panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *225516 22943 0 0 0x4000000 0 syz-executor.1 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(fffffd80679ca6b0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021f29b10,3,ffff8000216717a0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6754b0,40287401,ffff800021f29b10,3,fffffd807f7b75a0,ffff8000216717a0) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80677e0c48,40287401,ffff800021f29b10,ffff8000216717a0) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000216717a0,ffff800021f29c20,ffff800021f29c70) at sys_ioctl+0x4ac syscall(ffff800021f29cf0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa6758176610, 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(fffffd80679ca6b0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021f29b10,3,ffff8000216717a0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6754b0,40287401,ffff800021f29b10,3,fffffd807f7b75a0,ffff8000216717a0) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80677e0c48,40287401,ffff800021f29b10,ffff8000216717a0) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000216717a0,ffff800021f29c20,ffff800021f29c70) at sys_ioctl+0x4ac syscall(ffff800021f29cf0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa6758176610, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff800021f29550 rbx 0xffff800021f29560 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff820e50f5 kprintf+0x155 r9 0x1 r10 0xe8dbc3060d1a464d r11 0x1abb0d2db2d79756 r12 0x3000000008 r13 0xffff800021f29600 r14 0x100 r15 0x1 rip 0xffffffff81ab85c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800021f29540 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=225516 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800021670a80,0xffff800021670550 process=0xffff80002165d408 user=0xffff800021f24000, vmspace=0xfffffd807effc990 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 22943 445072 99210 0 2 0 syz-executor.1 *22943 225516 99210 0 7 0x4000000 syz-executor.1 22943 413339 99210 0 3 0x4000080 fsleep syz-executor.1 99210 343226 32541 0 2 0x482 syz-executor.1 30666 287999 32541 0 2 0x2 syz-executor.0 32541 183093 30954 0 3 0x82 thrsleep syz-fuzzer 32541 355893 30954 0 2 0x4000482 syz-fuzzer 32541 18896 30954 0 3 0x4000082 thrsleep syz-fuzzer 32541 490014 30954 0 3 0x4000082 thrsleep syz-fuzzer 32541 121088 30954 0 3 0x4000082 thrsleep syz-fuzzer 32541 98153 30954 0 3 0x4000082 thrsleep syz-fuzzer 32541 42596 30954 0 3 0x4000082 kqread syz-fuzzer 30954 135771 78997 0 3 0x10008a sigsusp ksh 78997 134455 34402 0 3 0x92 select sshd 2622 89596 1 0 3 0x100083 ttyin getty 34402 40116 1 0 3 0x80 select sshd 3640 207038 6124 73 3 0x100090 kqread syslogd 6124 367272 1 0 3 0x100082 netio syslogd 675 429200 1 77 3 0x100090 poll dhclient 91990 86316 1 0 3 0x80 poll dhclient 2659 144364 0 0 3 0x14200 bored smr 29078 176714 0 0 2 0x14200 zerothread 97723 142050 0 0 3 0x14200 aiodoned aiodoned 18581 237651 0 0 3 0x14200 syncer update 12140 217605 0 0 3 0x14200 cleaner cleaner 44242 391123 0 0 3 0x14200 reaper reaper 95418 69191 0 0 3 0x14200 pgdaemon pagedaemon 48397 358163 0 0 3 0x14200 bored crynlk 18599 54272 0 0 3 0x14200 bored crypto 68386 292449 0 0 3 0x14200 bored viomb 4848 523983 0 0 3 0x40014200 acpi0 acpi0 53615 175249 0 0 2 0x14200 softnet 23395 399463 0 0 3 0x14200 bored systqmp 17790 15261 0 0 3 0x14200 bored systq 8881 231993 0 0 2 0x40014200 softclock 24876 253899 0 0 3 0x40014200 idle0 1 240727 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 9473 6345K 6475K 78643K 10576 0 pcb 13 8K 8K 78643K 17 0 rtable 105 3K 3K 78643K 192 0 ifaddr 44 10K 10K 78643K 44 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 2K 78643K 15 0 iov 0 0K 8K 78643K 2 0 mount 1 1K 1K 78643K 1 0 vnodes 1218 77K 77K 78643K 1226 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 7 0K 0K 78643K 7 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 62 0 proc 47 38K 63K 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 in_multi 33 2K 2K 78643K 33 0 ether_multi 1 0K 0K 78643K 1 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 113 23K 24K 78643K 755 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 10 0K 0K 78643K 10 0 temp 66 3963K 4027K 78643K 1856 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 32 627 0 627 1 0 1 1 0 8 1 tcpcb 736 10 0 6 1 0 1 1 0 8 0 inpcb 304 44 0 37 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 semapl 112 5 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1448 0 52 88 0 88 88 0 8 0 ffsino 240 1448 0 52 83 0 83 83 0 8 0 nchpl 144 1693 0 96 60 0 60 60 0 8 0 uvmvnodes 72 1493 0 0 28 0 28 28 0 8 0 vnodes 224 1493 0 0 88 0 88 88 0 8 0 namei 1024 4107 0 4107 2 1 1 1 0 8 1 scxspl 216 4666 0 4666 3 2 1 2 0 8 1 plimitpl 152 16 0 7 1 0 1 1 0 8 0 sigapl 424 249 0 220 4 0 4 4 0 8 0 futexpl 56 285 0 284 1 0 1 1 0 8 0 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 31 0 29 1 0 1 1 0 8 0 pipepl 304 69 0 58 1 0 1 1 0 8 0 fdescpl 432 234 0 220 2 0 2 2 0 8 0 filepl 120 1045 0 942 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 60 0 53 1 0 1 1 0 8 0 zombiepl 144 220 0 220 2 1 1 1 0 8 1 processpl 1016 249 0 220 5 0 5 5 0 8 1 procpl 672 284 0 247 4 0 4 4 0 8 0 sockpl 432 86 0 69 4 1 3 3 0 8 1 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl9k 9216 1 0 1 1 0 1 1 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 176213 0 176143 36 19 17 26 0 8 7 mtagpl 96 2 0 2 1 1 0 1 0 8 0 mbufpl 256 190689 0 190596 14 0 14 14 0 8 5 bufpl 280 3272 0 169 222 0 222 222 0 8 0 anonpl 24 57337 0 38707 139 2 137 137 0 188 21 amapchunkpl 152 1364 0 1012 16 0 16 16 0 158 1 amappl16 200 1952 0 1128 57 0 57 57 0 8 13 amappl15 192 15 0 13 1 0 1 1 0 8 0 amappl14 184 25 0 18 1 0 1 1 0 8 0 amappl13 176 25 0 22 1 0 1 1 0 8 0 amappl12 168 14 0 12 1 0 1 1 0 8 0 amappl11 160 53 0 42 1 0 1 1 0 8 0 amappl10 152 9 0 5 1 0 1 1 0 8 0 amappl9 144 280 0 280 1 1 0 1 0 8 0 amappl8 136 158 0 122 2 0 2 2 0 8 0 amappl7 128 218 0 209 1 0 1 1 0 8 0 amappl6 120 60 0 53 1 0 1 1 0 8 0 amappl5 112 379 0 364 1 0 1 1 0 8 0 amappl4 104 235 0 215 1 0 1 1 0 8 0 amappl3 96 110 0 103 1 0 1 1 0 8 0 amappl2 88 1103 0 1040 3 1 2 3 0 8 0 amappl1 80 14594 0 14133 28 11 17 21 0 8 6 amappl 88 529 0 459 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 24 234 0 220 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 234 0 220 1 0 1 1 0 8 0 vmmpekpl 168 5855 0 5832 2 0 2 2 0 8 0 vmmpepl 168 37701 0 35733 128 9 119 119 0 357 31 vmsppl 272 233 0 220 2 0 2 2 0 8 1 rwobjpl 24 10988 0 9496 13 2 11 11 0 8 0 pdppl 4096 474 0 440 53 13 40 40 0 8 6 pvpl 32 157802 0 136280 214 0 214 214 0 265 35 pmappl 200 233 0 220 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 305 0 36 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(fffffd80679ca6b0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021f29b10,3,ffff8000216717a0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6754b0,40287401,ffff800021f29b10,3,fffffd807f7b75a0,ffff8000216717a0) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80677e0c48,40287401,ffff800021f29b10,ffff8000216717a0) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000216717a0,ffff800021f29c20,ffff800021f29c70) at sys_ioctl+0x4ac syscall(ffff800021f29cf0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa6758176610, 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(fffffd80679ca6b0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021f29b10,3,ffff8000216717a0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6754b0,40287401,ffff800021f29b10,3,fffffd807f7b75a0,ffff8000216717a0) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80677e0c48,40287401,ffff800021f29b10,ffff8000216717a0) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000216717a0,ffff800021f29c20,ffff800021f29c70) at sys_ioctl+0x4ac syscall(ffff800021f29cf0) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa6758176610, count: -9