 3 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: Data modified on freelist: word 4 of object 0xffff800000c955c0 size 0x38 previous type free (0x0 != 0xdeafbead) ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff8259bb45) at panic+0x177 sys/kern/subr_prf.c:202 malloc(38,19,1) at malloc+0xa85 sys/kern/kern_malloc.c:363 checkalias(fffffd807bcfa010,31700,0) at checkalias+0x269 sys/kern/vfs_subr.c:586 cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 getdevvp sys/kern/vfs_subr.c:535 [inline] cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 sys/kern/vfs_subr.c:509 spec_open_clone(ffff800025db3e68) at spec_open_clone+0x193 sys/kern/spec_vnops.c:728 spec_open(ffff800025db3e68) at spec_open+0x3fd sys/kern/spec_vnops.c:153 VOP_OPEN(fffffd806f1f3390,1,fffffd807f7d74e0,ffff80002701ad30) at VOP_OPEN+0x75 sys/kern/vfs_vops.c:138 vn_open(ffff800025db40b8,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:180 doopenat(ffff80002701ad30,ffffff9c,20000000,0,0,ffff800025db4290) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800025db4310) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline] syscall(ffff800025db4310) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xe6a50e07c80, count: -12 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff800025db3af0 rbx 0xffffffff82945b97 cpu_info_full_primary+0x2b97 rdx 0 rcx 0 rax 0xffff80002701ad30 r8 0x101010101010101 r9 0x8080808080808080 r10 0x637780ff8a3532a5 r11 0x30d386ba37d2ad94 r12 0xffffffff82945998 cpu_info_full_primary+0x2998 r13 0 r14 0 r15 0x1 rip 0xffffffff810a3548 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800025db3ae0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.5) pid=215588 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff80002701a7f0,0xffff8000ffff22b0 process=0xffff800021299d28 user=0xffff800025daf000, vmspace=0xfffffd8068e35190 estcpu=36, cpticks=3, pctcpu=0.0 user=0, sys=3, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 89811 439569 57672 0 2 0 syz-executor.0 40826 183015 88218 0 2 0 syz-executor.6 40826 180496 88218 0 2 0x4000000 syz-executor.6 38873 382903 88056 0 2 0 syz-executor.5 *38873 215588 88056 0 7 0x4000000 syz-executor.5 44547 97647 1613 0 2 0 syz-executor.1 44547 315874 1613 0 3 0x4000080 fsleep syz-executor.1 3409 30579 1 0 3 0x100083 ttyin getty 75122 455958 32445 0 3 0x2 biowait syz-executor.7 57850 259986 32445 0 3 0x82 nanoslp syz-executor.2 1613 121173 32445 0 3 0x82 nanoslp syz-executor.1 6489 283907 32445 0 3 0x2 biowait syz-executor.3 79945 191907 0 0 3 0x14200 acct acct 30896 290520 32445 0 3 0x2 biowait syz-executor.4 88056 106461 32445 0 3 0x82 nanoslp syz-executor.5 57672 371942 32445 0 3 0x82 nanoslp syz-executor.0 92840 438162 0 0 3 0x14280 nfsidl nfsio 8164 262889 0 0 3 0x14280 nfsidl nfsio 82182 300295 0 0 3 0x14280 nfsidl nfsio 58833 393574 0 0 3 0x14280 nfsidl nfsio 66722 111677 0 0 3 0x14280 nfsidl nfsio 40896 155260 0 0 3 0x14280 nfsidl nfsio 76368 25757 0 0 3 0x14280 nfsidl nfsio 35755 211394 0 0 3 0x14280 nfsidl nfsio 32814 117340 0 0 3 0x14280 nfsidl nfsio 85627 191819 0 0 3 0x14280 nfsidl nfsio 35216 456384 0 0 3 0x14280 nfsidl nfsio 1511 410964 0 0 3 0x14280 nfsidl nfsio 10290 484137 0 0 3 0x14280 nfsidl nfsio 90810 60204 0 0 3 0x14280 nfsidl nfsio 30870 5951 0 0 3 0x14280 nfsidl nfsio 70823 513413 0 0 3 0x14280 nfsidl nfsio 4427 164085 0 0 3 0x14280 nfsidl nfsio 78859 374138 0 0 3 0x14280 nfsidl nfsio 66551 521052 0 0 3 0x14280 nfsidl nfsio 93152 248769 0 0 3 0x14280 nfsidl nfsio 76658 184746 0 0 3 0x14200 bored sosplice 88218 119830 32445 0 3 0x82 nanoslp syz-executor.6 32445 410393 84061 0 3 0x82 thrsleep syz-fuzzer 32445 398177 84061 0 3 0x4000082 nanoslp syz-fuzzer 32445 88950 84061 0 3 0x4000082 thrsleep syz-fuzzer 32445 445477 84061 0 3 0x4000082 nanoslp syz-fuzzer 32445 320300 84061 0 3 0x4000082 wait syz-fuzzer 32445 365105 84061 0 3 0x4000082 thrsleep syz-fuzzer 32445 95366 84061 0 3 0x4000082 wait syz-fuzzer 32445 516688 84061 0 3 0x4000082 thrsleep syz-fuzzer 32445 335073 84061 0 3 0x4000082 wait syz-fuzzer 32445 286817 84061 0 3 0x4000082 wait syz-fuzzer 32445 122142 84061 0 3 0x4000082 kqread syz-fuzzer 32445 266874 84061 0 3 0x4000082 wait syz-fuzzer 32445 364364 84061 0 3 0x4000082 thrsleep syz-fuzzer 32445 443162 84061 0 3 0x4000082 wait syz-fuzzer 32445 453676 84061 0 3 0x4000082 thrsleep syz-fuzzer 32445 323636 84061 0 3 0x4000082 wait syz-fuzzer 32445 225624 84061 0 3 0x4000082 wait syz-fuzzer 84061 245218 46716 0 3 0x10008a sigsusp ksh 46716 29722 42648 0 3 0x9a kqread sshd 42648 281709 1 0 3 0x88 kqread sshd 97194 9567 33906 74 3 0x1100092 bpf pflogd 33906 117055 1 0 3 0x80 netio pflogd 17833 398111 84936 73 3 0x1100090 kqread syslogd 84936 161432 1 0 3 0x100082 netio syslogd 77973 460033 1 0 3 0x100080 kqread resolvd 70073 188998 43500 77 3 0x100092 kqread dhcpleased 71075 144794 43500 77 3 0x100092 kqread dhcpleased 43500 74599 1 0 3 0x80 kqread dhcpleased 71378 488316 0 0 3 0x14200 bored smr 37481 232837 0 0 2 0x14200 zerothread 34539 12151 0 0 3 0x14200 aiodoned aiodoned 35163 95182 0 0 3 0x14200 syncer update 97707 266932 0 0 3 0x14200 cleaner cleaner 24575 93408 0 0 3 0x14200 reaper reaper 76235 326592 0 0 3 0x14200 pgdaemon pagedaemon 62210 274993 0 0 3 0x14200 bored viomb 51207 79247 0 0 3 0x40014200 acpi0 acpi0 92409 35952 0 0 7 0x40014200 idle1 4490 467653 0 0 3 0x14200 bored softnet 41517 265335 0 0 3 0x14200 bored softnet 30299 21123 0 0 3 0x14200 bored softnet 99727 415207 0 0 3 0x14200 bored softnet 90860 176061 0 0 3 0x14200 bored systqmp 40706 300906 0 0 3 0x14200 bored systq 53496 432721 0 0 3 0x40014200 bored softclock 71085 522269 0 0 3 0x40014200 idle0 1 343910 0 0 3 0x80082 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10193 6551K 7124K 78643K 15568 0 pcb 14 9K 10K 78643K 733 0 rtable 154 17K 17K 78643K 1024 0 ifaddr 74 17K 18K 78643K 886 0 sysctl 2 0K 1K 78643K 6 0 counters 48 34K 35K 78643K 210 0 ioctlops 0 0K 4K 78643K 2259 0 iov 0 0K 36K 78643K 266 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1333 83K 84K 78643K 3606 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 17K 78643K 49 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 151 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 14 49K 81K 78643K 7799 0 sigio 0 0K 0K 78643K 111 0 proc 71 91K 139K 78643K 1288 0 subproc 104 6K 6K 78643K 287 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 428 0 in_multi 46 3K 7K 78643K 407 0 ether_multi 1 0K 0K 78643K 61 0 mrt 1 0K 0K 78643K 49 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 115 519K 519K 78643K 115 0 exec 0 0K 2K 78643K 1350 0 pfkey data 0 0K 0K 78643K 16 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 62K 78643K 8 0 UVM amap 289 296K 320K 78643K 39209 0 UVM aobj 55 2K 2K 78643K 69 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 318 0 NDP 9 0K 1K 78643K 141 0 temp 117 4726K 4844K 78643K 57147 0 kqueue 12 18K 30K 78643K 697 0 SYN cache 2 16K 16K 78643K 2 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 120 326 0 323 3 2 1 3 0 8 0 rtentry 112 300 0 245 6 4 2 4 0 8 0 unpcb 144 1923 0 1908 4 3 1 2 0 8 0 syncache 296 51 0 51 7 7 0 1 0 8 0 tcpqe 32 103 0 103 7 7 0 1 0 8 0 tcpcb 736 1145 0 1141 15 14 1 4 0 8 0 arp 120 47 0 37 1 0 1 1 0 8 0 ipq 40 5 0 4 2 1 1 1 0 8 0 ipqe 40 9 0 8 2 1 1 1 0 8 0 inpcb 320 2952 0 2944 10 6 4 4 0 8 3 nd6 48 74 0 61 2 1 1 1 0 8 0 pkpcb 40 27 0 27 3 3 0 1 0 8 0 kcovpl 48 22 0 14 1 0 1 1 0 8 0 ppxss 1256 19 0 19 4 4 0 1 0 8 0 pfstscr 40 102 0 101 5 4 1 1 0 8 0 pffrag 232 2 0 2 1 1 0 1 0 482 0 pffrnode 88 2 0 2 1 1 0 1 0 8 0 pffrent 40 4 0 4 1 1 0 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 pfrktable 1344 35 0 26 1 0 1 1 0 8 0 pfanchor 1280 147 0 132 3 0 3 3 0 8 0 pftag 88 16 0 4 1 0 1 1 0 8 0 pfstitem 24 56 0 52 1 0 1 1 0 8 0 pfstkey 120 179 0 175 2 1 1 2 0 8 0 pfstate 336 114 0 111 4 3 1 4 0 8 0 pfrule 1360 235 0 163 7 1 6 6 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 1337 0 1120 51 37 14 29 0 8 0 art_table 32 1338 0 1120 6 4 2 4 0 8 0 art_node 16 295 0 248 1 0 1 1 0 8 0 sysvmsgpl 40 69 0 29 1 0 1 1 0 8 0 semapl 112 139 0 129 1 0 1 1 0 8 0 shmpl 112 66 0 14 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 11435 0 9980 92 0 92 92 0 8 0 ffsino 272 11435 0 9980 98 0 98 98 0 8 0 nchpl 144 20710 0 19059 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 54050 0 54048 6 5 1 2 0 8 0 percpumem 16 117 0 81 1 0 1 1 0 8 0 vcpupl 2048 15 0 1 2 0 2 2 0 8 0 vmpool 568 19 0 5 3 1 2 2 0 8 0 pfiaddrpl 120 115 0 17 3 0 3 3 0 8 0 kstatmem 264 180 0 162 2 0 2 2 0 8 0 scsiplug 72 13 0 13 3 3 0 1 0 8 0 scxspl 216 70109 0 70106 14 13 1 8 0 8 0 plimitpl 152 275 0 260 1 0 1 1 0 8 0 sigapl 424 8098 0 8031 9 1 8 8 0 8 0 futexpl 64 45040 0 45039 6 5 1 1 0 8 0 knotepl 120 607 0 0 17 0 17 17 0 8 0 kqueuepl 216 949 0 941 1 0 1 1 0 8 0 pipepl 320 506 0 478 3 0 3 3 0 8 0 fdescpl 496 8059 0 8032 5 1 4 5 0 8 0 filepl 152 23597 0 23357 21 9 12 13 0 8 2 lockfpl 104 1185 0 1183 1 0 1 1 0 8 0 lockfspl 48 442 0 440 1 0 1 1 0 8 0 sessionpl 144 40 0 23 1 0 1 1 0 8 0 pgrppl 48 49 0 32 1 0 1 1 0 8 0 ucredpl 104 3023 0 3011 1 0 1 1 0 8 0 zombiepl 144 8032 0 8031 1 0 1 1 0 8 0 processpl 1064 8098 0 8031 5 0 5 5 0 8 0 procpl 672 16442 0 16356 17 8 9 9 0 8 1 srpgc 96 30 0 30 3 3 0 1 0 8 0 sosppl 168 71 0 71 5 5 0 1 0 8 0 sockpl 488 5232 0 5206 23 15 8 12 0 8 4 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 6 0 0 1 0 1 1 0 8 0 mcl8k 8192 8 0 0 1 0 1 1 0 8 0 mcl4k 4096 13 0 0 2 0 2 2 0 8 0 mcl2k2 2112 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 281 0 0 18 0 18 18 0 8 0 mtagpl 96 185 0 0 4 1 3 4 0 8 0 mbufpl 256 857 0 0 41 0 41 41 0 8 0 bufpl 288 17222 0 10893 453 0 453 453 0 8 0 anonpl 24 1463151 0 1453970 241 161 80 155 0 186 0 amapchunkpl 152 114104 0 113603 52 29 23 32 0 158 0 amappl16 200 25594 0 25340 144 126 18 60 0 8 2 amappl15 192 1547 0 1539 1 0 1 1 0 8 0 amappl14 184 564 0 560 1 0 1 1 0 8 0 amappl13 176 1886 0 1884 1 0 1 1 0 8 0 amappl12 168 729 0 725 1 0 1 1 0 8 0 amappl11 160 693 0 674 1 0 1 1 0 8 0 amappl10 152 678 0 668 1 0 1 1 0 8 0 amappl9 144 2140 0 2133 1 0 1 1 0 8 0 amappl8 136 1338 0 1240 4 0 4 4 0 8 0 amappl7 128 560 0 539 1 0 1 1 0 8 0 amappl6 120 1966 0 1945 2 1 1 2 0 8 0 amappl5 112 6834 0 6815 1 0 1 1 0 8 0 amappl4 104 1920 0 1889 2 0 2 2 0 8 0 amappl3 96 22124 0 22073 2 0 2 2 0 8 0 amappl2 88 3036 0 2995 2 0 2 2 0 8 0 amappl1 80 187361 0 186722 20 4 16 20 0 8 0 amappl 88 38225 0 38073 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 68 0 14 1 0 1 1 0 8 0 uaddrrnd 24 8078 0 8037 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 8078 0 8037 1 0 1 1 0 8 0 vmmpekpl 168 43195 0 43123 4 0 4 4 0 8 0 vmmpepl 168 754376 0 752218 199 86 113 150 0 357 5 vmsppl 368 8077 0 8037 9 4 5 5 0 8 0 rwobjpl 56 177321 0 170040 129 23 106 117 0 8 0 pdppl 4096 16163 0 16088 258 175 83 84 0 8 8 pvpl 32 3278454 0 3264715 455 297 158 263 0 265 10 pmappl 248 8077 0 8037 4 1 3 3 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 1070 0 245 24 0 24 24 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(ffffffff8259bb45) at panic+0x177 sys/kern/subr_prf.c:202 malloc(38,19,1) at malloc+0xa85 sys/kern/kern_malloc.c:363 checkalias(fffffd807bcfa010,31700,0) at checkalias+0x269 sys/kern/vfs_subr.c:586 cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 getdevvp sys/kern/vfs_subr.c:535 [inline] cdevvp(31700,ffff800025db3d90) at cdevvp+0x98 sys/kern/vfs_subr.c:509 spec_open_clone(ffff800025db3e68) at spec_open_clone+0x193 sys/kern/spec_vnops.c:728 spec_open(ffff800025db3e68) at spec_open+0x3fd sys/kern/spec_vnops.c:153 VOP_OPEN(fffffd806f1f3390,1,fffffd807f7d74e0,ffff80002701ad30) at VOP_OPEN+0x75 sys/kern/vfs_vops.c:138 vn_open(ffff800025db40b8,1,0) at vn_open+0x467 sys/kern/vfs_vnops.c:180 doopenat(ffff80002701ad30,ffffff9c,20000000,0,0,ffff800025db4290) at doopenat+0x26a sys/kern/vfs_syscalls.c:1131 syscall(ffff800025db4310) at syscall+0x435 mi_syscall sys/sys/syscall_mi.h:101 [inline] syscall(ffff800025db4310) at syscall+0x435 sys/arch/amd64/amd64/trap.c:585 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xe6a50e07c80, count: -12 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:178 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:178 end trace frame: 0x0, count: -5