panic: Data modified on freelist: word 5 of object 0xffff800000b9da00 size 0xc0 previous type devbuf (0xd != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *321221 26071 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(c0,2,1) at malloc+0xa23 sys/kern/kern_malloc.c:331 ifq_init(ffff800000b3c260,ffff800000b3c000,0) at ifq_init+0x6f priq_alloc sys/net/ifq.c:671 [inline] ifq_init(ffff800000b3c260,ffff800000b3c000,0) at ifq_init+0x6f sys/net/ifq.c:202 if_attach_common(ffff800000b3c000) at if_attach_common+0xaf sys/net/if.c:617 if_attach(ffff800000b3c000) at if_attach+0x19 sys/net/if.c:540 tun_create(ffffffff824f9dd0,d9,800) at tun_create+0x1d3 sys/net/if_tun.c:241 if_clone_create(ffff800017b5cb00,0) at if_clone_create+0xa0 sys/net/if.c:1221 tapopen(5dd9,1,2000,ffff8000ffff29f8) at tapopen+0xd1 sys/net/if_tun.c:342 spec_open(ffff800017b5cbe8) at spec_open+0x3ea sys/kern/spec_vnops.c:158 VOP_OPEN(fffffd802f4aeaa8,1,fffffd803f7c6780,ffff8000ffff29f8) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:154 vn_open(ffff800017b5ce38,201,80) at vn_open+0x4eb sys/kern/vfs_vnops.c:186 doopenat(ffff8000ffff29f8,ffffff9c,200001c0,200,80,ffff800017b5d030) at doopenat+0x28b sys/kern/vfs_syscalls.c:1157 syscall(ffff800017b5d0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 end trace frame: 0xffff800017b5d130, count: 0 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 0xffff800000b9da00 size 0xc0 previous type devbuf (0xd != 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(c0,2,1) at malloc+0xa23 sys/kern/kern_malloc.c:331 ifq_init(ffff800000b3c260,ffff800000b3c000,0) at ifq_init+0x6f priq_alloc sys/net/ifq.c:671 [inline] ifq_init(ffff800000b3c260,ffff800000b3c000,0) at ifq_init+0x6f sys/net/ifq.c:202 if_attach_common(ffff800000b3c000) at if_attach_common+0xaf sys/net/if.c:617 if_attach(ffff800000b3c000) at if_attach+0x19 sys/net/if.c:540 tun_create(ffffffff824f9dd0,d9,800) at tun_create+0x1d3 sys/net/if_tun.c:241 if_clone_create(ffff800017b5cb00,0) at if_clone_create+0xa0 sys/net/if.c:1221 tapopen(5dd9,1,2000,ffff8000ffff29f8) at tapopen+0xd1 sys/net/if_tun.c:342 spec_open(ffff800017b5cbe8) at spec_open+0x3ea sys/kern/spec_vnops.c:158 VOP_OPEN(fffffd802f4aeaa8,1,fffffd803f7c6780,ffff8000ffff29f8) at VOP_OPEN+0x6a sys/kern/vfs_vops.c:154 vn_open(ffff800017b5ce38,201,80) at vn_open+0x4eb sys/kern/vfs_vnops.c:186 doopenat(ffff8000ffff29f8,ffffff9c,200001c0,200,80,ffff800017b5d030) at doopenat+0x28b sys/kern/vfs_syscalls.c:1157 syscall(ffff800017b5d0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:555 Xsyscall(0,0,ffffffffffffffa0,0,3,ac1f3c39010) at Xsyscall+0x128 end of kernel end trace frame: 0xac408ce53d0, count: -15 ddb> show registers rdi 0xffffffff81e06467 db_enter+0x17 rsi 0x43e6 __ALIGN_SIZE+0x33e6 rbp 0xffff800017b5c7f0 rbx 0xffff800017b5c8a0 rdx 0x43e7 __ALIGN_SIZE+0x33e7 rcx 0xffff800014919000 rax 0xffff800014919000 r8 0xffff800017b5c7b0 r9 0x1 r10 0xffff800000a56b00 r11 0x205e44f73dfc1e16 r12 0x3000000008 r13 0xffff800017b5c800 r14 0x100 r15 0x1 rip 0xffffffff81e06468 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800017b5c7e0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=321221 stat=onproc flags process=0 proc=4000000 pri=80, usrpri=80, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff2780,0xffffffff825a3380 process=0xffff8000148a2d98 user=0xffff800017b58000, vmspace=0xfffffd803f013440 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 26071 348508 8367 0 2 0 syz-executor.1 *26071 321221 8367 0 7 0x4000000 syz-executor.1 33077 439238 16371 0 3 0x2 biowait syz-executor.0 8367 156333 16371 0 3 0x82 nanosleep syz-executor.1 35062 11272 0 0 3 0x14200 acct acct 21605 66056 0 0 3 0x14200 bored sosplice 16371 493359 85085 0 3 0x82 thrsleep syz-fuzzer 16371 341247 85085 0 3 0x4000082 nanosleep syz-fuzzer 16371 63339 85085 0 3 0x4000082 thrsleep syz-fuzzer 16371 84711 85085 0 3 0x4000082 thrsleep syz-fuzzer 16371 427920 85085 0 3 0x4000082 kqread syz-fuzzer 16371 359071 85085 0 3 0x4000082 thrsleep syz-fuzzer 16371 23035 85085 0 3 0x4000082 thrsleep syz-fuzzer 85085 475267 57101 0 3 0x10008a pause ksh 57101 46057 28699 0 3 0x92 select sshd 56042 331427 1 0 3 0x100083 ttyin getty 28699 238667 1 0 3 0x80 select sshd 59948 337748 87455 73 3 0x100090 kqread syslogd 87455 199676 1 0 3 0x100082 netio syslogd 43088 454142 1 77 3 0x100090 poll dhclient 2372 260173 1 0 3 0x80 poll dhclient 78186 102103 0 0 2 0x14200 zerothread 43391 387436 0 0 3 0x14200 aiodoned aiodoned 31202 347966 0 0 3 0x14200 syncer update 31562 251260 0 0 3 0x14200 cleaner cleaner 15369 278326 0 0 3 0x14200 reaper reaper 47622 363459 0 0 3 0x14200 pgdaemon pagedaemon 97473 486353 0 0 3 0x14200 bored crynlk 29891 207209 0 0 3 0x14200 bored crypto 1210 108459 0 0 3 0x40014200 acpi0 acpi0 26478 504876 0 0 3 0x14200 bored softnet 19781 37517 0 0 3 0x14200 bored systqmp 81335 129483 0 0 3 0x14200 bored systq 27691 147583 0 0 3 0x40014200 bored softclock 55053 22369 0 0 3 0x40014200 idle0 68927 390354 0 0 3 0x14200 bored smr 1 417915 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 9571 6390K 7663K 78643K 22669 0 0 pcb 13 10K 12K 78643K 589 0 0 rtable 85 7K 9K 78643K 2090 0 0 ifaddr 76 15K 18K 78643K 481 0 0 counters 19 16K 16K 78643K 19 0 0 ioctlops 0 0K 2K 78643K 202 0 0 iov 0 0K 32K 78643K 817 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1217 76K 77K 78643K 6173 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 55 0 0 VM map 17 4K 4K 78643K 28 0 0 sem 12 0K 1K 78643K 589 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1793 195K 288K 78643K 12645 0 0 file desc 5 13K 25K 78643K 3071 0 0 sigio 0 0K 0K 78643K 43 0 0 proc 49 38K 55K 78643K 1624 0 0 subproc 32 2K 2K 78643K 442 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 235 0 0 in_multi 11 0K 2K 78643K 428 0 0 ether_multi 1 0K 0K 78643K 34 0 0 mrt 0 0K 0K 78643K 33 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 96 424K 424K 78643K 96 0 0 exec 0 0K 1K 78643K 851 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 142 153K 153K 78643K 10048 0 0 UVM aobj 130 4K 4K 78643K 147 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 565 0 0 NDP 20 0K 1K 78643K 163 0 0 temp 226 3544K 4193K 78643K 81211 0 0 kqueue 0 0K 0K 78643K 38 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 81 0 77 1 0 1 1 0 8 0 rtpcb 80 336 0 333 1 0 1 1 0 8 0 rtentry 112 416 0 390 2 0 2 2 0 8 0 unpcb 120 1668 0 1659 2 1 1 2 0 8 0 syncache 264 14 0 14 6 6 0 1 0 8 0 tcpqe 32 87 0 87 2 2 0 1 0 8 0 tcpcb 544 1119 0 1115 8 7 1 2 0 8 0 ipq 40 27 0 27 12 11 1 1 0 8 1 ipqe 40 414 0 414 12 11 1 1 0 8 1 inpcb 280 4857 0 4850 40 38 2 13 0 8 1 rttmr 72 9 0 9 6 6 0 1 0 8 0 ip6q 72 1 0 1 1 1 0 1 0 8 0 nd6 48 57 0 57 4 3 1 1 0 8 1 pkpcb 40 4 0 4 1 1 0 1 0 8 0 swfcl 56 2 0 0 1 0 1 1 0 8 0 ppxss 1128 42 0 42 18 17 1 1 0 8 1 art_heap8 4096 37 0 36 19 18 1 3 0 8 0 art_heap4 256 2015 0 1885 44 31 13 17 0 8 3 art_table 32 2052 0 1921 5 2 3 3 0 8 1 art_node 16 415 0 391 1 0 1 1 0 8 0 sysvmsgpl 40 44 0 29 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 585 0 575 1 0 1 1 0 8 0 shmpl 112 145 0 17 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 6098 0 4705 46 0 46 46 0 8 0 ffsino 240 6098 0 4705 83 0 83 83 0 8 0 nchpl 144 11535 0 11103 60 41 19 60 0 8 0 uvmvnodes 72 7397 0 0 135 0 135 135 0 8 0 vnodes 208 7397 0 0 390 0 390 390 0 8 0 namei 1024 42606 0 42605 4 3 1 1 0 8 0 vcpupl 1984 16 0 1 2 0 2 2 0 8 0 vmpool 520 26 0 11 1 0 1 1 0 8 0 scsiplug 64 5 0 5 3 3 0 1 0 8 0 scxspl 192 44179 0 44177 29 28 1 7 0 8 0 plimitpl 152 281 0 274 1 0 1 1 0 8 0 sigapl 432 3170 0 3157 2 0 2 2 0 8 0 futexpl 56 87751 0 87751 4 3 1 1 0 8 1 knotepl 112 2688 0 2669 5 4 1 2 0 8 0 kqueuepl 104 3586 0 3584 1 0 1 1 0 8 0 pipepl 112 3000 0 2981 11 10 1 2 0 8 0 fdescpl 424 3171 0 3157 2 0 2 2 0 8 0 filepl 120 34351 0 34253 31 27 4 11 0 8 1 lockfpl 104 1101 0 1099 1 0 1 1 0 8 0 lockfspl 48 381 0 379 1 0 1 1 0 8 0 sessionpl 112 41 0 31 1 0 1 1 0 8 0 pgrppl 48 87 0 77 1 0 1 1 0 8 0 ucredpl 96 5886 0 5878 1 0 1 1 0 8 0 zombiepl 144 3157 0 3157 1 0 1 1 0 8 1 processpl 864 3187 0 3157 4 0 4 4 0 8 0 procpl 632 8153 0 8116 19 15 4 5 0 8 0 sosppl 128 27 0 27 9 9 0 1 0 8 0 sockpl 384 7049 0 7030 59 55 4 21 0 8 1 mcl64k 65536 1622 0 1622 148 123 25 33 0 8 25 mcl16k 16384 50 0 50 22 21 1 1 0 8 1 mcl12k 12288 103 0 103 18 18 0 1 0 8 0 mcl9k 9216 45 0 45 22 22 0 1 0 8 0 mcl8k 8192 179 0 179 14 13 1 1 0 8 1 mcl4k 4096 404 0 404 8 7 1 1 0 8 1 mcl2k2 2112 35 0 35 15 15 0 1 0 8 0 mcl2k 2048 72451 0 72402 19 12 7 15 0 8 0 mtagpl 80 150 0 148 8 7 1 1 0 8 0 mbufpl 256 143425 0 143357 124 106 18 26 0 8 8 bufpl 256 19732 0 12336 467 4 463 463 0 8 0 anonpl 16 449514 0 432845 262 175 87 98 0 62 7 amapchunkpl 152 21840 0 21706 87 80 7 17 0 158 0 amappl16 192 19231 0 18209 220 162 58 64 0 8 5 amappl15 184 405 0 403 3 2 1 1 0 8 0 amappl14 176 978 0 974 1 0 1 1 0 8 0 amappl13 168 58 0 58 6 6 0 1 0 8 0 amappl12 160 307 0 304 1 0 1 1 0 8 0 amappl11 152 395 0 384 1 0 1 1 0 8 0 amappl10 144 419 0 416 2 1 1 1 0 8 0 amappl9 136 1402 0 1395 1 0 1 1 0 8 0 amappl8 128 922 0 882 2 0 2 2 0 8 0 amappl7 120 536 0 527 1 0 1 1 0 8 0 amappl6 112 359 0 348 1 0 1 1 0 8 0 amappl5 104 631 0 620 1 0 1 1 0 8 0 amappl4 96 3032 0 3002 1 0 1 1 0 8 0 amappl3 88 1026 0 1018 1 0 1 1 0 8 0 amappl2 80 23340 0 23272 3 1 2 3 0 8 0 amappl1 72 72409 0 72003 26 17 9 20 0 8 0 amappl 80 8778 0 8726 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 64 146 0 17 3 0 3 3 0 8 0 uaddrrnd 24 3197 0 3157 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3197 0 3157 1 0 1 1 0 8 0 vmmpekpl 168 28210 0 28180 2 0 2 2 0 8 0 vmmpepl 168 403544 0 401422 431 298 133 138 0 357 32 vmsppl 272 3170 0 3157 8 7 1 2 0 8 0 pdppl 4096 6400 0 6351 9 2 7 7 0 8 0 pvpl 32 1187064 0 1167268 549 346 203 334 0 265 26 pmappl 200 3196 0 3168 2 0 2 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 982 0 356 19 0 19 19 0 8 0