panic: Data modified on freelist: word 4 of object 0xffff800000b89800 size 0x100 previous type free (0xffff3160 != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *133610 86478 0 0 0x4000000 0 syz-executor.1 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(100,2,a) at malloc+0xa23 sys/kern/kern_malloc.c:331 bpfopen(21700,1,2000,ffff8000ffff4ee0) at bpfopen+0xb5 sys/net/bpf.c:360 spec_open_clone(ffff8000179cefb8) at spec_open_clone+0x241 sys/kern/spec_vnops.c:737 spec_open(ffff8000179cefb8) at spec_open+0x40e VOP_OPEN(fffffd80268ba000,1,fffffd803f7c6a80,ffff8000ffff4ee0) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:154 vn_open(ffff8000179cf208,1,0) at vn_open+0x4eb sys/kern/vfs_vnops.c:186 doopenat(ffff8000ffff4ee0,ffffff9c,20000300,0,0,ffff8000179cf400) at doopenat+0x28b sys/kern/vfs_syscalls.c:1157 syscall(ffff8000179cf480) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffa2,0,4,8d3b65d9010) at Xsyscall+0x128 end of kernel end trace frame: 0x8d5ea46a130, 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 Data modified on freelist: word 4 of object 0xffff800000b89800 size 0x100 previous type free (0xffff3160 != 0xdeafbead) 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(100,2,a) at malloc+0xa23 sys/kern/kern_malloc.c:331 bpfopen(21700,1,2000,ffff8000ffff4ee0) at bpfopen+0xb5 sys/net/bpf.c:360 spec_open_clone(ffff8000179cefb8) at spec_open_clone+0x241 sys/kern/spec_vnops.c:737 spec_open(ffff8000179cefb8) at spec_open+0x40e VOP_OPEN(fffffd80268ba000,1,fffffd803f7c6a80,ffff8000ffff4ee0) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:154 vn_open(ffff8000179cf208,1,0) at vn_open+0x4eb sys/kern/vfs_vnops.c:186 doopenat(ffff8000ffff4ee0,ffffff9c,20000300,0,0,ffff8000179cf400) at doopenat+0x28b sys/kern/vfs_syscalls.c:1157 syscall(ffff8000179cf480) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffa2,0,4,8d3b65d9010) at Xsyscall+0x128 end of kernel end trace frame: 0x8d5ea46a130, count: -11 ddb> show registers rdi 0xffffffff81939467 db_enter+0x17 rsi 0x86de __ALIGN_SIZE+0x76de rbp 0xffff8000179cecc0 rbx 0xffff8000179ced70 rdx 0x86df __ALIGN_SIZE+0x76df rcx 0xffff800017788000 rax 0xffff800017788000 r8 0xffff8000179cec80 r9 0x1 r10 0xffff800000a682c0 r11 0xd57c150ce0de83a0 r12 0x3000000008 r13 0xffff8000179cecd0 r14 0x100 r15 0x1 rip 0xffffffff81939468 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000179cecb0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=133610 stat=onproc flags process=0 proc=4000000 pri=75, usrpri=75, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff49f0,0xffffffff82561488 process=0xffff8000ffff6a30 user=0xffff8000179ca000, vmspace=0xfffffd803f013cc0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 86478 455150 47944 0 2 0 syz-executor.1 *86478 133610 47944 0 7 0x4000000 syz-executor.1 34374 96212 63991 0 2 0x2 syz-executor.0 47944 354418 63991 0 3 0x82 nanosleep syz-executor.1 47319 129014 0 0 3 0x14200 acct acct 28555 194733 1 0 3 0x100083 ttyin getty 50370 314172 0 0 3 0x14200 bored sosplice 63991 514804 73334 0 3 0x82 thrsleep syz-fuzzer 63991 319296 73334 0 3 0x4000082 nanosleep syz-fuzzer 63991 494796 73334 0 3 0x4000082 thrsleep syz-fuzzer 63991 440501 73334 0 3 0x4000082 thrsleep syz-fuzzer 63991 506293 73334 0 3 0x4000082 kqread syz-fuzzer 63991 239872 73334 0 3 0x4000082 thrsleep syz-fuzzer 63991 185991 73334 0 3 0x4000082 thrsleep syz-fuzzer 63991 66403 73334 0 3 0x4000082 thrsleep syz-fuzzer 73334 237002 38650 0 3 0x10008a pause ksh 38650 84953 12925 0 3 0x92 select sshd 12925 251189 1 0 3 0x80 select sshd 34866 351030 89094 73 3 0x100090 kqread syslogd 89094 487450 1 0 3 0x100082 netio syslogd 23665 163855 0 0 2 0x14200 zerothread 70563 457853 0 0 3 0x14200 aiodoned aiodoned 53881 472208 0 0 3 0x14200 syncer update 16242 232452 0 0 3 0x14200 cleaner cleaner 16488 55293 0 0 3 0x14200 reaper reaper 11275 193647 0 0 3 0x14200 pgdaemon pagedaemon 5511 452567 0 0 3 0x14200 bored crynlk 60219 520962 0 0 3 0x14200 bored crypto 50592 359914 0 0 3 0x40014200 acpi0 acpi0 90366 29055 0 0 3 0x14200 bored softnet 24292 12835 0 0 3 0x14200 bored systqmp 17105 317405 0 0 3 0x14200 bored systq 99313 491239 0 0 3 0x40014200 bored softclock 86142 497909 0 0 3 0x40014200 idle0 31228 113246 0 0 3 0x14200 bored smr 1 14824 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 9599 6963K 7674K 78643K 29720 0 0 pcb 13 10K 12K 78643K 1858 0 0 rtable 95 12K 13K 78643K 4858 0 0 ifaddr 92 24K 29K 78643K 1503 0 0 counters 19 16K 16K 78643K 19 0 0 ioctlops 0 0K 2K 78643K 628 0 0 iov 0 0K 32K 78643K 2394 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1216 76K 77K 78643K 9263 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 9K 78643K 178 0 0 VM map 85 21K 21K 78643K 140 0 0 sem 12 0K 1K 78643K 2934 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1793 195K 288K 78643K 12645 0 0 file desc 5 13K 25K 78643K 8845 0 0 sigio 0 0K 0K 78643K 190 0 0 proc 45 30K 55K 78643K 3060 0 0 subproc 32 2K 2K 78643K 854 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 744 0 0 in_multi 15 0K 2K 78643K 918 0 0 ether_multi 1 0K 0K 78643K 59 0 0 mrt 2 0K 0K 78643K 40 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 114 503K 503K 78643K 114 0 0 exec 0 0K 1K 78643K 1952 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 208 640K 642K 78643K 30546 0 0 UVM aobj 130 6K 6K 78643K 136 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 1K 78643K 1800 0 0 NDP 23 0K 1K 78643K 487 0 0 temp 247 3545K 4185K 78643K 389121 0 0 kqueue 0 0K 0K 78643K 97 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 64 191 0 188 1 0 1 1 0 8 0 rtpcb 80 1018 0 1018 14 13 1 1 0 8 1 rtentry 112 923 0 894 2 0 2 2 0 8 0 unpcb 120 8539 0 8520 39 37 2 3 0 8 0 syncache 264 43 0 43 18 18 0 1 0 8 0 sackhl 24 2 0 2 2 2 0 1 0 8 0 tcpqe 32 159 0 159 8 8 0 1 0 8 0 tcpcb 544 17191 0 17186 89 87 2 4 0 8 1 ipq 40 99 0 99 48 48 0 1 0 8 0 ipqe 40 2326 0 2326 48 48 0 1 0 8 0 inpcb 280 25104 0 25099 120 118 2 13 0 8 1 rttmr 72 11 0 11 9 9 0 1 0 8 0 ip6q 72 3 0 3 3 3 0 1 0 8 0 ip6af 40 9 0 9 3 3 0 1 0 8 0 nd6 48 122 0 122 16 16 0 1 0 8 0 pkpcb 40 37 0 37 17 17 0 1 0 8 0 swfcl 56 10 0 0 1 0 1 1 0 8 0 ppxss 1128 160 0 160 69 68 1 1 0 8 1 art_heap8 4096 10 0 8 8 6 2 3 0 8 0 art_heap4 256 3738 0 3575 51 37 14 17 0 8 0 art_table 32 3748 0 3583 6 3 3 3 0 8 0 art_node 16 918 0 891 1 0 1 1 0 8 0 sysvmsgpl 40 104 0 71 1 0 1 1 0 8 0 semupl 112 3 0 3 1 1 0 1 0 8 0 semapl 112 2932 0 2922 1 0 1 1 0 8 0 shmpl 112 134 0 6 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 15245 0 13848 46 0 46 46 0 8 0 ffsino 240 15245 0 13848 83 0 83 83 0 8 0 nchpl 144 28208 0 27747 60 40 20 60 0 8 0 uvmvnodes 72 8822 0 0 161 0 161 161 0 8 0 vnodes 208 8822 0 0 465 0 465 465 0 8 0 namei 1024 95471 0 95471 7 6 1 1 0 8 1 vcpupl 1984 85 0 2 11 0 11 11 0 8 0 vmpool 520 138 0 55 10 4 6 6 0 8 0 scsiplug 64 7 0 7 6 6 0 1 0 8 0 scxspl 192 121087 0 121087 86 84 2 7 0 8 2 plimitpl 152 804 0 798 1 0 1 1 0 8 0 sigapl 432 8879 0 8868 2 0 2 2 0 8 0 futexpl 56 327183 0 327183 8 7 1 1 0 8 1 knotepl 112 2384 0 2365 6 5 1 3 0 8 0 kqueuepl 104 2475 0 2473 1 0 1 1 0 8 0 pipepl 112 5602 0 5583 24 23 1 2 0 8 0 fdescpl 424 8880 0 8868 2 0 2 2 0 8 0 filepl 120 92408 0 92320 98 94 4 11 0 8 1 lockfpl 104 3356 0 3356 8 7 1 1 0 8 1 lockfspl 48 1120 0 1120 8 7 1 1 0 8 1 sessionpl 112 72 0 64 1 0 1 1 0 8 0 pgrppl 48 176 0 168 1 0 1 1 0 8 0 ucredpl 96 10152 0 10145 1 0 1 1 0 8 0 zombiepl 144 8869 0 8869 1 0 1 1 0 8 1 processpl 864 8897 0 8869 4 0 4 4 0 8 0 procpl 632 27337 0 27301 66 61 5 5 0 8 1 sosppl 128 172 0 172 51 51 0 1 0 8 0 sockpl 384 34783 0 34759 245 240 5 22 0 8 1 mcl64k 65536 3227 0 3227 316 315 1 33 0 8 1 mcl16k 16384 150 0 150 80 79 1 1 0 8 1 mcl12k 12288 333 0 333 74 73 1 1 0 8 1 mcl9k 9216 179 0 179 79 78 1 1 0 8 1 mcl8k 8192 474 0 474 70 69 1 1 0 8 1 mcl4k 4096 1056 0 1056 19 18 1 1 0 8 1 mcl2k2 2112 84 0 84 48 48 0 1 0 8 0 mcl2k 2048 86917 0 86871 19 12 7 13 0 8 0 mtagpl 80 355 0 353 21 20 1 1 0 8 0 mbufpl 256 253281 0 253193 476 467 9 37 0 8 0 bufpl 256 49847 0 41022 552 0 552 552 0 8 0 anonpl 16 1145386 0 1124749 445 345 100 102 0 62 8 amapchunkpl 152 63009 0 62878 178 171 7 19 0 158 0 amappl16 192 56392 0 55155 557 482 75 78 0 8 12 amappl15 184 2064 0 2062 2 1 1 1 0 8 0 amappl14 176 1534 0 1530 1 0 1 1 0 8 0 amappl13 168 27 0 27 6 6 0 1 0 8 0 amappl12 160 1275 0 1272 1 0 1 1 0 8 0 amappl11 152 1705 0 1701 1 0 1 1 0 8 0 amappl10 144 2111 0 2107 1 0 1 1 0 8 0 amappl9 136 1716 0 1710 1 0 1 1 0 8 0 amappl8 128 1254 0 1209 3 1 2 2 0 8 0 amappl7 120 2358 0 2348 1 0 1 1 0 8 0 amappl6 112 1550 0 1535 1 0 1 1 0 8 0 amappl5 104 1916 0 1910 1 0 1 1 0 8 0 amappl4 96 8019 0 7992 1 0 1 1 0 8 0 amappl3 88 2499 0 2490 1 0 1 1 0 8 0 amappl2 80 68950 0 68881 3 1 2 3 0 8 0 amappl1 72 193214 0 192826 24 14 10 20 0 8 0 amappl 80 28308 0 28234 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 64 135 0 6 3 0 3 3 0 8 0 uaddrrnd 24 9018 0 8868 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 9018 0 8868 1 0 1 1 0 8 0 vmmpekpl 168 73446 0 73404 3 0 3 3 0 8 0 vmmpepl 168 1127900 0 1125416 1317 1176 141 157 0 357 21 vmsppl 272 8879 0 8868 21 20 1 2 0 8 0 pdppl 4096 18042 0 17929 25 10 15 15 0 8 0 pvpl 32 3124415 0 3102775 1398 1115 283 327 0 265 94 pmappl 200 9017 0 8923 7 1 6 6 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 1821 0 1128 23 1 22 22 0 8 0