panic: Data modified on freelist: word 4 of object 0xffff800000dac600 size 0x10c previous type free (0x6563 != 0xdeadbeef) Stopped at db_enter+0x1c: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 10000 42375 0 0x12 0x1 0 sshd db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff82781d37) at panic+0x165 sys/kern/subr_prf.c:198 malloc(10c,7f,1) at malloc+0xa85 sys/kern/kern_malloc.c:362 ktrgenio(ffff800021633800,4,1,ffff8000006c69f0,104) at ktrgenio+0x12e sys/kern/kern_ktrace.c:243 dofilewritev(ffff800021633800,4,ffff8000216a8748,0,ffff8000216a8830) at dofilewritev+0x38e sys/kern/sys_generic.c:396 sys_write(ffff800021633800,ffff8000216a87e0,ffff8000216a8830) at sys_write+0x87 sys/kern/sys_generic.c:295 syscall(ffff8000216a88b0) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x790e974ff330, count: 7 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 0xffff800000dac600 size 0x10c previous type free (0x6563 != 0xdeadbeef) ddb> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff82781d37) at panic+0x165 sys/kern/subr_prf.c:198 malloc(10c,7f,1) at malloc+0xa85 sys/kern/kern_malloc.c:362 ktrgenio(ffff800021633800,4,1,ffff8000006c69f0,104) at ktrgenio+0x12e sys/kern/kern_ktrace.c:243 dofilewritev(ffff800021633800,4,ffff8000216a8748,0,ffff8000216a8830) at dofilewritev+0x38e sys/kern/sys_generic.c:396 sys_write(ffff800021633800,ffff8000216a87e0,ffff8000216a8830) at sys_write+0x87 sys/kern/sys_generic.c:295 syscall(ffff8000216a88b0) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x790e974ff330, count: -8 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff8000216a8400 rbx 0xffff800000dac600 rdx 0 rcx 0 rax 0xffff800021633800 r8 0x101010101010101 r9 0x8080808080808080 r10 0xa39530d11d16458b r11 0x27f4ec284ecb77b8 r12 0 r13 0x51 r14 0 r15 0x1 rip 0xffffffff810aed4c db_enter+0x1c cs 0x8 rflags 0x246 rsp 0xffff8000216a83f0 ss 0x10 db_enter+0x1c: addq $0x8,%rsp ddb> show proc PROC (sshd) tid=10000 pid=42375 tcnt=1 stat=onproc flags process=12 proc=1 runpri=24, usrpri=50, slppri=24, nice=20 wchan=0x0, wmesg=, ps_single=0x0 forw=0xffffffffffffffff, list=0xffff800021689010,0xffff800021634d50 process=0xffff8000ffff87e0 user=0xffff8000216a3000, vmspace=0xfffffd807f0138a0 estcpu=0, cpticks=2, pctcpu=0.4, user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 24936 405567 9152 0 2 0 syz-executor.3 23996 152015 333 0 3 0x80 nanoslp syz-executor.5 23996 466128 333 0 3 0x4000080 fsleep syz-executor.5 13127 250197 42307 60928 3 0x90 nanoslp syz-executor.6 13127 215178 42307 60928 3 0x4000090 fsleep syz-executor.6 13127 212910 42307 60928 3 0x4000090 fsleep syz-executor.6 13127 27617 42307 60928 2 0x4000010 syz-executor.6 13127 53422 42307 60928 2 0x4000010 syz-executor.6 13127 272371 42307 60928 2 0x4000010 syz-executor.6 13127 260929 42307 60928 2 0x4000010 syz-executor.6 13127 161602 42307 60928 2 0x4000010 syz-executor.6 13127 287771 42307 60928 2 0x4000010 syz-executor.6 13127 311063 42307 60928 2 0x4000010 syz-executor.6 13127 10531 42307 60928 2 0x4000010 syz-executor.6 13127 263745 42307 60928 2 0x4000010 syz-executor.6 13127 5178 42307 60928 2 0x4000010 syz-executor.6 13127 114687 42307 60928 2 0x4000010 syz-executor.6 13127 507252 42307 60928 2 0x4000010 syz-executor.6 13127 41459 42307 60928 2 0x4000010 syz-executor.6 50140 345079 25774 0 2 0x480 syz-executor.4 50140 249006 25774 0 3 0x4000080 fsleep syz-executor.4 57929 303411 50604 0 3 0x82 nanoslp syz-executor.7 42307 333769 50604 0 3 0x82 nanoslp syz-executor.6 90082 245222 0 0 3 0x14200 acct acct 40910 41935 1 0 3 0x100083 ttyin getty 73592 444725 50604 0 2 0x2 syz-executor.2 34838 208511 50604 0 2 0x482 syz-executor.0 9152 282017 50604 0 3 0x82 nanoslp syz-executor.3 25774 511566 50604 0 3 0x82 nanoslp syz-executor.4 89764 74343 0 0 3 0x14280 nfsidl nfsio 33919 206701 0 0 3 0x14280 nfsidl nfsio 8877 422655 0 0 3 0x14280 nfsidl nfsio 87958 145705 0 0 3 0x14280 nfsidl nfsio 16497 32329 0 0 3 0x14280 nfsidl nfsio 81613 173310 0 0 3 0x14280 nfsidl nfsio 91780 471400 0 0 3 0x14280 nfsidl nfsio 56678 425382 0 0 3 0x14280 nfsidl nfsio 6445 76105 0 0 3 0x14280 nfsidl nfsio 42772 252087 0 0 3 0x14280 nfsidl nfsio 95829 117859 0 0 3 0x14280 nfsidl nfsio 84547 315197 0 0 3 0x14280 nfsidl nfsio 64415 131941 0 0 3 0x14280 nfsidl nfsio 70318 152626 0 0 3 0x14280 nfsidl nfsio 19193 388206 0 0 3 0x14280 nfsidl nfsio 18421 479828 0 0 3 0x14280 nfsidl nfsio 15687 97539 0 0 3 0x14280 nfsidl nfsio 96122 486109 0 0 3 0x14280 nfsidl nfsio 53199 343461 0 0 3 0x14280 nfsidl nfsio 93699 74636 0 0 3 0x14280 nfsidl nfsio 11183 435722 50604 0 3 0x82 nanoslp syz-executor.1 67935 363864 0 0 3 0x14200 bored sosplice 333 456170 50604 0 2 0x482 syz-executor.5 50604 464361 99218 0 3 0x2000082 wait syz-fuzzer 50604 521736 99218 0 3 0x6000082 nanoslp syz-fuzzer 50604 222896 99218 0 3 0x6000082 thrsleep syz-fuzzer 50604 114697 99218 0 3 0x6000082 wait syz-fuzzer 50604 241833 99218 0 3 0x6000082 thrsleep syz-fuzzer 50604 119861 99218 0 2 0x6000002 syz-fuzzer 50604 265742 99218 0 3 0x6000082 wait syz-fuzzer 50604 382926 99218 0 3 0x6000082 wait syz-fuzzer 50604 160566 99218 0 3 0x6000082 wait syz-fuzzer 50604 449971 99218 0 3 0x6000082 wait syz-fuzzer 50604 435132 99218 0 3 0x6000082 thrsleep syz-fuzzer 50604 148142 99218 0 3 0x6000082 thrsleep syz-fuzzer 50604 244326 99218 0 3 0x6000082 wait syz-fuzzer 50604 30486 99218 0 3 0x6000082 wait syz-fuzzer 99218 98530 42375 0 3 0x10008a sigsusp ksh *42375 10000 67304 0 7 0x13 sshd 67304 854 1 0 3 0x88 kqread sshd 71573 250774 38006 73 3 0x1100090 kqread syslogd 38006 49872 1 0 3 0x100082 netio syslogd 32411 157651 1 0 3 0x100080 kqread resolvd 49825 30552 90491 77 3 0x100092 kqread dhcpleased 94590 471363 90491 77 3 0x100092 kqread dhcpleased 90491 177946 1 0 3 0x80 kqread dhcpleased 69679 119190 0 0 3 0x14200 bored smr 13783 8963 0 0 2 0x14200 zerothread 33982 66493 0 0 3 0x14200 aiodoned aiodoned 45353 491730 0 0 3 0x14200 syncer update 33382 319715 0 0 3 0x14200 cleaner cleaner 91540 351887 0 0 3 0x14200 reaper reaper 35795 231106 0 0 3 0x14200 pgdaemon pagedaemon 43734 166759 0 0 3 0x14200 bored viomb 66931 518145 0 0 3 0x40014200 acpi0 acpi0 77283 442759 0 0 3 0x14200 bored softnet3 41147 458080 0 0 3 0x14200 bored softnet2 80495 420430 0 0 3 0x14200 bored softnet1 29663 374815 0 0 2 0x14200 softnet0 32027 522994 0 0 3 0x14200 bored systqmp 67002 420936 0 0 3 0x14200 bored systq 72081 286140 0 0 3 0x40014200 tmoslp softclock 88219 243495 0 0 3 0x40014200 idle0 1 91815 0 0 3 0x82 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 10190 6545K 7330K 78643K 40578 0 pcb 13 18K 20K 78643K 606 0 rtable 241 7K 7K 78643K 1507 0 pf 32 9K 10K 78643K 330 0 ifaddr 44 13K 14K 78643K 250 0 ifgroup 55 2K 2K 78643K 541 0 sysctl 3 0K 0K 78643K 15 0 counters 29 17K 17K 78643K 159 0 ioctlops 0 0K 2K 78643K 1278 0 iov 0 0K 32K 78643K 1213 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 4 0 vnodes 1531 96K 96K 78643K 9566 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 9K 78643K 127 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 439 0 dirhash 12 2K 2K 78643K 57 0 ACPI 1697 195K 286K 78643K 12548 0 file desc 14 49K 65K 78643K 10400 0 sigio 0 0K 0K 78643K 146 0 proc 58 59K 83K 78643K 1315 0 subproc 104 6K 6K 78643K 393 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 424 0 in_multi 99 7K 7K 78643K 446 0 ether_multi 1 0K 0K 78643K 22 0 mrt 1 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 73 334K 334K 78643K 73 0 exec 0 0K 1K 78643K 2121 0 pfkey data 0 0K 0K 78643K 5 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 413 323K 328K 78643K 96616 0 UVM aobj 131 4K 4K 78643K 134 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 12 0K 2K 78643K 202 0 temp 75 5916K 6044K 78643K 76120 0 kqueue 12 18K 24K 78643K 633 0 SYN cache 2 1236K 1244K 78643K 3 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 306 0 303 3 2 1 2 0 8 0 rtentry 112 431 0 319 4 0 4 4 0 8 0 unpcb 144 22591 0 22578 110 106 4 11 0 8 3 syncache 304 92 0 92 18 17 1 1 0 8 1 sackhl 24 3 0 3 3 3 0 1 0 8 0 tcpqe 32 244 0 244 12 11 1 1 0 8 1 tcpcb 808 2500 0 2478 94 89 5 14 0 8 2 arp 88 63 0 45 1 0 1 1 0 8 0 ipq 40 8 0 8 4 4 0 1 0 8 0 ipqe 40 20 0 20 4 4 0 1 0 8 0 inpcb 336 6292 0 6267 133 129 4 18 0 8 1 ip6q 72 4 0 3 2 1 1 1 0 8 0 ip6af 40 7 0 6 2 1 1 1 0 8 0 nd6 104 99 0 73 1 0 1 1 0 8 0 pkpcb 40 51 0 51 5 5 0 1 0 8 0 kcovpl 48 30 0 22 1 0 1 1 0 8 0 ppxss 1160 36 0 36 11 10 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 1486 0 1020 34 4 30 30 0 8 0 art_table 32 1487 0 1020 4 0 4 4 0 8 0 art_node 16 362 0 260 1 0 1 1 0 8 0 sysvmsgpl 40 1 0 0 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 399 0 389 1 0 1 1 0 8 0 shmpl 112 131 0 3 4 0 4 4 0 8 0 dirhash 1024 47 0 30 3 0 3 3 0 8 0 dino2pl 256 15686 0 14201 93 0 93 93 0 8 0 ffsino 240 15686 0 14201 88 0 88 88 0 8 0 nchpl 144 30965 0 30470 63 42 21 63 0 8 0 uvmvnodes 80 6544 0 0 134 0 134 134 0 8 0 vnodes 216 6544 0 0 364 0 364 364 0 8 0 namei 1024 105237 0 105237 11 9 2 2 0 8 2 vcpupl 2048 63 0 0 8 0 8 8 0 8 0 vmpool 664 69 0 6 6 0 6 6 0 8 0 kstatmem 264 284 0 260 2 0 2 2 0 8 0 scxspl 216 107317 0 107317 21 20 1 8 1 8 1 plimitpl 152 1146 0 1131 1 0 1 1 0 8 0 sigapl 424 10873 0 10807 10 2 8 8 0 8 0 futexpl 64 97918 0 97914 11 10 1 1 0 8 0 knotepl 120 90039 0 89958 28 25 3 11 0 8 0 kqueuepl 184 1475 0 1467 23 22 1 7 0 8 0 pipepl 288 1668 0 1640 29 26 3 11 0 8 0 fdescpl 432 10632 0 10607 4 0 4 4 0 8 0 filepl 120 77226 0 76985 112 102 10 19 0 8 2 lockfpl 104 5354 0 5352 12 11 1 3 0 8 0 lockfspl 48 2184 0 2182 1 0 1 1 0 8 0 sessionpl 144 47 0 31 1 0 1 1 0 8 0 pgrppl 48 168 0 152 1 0 1 1 0 8 0 ucredpl 104 8716 0 8704 1 0 1 1 0 8 0 zombiepl 144 10810 0 10807 2 1 1 1 0 8 0 processpl 1008 10873 0 10807 12 3 9 9 0 8 0 procpl 680 25884 0 25788 17 8 9 9 0 8 0 sosppl 168 82 0 82 10 9 1 1 0 8 1 sockpl 456 29261 0 29220 636 622 14 41 0 8 7 mcl64k 65536 350 0 350 18 17 1 1 0 8 1 mcl16k 16384 186 0 186 20 19 1 1 0 8 1 mcl12k 12288 332 0 332 18 17 1 1 0 8 1 mcl9k 9216 151 0 151 21 20 1 1 0 8 1 mcl8k 8192 811 0 810 13 12 1 1 0 8 0 mcl4k 4096 996 0 996 10 9 1 1 0 8 1 mcl2k2 2112 78 0 78 19 18 1 1 0 8 1 mcl2k 2048 85860 0 85791 50 38 12 28 0 8 1 mtagpl 96 2236 0 1886 24 14 10 13 0 8 0 mbufpl 256 231667 0 231218 347 312 35 87 0 8 0 bufpl 288 24919 0 18375 468 0 468 468 0 8 0 anonpl 24 1065339 0 1051133 213 114 99 117 0 188 0 amapchunkpl 152 305746 0 304942 95 58 37 47 0 158 1 amappl16 200 21278 0 20795 88 57 31 39 0 8 4 amappl15 192 23 0 22 1 0 1 1 0 8 0 amappl14 184 220 0 208 2 1 1 2 0 8 0 amappl13 176 14 0 14 2 2 0 1 0 8 0 amappl12 168 11604 0 11577 2 0 2 2 0 8 0 amappl11 160 60 0 49 1 0 1 1 0 8 0 amappl10 152 60 0 50 1 0 1 1 0 8 0 amappl9 144 177 0 176 1 0 1 1 0 8 0 amappl8 136 666 0 551 5 0 5 5 0 8 0 amappl7 128 296 0 272 2 0 2 2 0 8 0 amappl6 120 619 0 606 1 0 1 1 0 8 0 amappl5 112 267 0 258 1 0 1 1 0 8 0 amappl4 104 645 0 620 2 1 1 2 0 8 0 amappl3 96 60767 0 60700 4 1 3 3 0 8 0 amappl2 88 13535 0 13468 3 1 2 3 0 8 0 amappl1 80 47654 0 47152 22 10 12 22 0 8 0 amappl 88 95581 0 95352 7 0 7 7 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 72 133 0 3 3 0 3 3 0 8 0 uaddrrnd 24 10701 0 10613 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 10701 0 10613 1 0 1 1 0 8 0 vmmpekpl 168 71920 0 71846 4 0 4 4 0 8 0 vmmpepl 168 634582 0 632243 286 169 117 131 0 357 1 vmsppl 368 10700 0 10613 10 1 9 9 0 8 0 rwobjpl 24 154294 0 146089 53 2 51 51 0 8 0 pdppl 4096 21408 0 21289 510 385 125 127 0 8 6 pvpl 32 2991489 0 2972071 472 292 180 333 0 265 7 pmappl 216 10700 0 10613 10 4 6 6 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 1960 0 1060 28 0 28 28 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff82781d37) at panic+0x165 sys/kern/subr_prf.c:198 malloc(10c,7f,1) at malloc+0xa85 sys/kern/kern_malloc.c:362 ktrgenio(ffff800021633800,4,1,ffff8000006c69f0,104) at ktrgenio+0x12e sys/kern/kern_ktrace.c:243 dofilewritev(ffff800021633800,4,ffff8000216a8748,0,ffff8000216a8830) at dofilewritev+0x38e sys/kern/sys_generic.c:396 sys_write(ffff800021633800,ffff8000216a87e0,ffff8000216a8830) at sys_write+0x87 sys/kern/sys_generic.c:295 syscall(ffff8000216a88b0) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x790e974ff330, count: -8 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x1c sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff82781d37) at panic+0x165 sys/kern/subr_prf.c:198 malloc(10c,7f,1) at malloc+0xa85 sys/kern/kern_malloc.c:362 ktrgenio(ffff800021633800,4,1,ffff8000006c69f0,104) at ktrgenio+0x12e sys/kern/kern_ktrace.c:243 dofilewritev(ffff800021633800,4,ffff8000216a8748,0,ffff8000216a8830) at dofilewritev+0x38e sys/kern/sys_generic.c:396 sys_write(ffff800021633800,ffff8000216a87e0,ffff8000216a8830) at sys_write+0x87 sys/kern/sys_generic.c:295 syscall(ffff8000216a88b0) at syscall+0x4a8 sys/arch/amd64/amd64/trap.c:623 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x790e974ff330, count: -8