panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *298886 93518 0 0 0x4000000 0 syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8243627a) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e1e34e8) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002170aed0,3,ffff800021671a40) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eb05130,40287401,ffff80002170aed0,3,fffffd807f7b7cc0,ffff800021671a40) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80679fc9f0,40287401,ffff80002170aed0,ffff800021671a40) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671a40,ffff80002170afe0,ffff80002170b030) at sys_ioctl+0x4ac syscall(ffff80002170b0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x73f377f99d0, count: 6 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 vrele: v_writecount != 0 ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8243627a) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e1e34e8) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002170aed0,3,ffff800021671a40) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eb05130,40287401,ffff80002170aed0,3,fffffd807f7b7cc0,ffff800021671a40) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80679fc9f0,40287401,ffff80002170aed0,ffff800021671a40) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671a40,ffff80002170afe0,ffff80002170b030) at sys_ioctl+0x4ac syscall(ffff80002170b0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x73f377f99d0, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002170a910 rbx 0xffff80002170a920 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff820e50f5 kprintf+0x155 r9 0x1 r10 0xfbade56f62098227 r11 0x9dc4a3a5d43b472 r12 0x3000000008 r13 0xffff80002170a9c0 r14 0x100 r15 0x1 rip 0xffffffff81ab85c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002170a900 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.0) pid=298886 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=57, nice=20 forw=0xffffffffffffffff, list=0xffff800021671500,0xffffffff827ebf10 process=0xffff800021698808 user=0xffff800021706000, vmspace=0xfffffd807effccc0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 93518 402183 84847 0 2 0 syz-executor.0 *93518 298886 84847 0 7 0x4000000 syz-executor.0 84847 242066 1753 0 2 0x482 syz-executor.0 15489 514192 1753 0 2 0x2 syz-executor.1 1753 320685 57079 0 3 0x82 thrsleep syz-fuzzer 1753 230354 57079 0 2 0x4000482 syz-fuzzer 1753 160313 57079 0 3 0x4000082 kqread syz-fuzzer 1753 321602 57079 0 3 0x4000082 thrsleep syz-fuzzer 1753 480182 57079 0 3 0x4000082 thrsleep syz-fuzzer 1753 284477 57079 0 3 0x4000082 thrsleep syz-fuzzer 1753 116560 57079 0 3 0x4000082 thrsleep syz-fuzzer 57079 219568 4845 0 3 0x10008a sigsusp ksh 4845 89822 41812 0 3 0x92 select sshd 88079 445839 1 0 3 0x100083 ttyin getty 41812 437143 1 0 3 0x80 select sshd 68772 186155 74007 73 2 0x100090 syslogd 74007 249571 1 0 3 0x100082 netio syslogd 11853 191666 1 77 3 0x100090 poll dhclient 61932 204206 1 0 3 0x80 poll dhclient 20080 77241 0 0 2 0x14200 smr 25264 225135 0 0 2 0x14200 zerothread 95908 185913 0 0 3 0x14200 aiodoned aiodoned 64048 462013 0 0 3 0x14200 syncer update 66685 218952 0 0 3 0x14200 cleaner cleaner 50814 49505 0 0 3 0x14200 reaper reaper 81906 134875 0 0 3 0x14200 pgdaemon pagedaemon 73519 73617 0 0 3 0x14200 bored crynlk 13168 414494 0 0 3 0x14200 bored crypto 88036 296862 0 0 3 0x14200 bored viomb 6649 421742 0 0 3 0x40014200 acpi0 acpi0 82834 82411 0 0 3 0x14200 bored softnet 14674 367169 0 0 3 0x14200 bored systqmp 606 453980 0 0 3 0x14200 bored systq 34259 26372 0 0 2 0x40014200 softclock 30044 182738 0 0 3 0x40014200 idle0 1 359212 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 9476 6472K 6472K 78643K 10569 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 190 0 ifaddr 39 10K 10K 78643K 39 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 2K 78643K 15 0 mount 1 1K 1K 78643K 1 0 vnodes 1217 77K 77K 78643K 1223 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 1K 78643K 2 0 VM map 2 0K 0K 78643K 2 0 sem 6 0K 0K 78643K 10 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 40 0 proc 47 38K 54K 78643K 364 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 2 0 in_multi 33 2K 2K 78643K 36 0 ether_multi 1 0K 0K 78643K 2 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 37 175K 175K 78643K 37 0 exec 0 0K 2K 78643K 317 0 pagedep 1 8K 8K 78643K 1 0 inodedep 1 32K 32K 78643K 1 0 newblk 1 0K 0K 78643K 1 0 VM swap 7 26K 26K 78643K 7 0 UVM amap 116 23K 24K 78643K 711 0 UVM aobj 3 2K 2K 78643K 3 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 9 0K 0K 78643K 9 0 temp 60 3963K 4027K 78643K 1804 0 kqueue 3 4K 4K 78643K 3 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 6 0 0 1 0 1 1 0 8 0 rtpcb 120 19 0 17 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 23 0 15 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 1163 0 1163 1 0 1 1 0 8 1 tcpcb 736 12 0 6 1 0 1 1 0 8 0 inpcb 304 34 0 27 1 0 1 1 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 kcovpl 48 2 0 0 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 188 0 0 12 0 12 12 0 8 0 art_table 32 189 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 semupl 112 6 0 6 1 0 1 1 0 8 1 semapl 112 4 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1421 0 25 88 0 88 88 0 8 0 ffsino 240 1421 0 25 83 0 83 83 0 8 0 nchpl 144 1650 0 52 60 0 60 60 0 8 0 uvmvnodes 72 1466 0 0 27 0 27 27 0 8 0 vnodes 224 1466 0 0 87 0 87 87 0 8 0 namei 1024 4022 0 4022 2 1 1 1 0 8 1 scxspl 216 4712 0 4712 9 1 8 8 0 8 8 plimitpl 152 16 0 8 1 0 1 1 0 8 0 sigapl 424 227 0 198 4 0 4 4 0 8 0 futexpl 56 103 0 103 1 0 1 1 0 8 1 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 6 0 4 1 0 1 1 0 8 0 pipepl 304 69 0 58 1 0 1 1 0 8 0 fdescpl 432 212 0 198 2 0 2 2 0 8 0 filepl 120 997 0 896 4 0 4 4 0 8 0 lockfpl 104 5 0 4 1 0 1 1 0 8 0 lockfspl 48 3 0 2 1 0 1 1 0 8 0 sessionpl 144 17 0 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 57 0 50 1 0 1 1 0 8 0 zombiepl 144 198 0 198 2 1 1 1 0 8 1 processpl 1016 227 0 198 5 0 5 5 0 8 1 procpl 672 239 0 203 4 0 4 4 0 8 0 sockpl 432 76 0 59 4 1 3 3 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 166865 0 166803 49 31 18 27 0 8 8 mtagpl 96 4 0 2 2 1 1 1 0 8 0 mbufpl 256 180981 0 180837 16 3 13 14 0 8 3 bufpl 280 3247 0 169 220 0 220 220 0 8 0 anonpl 24 39335 0 21286 112 2 110 110 0 188 0 amapchunkpl 152 1263 0 909 16 0 16 16 0 158 1 amappl16 200 902 0 112 42 0 42 42 0 8 0 amappl15 192 5 0 2 1 0 1 1 0 8 0 amappl14 184 32 0 27 1 0 1 1 0 8 0 amappl13 176 24 0 22 1 0 1 1 0 8 0 amappl12 168 8 0 6 1 0 1 1 0 8 0 amappl11 160 46 0 35 1 0 1 1 0 8 0 amappl10 152 11 0 6 1 0 1 1 0 8 0 amappl9 144 277 0 276 2 1 1 1 0 8 0 amappl8 136 113 0 84 2 0 2 2 0 8 0 amappl7 128 214 0 207 1 0 1 1 0 8 0 amappl6 120 60 0 52 1 0 1 1 0 8 0 amappl5 112 358 0 344 1 0 1 1 0 8 0 amappl4 104 241 0 218 1 0 1 1 0 8 0 amappl3 96 110 0 103 1 0 1 1 0 8 0 amappl2 88 937 0 872 3 1 2 3 0 8 0 amappl1 80 13918 0 13472 27 14 13 20 0 8 2 amappl 88 484 0 413 2 0 2 2 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 64 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 212 0 198 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 212 0 198 1 0 1 1 0 8 0 vmmpekpl 168 5798 0 5778 1 0 1 1 0 8 0 vmmpepl 168 33853 0 31942 128 9 119 119 0 357 35 vmsppl 272 211 0 198 2 0 2 2 0 8 1 rwobjpl 24 9365 0 7927 13 3 10 10 0 8 1 pdppl 4096 430 0 396 56 16 40 40 0 8 6 pvpl 32 130979 0 110054 174 0 174 174 0 265 3 pmappl 200 211 0 198 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 322 0 54 8 0 8 8 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8243627a) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e1e34e8) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002170aed0,3,ffff800021671a40) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eb05130,40287401,ffff80002170aed0,3,fffffd807f7b7cc0,ffff800021671a40) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80679fc9f0,40287401,ffff80002170aed0,ffff800021671a40) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671a40,ffff80002170afe0,ffff80002170b030) at sys_ioctl+0x4ac syscall(ffff80002170b0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x73f377f99d0, count: -9 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8243627a) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e1e34e8) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002170aed0,3,ffff800021671a40) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eb05130,40287401,ffff80002170aed0,3,fffffd807f7b7cc0,ffff800021671a40) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80679fc9f0,40287401,ffff80002170aed0,ffff800021671a40) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671a40,ffff80002170afe0,ffff80002170b030) at sys_ioctl+0x4ac syscall(ffff80002170b0b0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x73f377f99d0, count: -9