panic: Data modified on freelist: word 5 of object 0xffff800000b6e900 size 0x84 previous type devbuf (0xd != 0xdead4110) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *259099 87901 0 0x2044 0 0 syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 malloc(84,3f,1) at malloc+0xa23 sys/kern/kern_malloc.c:331 sys_execve(ffff80001596b168,ffff800014914850,ffff8000149148a0) at sys_execve+0xde sys/kern/kern_exec.c:286 syscall(ffff800014914920) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,3b,0,3b,7f7ffffc7992,0) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7940, count: 9 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 Data modified on freelist: word 5 of object 0xffff800000b6e900 size 0x84 previous type devbuf (0xd != 0xdead4110) ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 malloc(84,3f,1) at malloc+0xa23 sys/kern/kern_malloc.c:331 sys_execve(ffff80001596b168,ffff800014914850,ffff8000149148a0) at sys_execve+0xde sys/kern/kern_exec.c:286 syscall(ffff800014914920) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,3b,0,3b,7f7ffffc7992,0) at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc7940, count: -6 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff800014914210 rbx 0xffff8000149142c0 rdx 0x2 rcx 0 rax 0 r8 0xffff8000149141d0 r9 0x1 r10 0 r11 0x6397fa631f9b9c2a r12 0x3000000008 r13 0xffff800014914220 r14 0x100 r15 0x1 rip 0xffffffff81605488 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800014914200 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.0) pid=259099 stat=onproc flags process=2044 proc=0 pri=60, usrpri=60, nice=20 forw=0xffffffffffffffff, list=0xffff80001596a298,0xffffffff8255d430 process=0xffff8000148a3458 user=0xffff80001490f000, vmspace=0xfffffd803f013330 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND *87901 259099 80896 0 7 0x2044 syz-executor.0 80896 1773 77464 0 3 0x82 ppwait syz-executor.0 51908 310037 0 0 3 0x14200 acct acct 69218 280314 1 0 3 0x100083 ttyin getty 20370 397383 77464 0 3 0x82 piperd syz-executor.1 66067 283723 0 0 3 0x14200 bored sosplice 77464 491979 7382 0 3 0x82 thrsleep syz-fuzzer 77464 413684 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 28749 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 302535 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 499782 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 225894 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 164955 7382 0 3 0x4000082 thrsleep syz-fuzzer 77464 204662 7382 0 3 0x4000082 kqread syz-fuzzer 7382 269609 57683 0 3 0x10008a pause ksh 57683 497890 47611 0 3 0x92 select sshd 47611 373981 1 0 3 0x80 select sshd 2886 168097 63039 73 3 0x100090 kqread syslogd 63039 426772 1 0 3 0x100082 netio syslogd 56818 469669 1 77 3 0x100090 poll dhclient 66182 390948 1 0 3 0x80 poll dhclient 76312 157159 0 0 2 0x14200 zerothread 8934 128276 0 0 3 0x14200 aiodoned aiodoned 49795 474424 0 0 3 0x14200 syncer update 18685 342131 0 0 3 0x14200 cleaner cleaner 65286 345174 0 0 3 0x14200 reaper reaper 27212 286502 0 0 3 0x14200 pgdaemon pagedaemon 19719 451197 0 0 3 0x14200 bored crynlk 98085 243701 0 0 3 0x14200 bored crypto 4811 320198 0 0 3 0x40014200 acpi0 acpi0 28401 348421 0 0 3 0x14200 bored softnet 10162 231178 0 0 3 0x14200 bored systqmp 15872 88784 0 0 3 0x14200 bored systq 50179 236106 0 0 3 0x40014200 bored softclock 82433 76643 0 0 3 0x40014200 idle0 57993 361637 0 0 3 0x14200 bored smr 1 495340 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 Kern Lim devbuf 9548 6358K 7896K 78643K 14866 0 0 pcb 13 8K 8K 78643K 240 0 0 rtable 88 5K 7K 78643K 759 0 0 ifaddr 72 14K 15K 78643K 185 0 0 counters 19 16K 16K 78643K 19 0 0 ioctlops 0 0K 2K 78643K 74 0 0 iov 0 0K 28K 78643K 259 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1222 77K 77K 78643K 2990 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 14 0 0 VM map 8 2K 2K 78643K 14 0 0 sem 12 1K 1K 78643K 140 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1793 195K 288K 78643K 12645 0 0 file desc 5 13K 25K 78643K 1057 0 0 sigio 0 0K 0K 78643K 2 0 0 proc 48 38K 63K 78643K 647 0 0 subproc 32 2K 2K 78643K 140 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 82 0 0 in_multi 13 0K 2K 78643K 158 0 0 ether_multi 1 0K 0K 78643K 13 0 0 mrt 0 0K 0K 78643K 6 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 78 344K 344K 78643K 78 0 0 exec 0 0K 1K 78643K 354 0 0 pfkey data 0 0K 4K 78643K 2 0 0 pagedep 1 8K 8K 78643K 1 0 0 inodedep 1 32K 32K 78643K 1 0 0 newblk 1 0K 0K 78643K 1 0 0 VM swap 7 26K 26K 78643K 7 0 0 UVM amap 116 55K 60K 78643K 3857 0 0 UVM aobj 42 2K 2K 78643K 42 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 0K 78643K 254 0 0 NDP 18 0K 0K 78643K 60 0 0 temp 213 3544K 4184K 78643K 29009 0 0 kqueue 0 0K 0K 78643K 6 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 22 0 18 1 0 1 1 0 8 0 rtpcb 80 142 0 140 1 0 1 1 0 8 0 rtentry 112 153 0 125 2 0 2 2 0 8 0 unpcb 120 509 0 501 1 0 1 1 0 8 0 syncache 264 7 0 7 4 3 1 1 0 8 1 tcpqe 32 119 0 119 2 1 1 1 0 8 1 tcpcb 544 367 0 363 1 0 1 1 0 8 0 ipq 40 7 0 7 3 3 0 1 0 8 0 ipqe 40 91 0 91 3 3 0 1 0 8 0 inpcb 280 1384 0 1377 8 7 1 2 0 8 0 rttmr 72 3 0 2 2 1 1 1 0 8 0 nd6 48 23 0 23 2 1 1 1 0 8 1 pkpcb 40 4 0 4 2 2 0 1 0 8 0 ppxss 1128 7 0 7 6 6 0 1 0 8 0 art_heap8 4096 4 0 3 4 3 1 3 0 8 0 art_heap4 256 711 0 550 21 8 13 16 0 8 1 art_table 32 715 0 553 2 0 2 2 0 8 0 art_node 16 150 0 124 1 0 1 1 0 8 0 sysvmsgpl 40 50 0 39 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 138 0 128 1 0 1 1 0 8 0 shmpl 112 40 0 0 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 2943 0 1548 46 0 46 46 0 8 0 ffsino 240 2943 0 1548 83 0 83 83 0 8 0 nchpl 144 4681 0 4252 60 41 19 60 0 8 0 uvmvnodes 72 4526 0 0 83 0 83 83 0 8 0 vnodes 208 4526 0 0 239 0 239 239 0 8 0 namei 1024 15539 0 15539 3 2 1 1 0 8 1 vcpupl 1984 6 0 0 1 0 1 1 0 8 0 vmpool 520 12 0 6 1 0 1 1 0 8 0 scxspl 192 15373 0 15373 17 16 1 7 0 8 1 plimitpl 152 120 0 113 1 0 1 1 0 8 0 sigapl 432 1211 0 1198 2 0 2 2 0 8 0 futexpl 56 31895 0 31895 1 0 1 1 0 8 1 knotepl 112 729 0 708 1 0 1 1 0 8 0 kqueuepl 104 998 0 996 1 0 1 1 0 8 0 pipepl 112 660 0 641 4 3 1 2 0 8 0 fdescpl 424 1212 0 1198 2 0 2 2 0 8 0 filepl 120 10471 0 10376 10 5 5 5 0 8 2 lockfpl 104 463 0 462 1 0 1 1 0 8 0 lockfspl 48 153 0 152 1 0 1 1 0 8 0 sessionpl 112 24 0 14 1 0 1 1 0 8 0 pgrppl 48 44 0 34 1 0 1 1 0 8 0 ucredpl 96 1058 0 1051 1 0 1 1 0 8 0 zombiepl 144 1198 0 1198 2 1 1 1 0 8 1 processpl 864 1228 0 1198 4 0 4 4 0 8 0 procpl 632 2852 0 2815 9 4 5 5 0 8 1 sosppl 128 18 0 18 7 6 1 1 0 8 1 sockpl 384 2059 0 2042 9 6 3 5 0 8 1 mcl64k 65536 360 0 360 34 33 1 32 0 8 1 mcl16k 16384 18 0 18 6 5 1 1 0 8 1 mcl12k 12288 27 0 27 5 4 1 1 0 8 1 mcl9k 9216 21 0 21 6 5 1 1 0 8 1 mcl8k 8192 52 0 52 3 2 1 1 0 8 1 mcl4k 4096 154 0 154 2 1 1 1 0 8 1 mcl2k2 2112 10 0 10 8 7 1 1 0 8 1 mcl2k 2048 65794 0 65748 21 14 7 18 0 8 0 mtagpl 80 71 0 71 5 4 1 1 0 8 1 mbufpl 256 113886 0 113821 62 52 10 35 0 8 0 bufpl 256 10619 0 4497 383 0 383 383 0 8 0 anonpl 16 184537 0 169763 128 48 80 113 0 62 1 amapchunkpl 152 7809 0 7674 37 29 8 17 0 158 2 amappl16 192 8714 0 7645 99 43 56 67 0 8 1 amappl15 184 1 0 1 1 1 0 1 0 8 0 amappl14 176 82 0 79 2 1 1 1 0 8 0 amappl13 168 2 0 2 2 2 0 1 0 8 0 amappl12 160 489 0 486 1 0 1 1 0 8 0 amappl11 152 64 0 53 1 0 1 1 0 8 0 amappl10 144 19 0 19 2 1 1 1 0 8 1 amappl9 136 962 0 954 1 0 1 1 0 8 0 amappl8 128 530 0 488 2 0 2 2 0 8 0 amappl7 120 58 0 52 1 0 1 1 0 8 0 amappl6 112 86 0 72 2 1 1 1 0 8 0 amappl5 104 669 0 659 1 0 1 1 0 8 0 amappl4 96 1062 0 1035 1 0 1 1 0 8 0 amappl3 88 519 0 514 1 0 1 1 0 8 0 amappl2 80 8425 0 8365 4 2 2 3 0 8 0 amappl1 72 32448 0 32058 26 17 9 20 0 8 0 amappl 80 3191 0 3147 2 0 2 2 0 84 0 dma4096 4096 1 0 1 1 1 0 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 17 0 17 1 1 0 1 0 8 0 aobjpl 64 41 0 0 1 0 1 1 0 8 0 uaddrrnd 24 1224 0 1198 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 1224 0 1198 1 0 1 1 0 8 0 vmmpekpl 168 12641 0 12612 2 0 2 2 0 8 0 vmmpepl 168 157649 0 155518 234 92 142 147 0 357 40 vmsppl 272 1211 0 1198 4 2 2 2 0 8 1 pdppl 4096 2454 0 2414 7 1 6 6 0 8 0 pvpl 32 507201 0 490167 350 85 265 313 0 265 85 pmappl 200 1223 0 1204 2 0 2 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 639 0 125 16 0 16 16 0 8 0