panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND * 12691 76798 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(fffffd8067b9eda0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002172dc70,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8079328130,40287401,ffff80002172dc70,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8067ba1db0,40287401,ffff80002172dc70,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002172dd80,ffff80002172ddd0) at sys_ioctl+0x4ac syscall(ffff80002172de50) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc6966512170, 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(fffffd8067b9eda0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002172dc70,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8079328130,40287401,ffff80002172dc70,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8067ba1db0,40287401,ffff80002172dc70,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002172dd80,ffff80002172ddd0) at sys_ioctl+0x4ac syscall(ffff80002172de50) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc6966512170, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002172d6b0 rbx 0xffff80002172d6c0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff820e50f5 kprintf+0x155 r9 0x1 r10 0xc15c8dacfead3373 r11 0xc25bd15891eb2f74 r12 0x3000000008 r13 0xffff80002172d760 r14 0x100 r15 0x1 rip 0xffffffff81ab85c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002172d6a0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=12691 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=52, nice=20 forw=0xffffffffffffffff, list=0xffff8000216717a0,0xffff800021671270 process=0xffff8000216993f0 user=0xffff800021728000, 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 76798 74644 67609 0 2 0 syz-executor.1 *76798 12691 67609 0 7 0x4000000 syz-executor.1 76798 26882 67609 0 3 0x4000080 fsleep syz-executor.1 67609 417950 39701 0 2 0x482 syz-executor.1 29411 128331 39701 0 2 0x482 syz-executor.0 39701 192343 54687 0 3 0x82 thrsleep syz-fuzzer 39701 220341 54687 0 3 0x4000082 thrsleep syz-fuzzer 39701 169416 54687 0 3 0x4000082 thrsleep syz-fuzzer 39701 25518 54687 0 3 0x4000082 thrsleep syz-fuzzer 39701 139697 54687 0 3 0x4000082 thrsleep syz-fuzzer 39701 211375 54687 0 3 0x4000082 kqread syz-fuzzer 39701 354636 54687 0 3 0x4000082 thrsleep syz-fuzzer 54687 140275 70056 0 3 0x10008a sigsusp ksh 70056 118261 74943 0 3 0x92 select sshd 92532 33209 1 0 3 0x100083 ttyin getty 74943 46582 1 0 3 0x80 select sshd 43254 364148 45412 73 3 0x100090 kqread syslogd 45412 90002 1 0 3 0x100082 netio syslogd 72283 39269 1 77 3 0x100090 poll dhclient 45395 173704 1 0 3 0x80 poll dhclient 11348 367029 0 0 3 0x14200 bored smr 68693 254209 0 0 2 0x14200 zerothread 12584 423518 0 0 3 0x14200 aiodoned aiodoned 43594 128121 0 0 3 0x14200 syncer update 90780 391316 0 0 3 0x14200 cleaner cleaner 11519 193534 0 0 3 0x14200 reaper reaper 53487 484509 0 0 3 0x14200 pgdaemon pagedaemon 13115 277758 0 0 3 0x14200 bored crynlk 52471 355785 0 0 3 0x14200 bored crypto 5886 231387 0 0 3 0x14200 bored viomb 50938 452224 0 0 3 0x40014200 acpi0 acpi0 31080 502948 0 0 3 0x14200 bored softnet 98277 248251 0 0 3 0x14200 bored systqmp 14366 102315 0 0 3 0x14200 bored systq 76238 68482 0 0 3 0x40014200 bored softclock 22701 71972 0 0 3 0x40014200 idle0 1 273782 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 9466 6342K 6342K 78643K 10556 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 189 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 1216 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 3 0K 0K 78643K 4 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 37 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 119 25K 26K 78643K 702 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 61 3963K 4027K 78643K 1796 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 32 726 0 726 2 0 2 2 0 8 2 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 semupl 112 1 0 0 1 0 1 1 0 8 0 semapl 112 1 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1419 0 23 88 0 88 88 0 8 0 ffsino 240 1419 0 23 83 0 83 83 0 8 0 nchpl 144 1641 0 40 60 0 60 60 0 8 0 uvmvnodes 72 1462 0 0 27 0 27 27 0 8 0 vnodes 224 1462 0 0 86 0 86 86 0 8 0 namei 1024 3991 0 3991 2 1 1 1 0 8 1 scxspl 216 4696 0 4696 10 2 8 8 0 8 8 plimitpl 152 16 0 7 1 0 1 1 0 8 0 sigapl 424 224 0 195 4 0 4 4 0 8 0 futexpl 56 35 0 34 1 0 1 1 0 8 0 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 5 0 3 1 0 1 1 0 8 0 pipepl 304 69 0 58 1 0 1 1 0 8 0 fdescpl 432 209 0 195 2 0 2 2 0 8 0 filepl 120 977 0 875 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 144 195 0 194 2 1 1 1 0 8 0 processpl 1016 224 0 194 5 0 5 5 0 8 1 procpl 672 234 0 196 4 0 4 4 0 8 0 sockpl 432 74 0 57 4 1 3 3 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 172740 0 172677 73 43 30 35 0 8 21 mtagpl 96 2 0 2 1 1 0 1 0 8 0 mbufpl 256 187758 0 187617 33 19 14 19 0 8 5 bufpl 280 3246 0 169 220 0 220 220 0 8 0 anonpl 24 37779 0 20414 108 2 106 106 0 188 0 amapchunkpl 152 1194 0 828 17 0 17 17 0 158 2 amappl16 200 836 0 101 39 0 39 39 0 8 0 amappl15 192 3 0 2 1 0 1 1 0 8 0 amappl14 184 23 0 18 1 0 1 1 0 8 0 amappl13 176 25 0 22 1 0 1 1 0 8 0 amappl12 168 7 0 6 2 1 1 1 0 8 0 amappl11 160 51 0 39 1 0 1 1 0 8 0 amappl10 152 14 0 8 1 0 1 1 0 8 0 amappl9 144 259 0 259 1 1 0 1 0 8 0 amappl8 136 126 0 94 2 0 2 2 0 8 0 amappl7 128 216 0 209 1 0 1 1 0 8 0 amappl6 120 62 0 51 1 0 1 1 0 8 0 amappl5 112 387 0 373 1 0 1 1 0 8 0 amappl4 104 235 0 214 1 0 1 1 0 8 0 amappl3 96 112 0 103 1 0 1 1 0 8 0 amappl2 88 907 0 842 3 1 2 3 0 8 0 amappl1 80 13803 0 13351 28 16 12 20 0 8 1 amappl 88 477 0 404 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 24 209 0 195 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 209 0 195 1 0 1 1 0 8 0 vmmpekpl 168 5782 0 5760 2 0 2 2 0 8 0 vmmpepl 168 33465 0 31597 124 16 108 108 0 357 25 vmsppl 272 208 0 195 2 0 2 2 0 8 1 rwobjpl 24 9250 0 7852 14 4 10 10 0 8 1 pdppl 4096 424 0 390 58 18 40 40 0 8 6 pvpl 32 127471 0 107212 172 3 169 169 0 265 3 pmappl 200 208 0 195 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 365 0 84 9 0 9 9 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(fffffd8067b9eda0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002172dc70,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8079328130,40287401,ffff80002172dc70,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8067ba1db0,40287401,ffff80002172dc70,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002172dd80,ffff80002172ddd0) at sys_ioctl+0x4ac syscall(ffff80002172de50) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc6966512170, 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(fffffd8067b9eda0) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002172dc70,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8079328130,40287401,ffff80002172dc70,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8067ba1db0,40287401,ffff80002172dc70,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002172dd80,ffff80002172ddd0) at sys_ioctl+0x4ac syscall(ffff80002172de50) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xc6966512170, count: -9