panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 11981 6899 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(fffffd807da38088) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800022746e70,3,ffff800021670d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eaf12f0,40287401,ffff800022746e70,3,fffffd807f7b7a80,ffff800021670d20) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80678b4bd0,40287401,ffff800022746e70,ffff800021670d20) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021670d20,ffff800022746f80,ffff800022746fd0) at sys_ioctl+0x4ac syscall(ffff800022747050) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x717a5794e30, 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(fffffd807da38088) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800022746e70,3,ffff800021670d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eaf12f0,40287401,ffff800022746e70,3,fffffd807f7b7a80,ffff800021670d20) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80678b4bd0,40287401,ffff800022746e70,ffff800021670d20) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021670d20,ffff800022746f80,ffff800022746fd0) at sys_ioctl+0x4ac syscall(ffff800022747050) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x717a5794e30, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff8000227468b0 rbx 0xffff8000227468c0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff820e50f5 kprintf+0x155 r9 0x1 r10 0x2d3bb43063d4dcda r11 0x4e799a9c32e1c0aa r12 0x3000000008 r13 0xffff800022746960 r14 0x100 r15 0x1 rip 0xffffffff81ab85c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000227468a0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.0) pid=11981 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=55, nice=20 forw=0xffffffffffffffff, list=0xffff800021671500,0xffffffff827ebf10 process=0xffff80002165d010 user=0xffff800022742000, vmspace=0xfffffd807effc550 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 6899 385202 34919 0 2 0 syz-executor.0 * 6899 11981 34919 0 7 0x4000000 syz-executor.0 98488 127529 88088 0 2 0x482 syz-executor.1 34919 28951 88088 0 2 0x482 syz-executor.0 88088 275046 14858 0 3 0x82 thrsleep syz-fuzzer 88088 454719 14858 0 3 0x4000082 thrsleep syz-fuzzer 88088 306927 14858 0 3 0x4000082 kqread syz-fuzzer 88088 335796 14858 0 3 0x4000082 thrsleep syz-fuzzer 88088 225824 14858 0 3 0x4000082 thrsleep syz-fuzzer 88088 249730 14858 0 3 0x4000082 thrsleep syz-fuzzer 88088 507491 14858 0 3 0x4000082 thrsleep syz-fuzzer 14858 151193 72319 0 3 0x10008a sigsusp ksh 72319 16643 64010 0 3 0x92 select sshd 93510 129312 1 0 3 0x100083 ttyin getty 64010 325122 1 0 3 0x80 select sshd 65320 485362 42699 73 2 0x100090 syslogd 42699 477323 1 0 3 0x100082 netio syslogd 40247 295856 1 77 3 0x100090 poll dhclient 67598 387008 1 0 3 0x80 poll dhclient 9785 359373 0 0 3 0x14200 bored smr 39779 305097 0 0 2 0x14200 zerothread 71705 300810 0 0 3 0x14200 aiodoned aiodoned 95676 260027 0 0 3 0x14200 syncer update 18899 115421 0 0 3 0x14200 cleaner cleaner 62394 102482 0 0 3 0x14200 reaper reaper 49144 44908 0 0 3 0x14200 pgdaemon pagedaemon 42776 252285 0 0 3 0x14200 bored crynlk 22223 185925 0 0 3 0x14200 bored crypto 12627 467445 0 0 3 0x14200 bored viomb 2066 226113 0 0 3 0x40014200 acpi0 acpi0 22689 160073 0 0 3 0x14200 bored softnet 12395 496374 0 0 3 0x14200 bored systqmp 48040 249679 0 0 3 0x14200 bored systq 50579 50181 0 0 3 0x40014200 bored softclock 14465 394078 0 0 3 0x40014200 idle0 1 105893 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 6345K 78643K 10564 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 191 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 2K 78643K 2 0 mount 1 1K 1K 78643K 1 0 vnodes 1215 76K 76K 78643K 1222 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 2 0K 0K 78643K 2 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 38 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 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 112 22K 23K 78643K 703 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 65 3963K 4027K 78643K 1803 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 1207 0 1207 2 1 1 2 0 8 1 tcpcb 736 10 0 6 1 0 1 1 0 8 0 inpcb 304 32 0 25 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 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1422 0 26 88 0 88 88 0 8 0 ffsino 240 1422 0 26 83 0 83 83 0 8 0 nchpl 144 1644 0 46 60 0 60 60 0 8 0 uvmvnodes 72 1465 0 0 27 0 27 27 0 8 0 vnodes 224 1465 0 0 87 0 87 87 0 8 0 namei 1024 4004 0 4004 2 1 1 1 0 8 1 scxspl 216 4709 0 4709 9 1 8 8 0 8 8 plimitpl 152 16 0 8 1 0 1 1 0 8 0 sigapl 424 225 0 196 4 0 4 4 0 8 0 futexpl 56 45 0 45 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 432 210 0 196 2 0 2 2 0 8 0 filepl 120 978 0 877 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 144 196 0 195 2 1 1 1 0 8 0 processpl 1016 225 0 195 5 0 5 5 0 8 1 procpl 672 235 0 198 4 0 4 4 0 8 0 sockpl 432 74 0 57 4 1 3 3 0 8 1 mcl64k 65536 3 0 3 1 0 1 1 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 164850 0 164772 70 52 18 35 0 8 7 mtagpl 96 2 0 2 1 1 0 1 0 8 0 mbufpl 256 179394 0 179293 26 12 14 19 0 8 5 bufpl 280 3248 0 169 220 0 220 220 0 8 0 anonpl 24 38647 0 20411 113 2 111 111 0 188 0 amapchunkpl 152 1189 0 797 19 1 18 18 0 158 2 amappl16 200 870 0 105 41 0 41 41 0 8 0 amappl15 192 3 0 2 1 0 1 1 0 8 0 amappl14 184 22 0 18 1 0 1 1 0 8 0 amappl13 176 26 0 23 1 0 1 1 0 8 0 amappl12 168 21 0 17 1 0 1 1 0 8 0 amappl11 160 53 0 41 1 0 1 1 0 8 0 amappl10 152 4 0 1 1 0 1 1 0 8 0 amappl9 144 273 0 273 1 1 0 1 0 8 0 amappl8 136 115 0 88 2 0 2 2 0 8 0 amappl7 128 215 0 209 1 0 1 1 0 8 0 amappl6 120 59 0 52 1 0 1 1 0 8 0 amappl5 112 360 0 346 1 0 1 1 0 8 0 amappl4 104 239 0 215 1 0 1 1 0 8 0 amappl3 96 108 0 101 1 0 1 1 0 8 0 amappl2 88 914 0 845 3 1 2 3 0 8 0 amappl1 80 13982 0 13544 27 15 12 20 0 8 1 amappl 88 485 0 411 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 24 210 0 196 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 210 0 196 1 0 1 1 0 8 0 vmmpekpl 168 5800 0 5780 1 0 1 1 0 8 0 vmmpepl 168 33757 0 31876 121 11 110 110 0 357 23 vmsppl 272 209 0 196 2 0 2 2 0 8 1 rwobjpl 24 9322 0 7913 14 4 10 10 0 8 1 pdppl 4096 426 0 392 58 18 40 40 0 8 6 pvpl 32 128986 0 107874 179 3 176 176 0 265 2 pmappl 200 209 0 196 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 356 0 86 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(fffffd807da38088) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800022746e70,3,ffff800021670d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eaf12f0,40287401,ffff800022746e70,3,fffffd807f7b7a80,ffff800021670d20) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80678b4bd0,40287401,ffff800022746e70,ffff800021670d20) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021670d20,ffff800022746f80,ffff800022746fd0) at sys_ioctl+0x4ac syscall(ffff800022747050) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x717a5794e30, 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(fffffd807da38088) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800022746e70,3,ffff800021670d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806eaf12f0,40287401,ffff800022746e70,3,fffffd807f7b7a80,ffff800021670d20) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80678b4bd0,40287401,ffff800022746e70,ffff800021670d20) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021670d20,ffff800022746f80,ffff800022746fd0) at sys_ioctl+0x4ac syscall(ffff800022747050) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x717a5794e30, count: -9