panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *473810 51439 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(fffffd8078398408) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002273d4a0,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e718590,40287401,ffff80002273d4a0,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8069ab89f0,40287401,ffff80002273d4a0,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002273d5b0,ffff80002273d600) at sys_ioctl+0x4ac syscall(ffff80002273d680) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2c325d9090, 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(fffffd8078398408) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002273d4a0,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e718590,40287401,ffff80002273d4a0,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8069ab89f0,40287401,ffff80002273d4a0,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002273d5b0,ffff80002273d600) at sys_ioctl+0x4ac syscall(ffff80002273d680) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2c325d9090, count: -9 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002273cee0 rbx 0xffff80002273cef0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff820e50f5 kprintf+0x155 r9 0x1 r10 0x3fb66af48c3d40cb r11 0x91d4f11ab18724f6 r12 0x3000000008 r13 0xffff80002273cf90 r14 0x100 r15 0x1 rip 0xffffffff81ab85c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002273ced0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=473810 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=66, nice=20 forw=0xffffffffffffffff, list=0xffff8000216707e0,0xffffffff827ebf10 process=0xffff800021698c00 user=0xffff800022738000, vmspace=0xfffffd807effc000 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 51439 319348 3197 0 2 0 syz-executor.1 *51439 473810 3197 0 7 0x4000000 syz-executor.1 3197 97355 79754 0 2 0x482 syz-executor.1 70900 161677 79754 0 2 0x2 syz-executor.0 79754 253889 1008 0 3 0x82 thrsleep syz-fuzzer 79754 190130 1008 0 2 0x4000482 syz-fuzzer 79754 424510 1008 0 3 0x4000082 thrsleep syz-fuzzer 79754 245414 1008 0 3 0x4000082 kqread syz-fuzzer 79754 196646 1008 0 3 0x4000082 thrsleep syz-fuzzer 79754 461660 1008 0 3 0x4000082 thrsleep syz-fuzzer 79754 191584 1008 0 3 0x4000082 thrsleep syz-fuzzer 79754 87626 1008 0 3 0x4000082 thrsleep syz-fuzzer 1008 326498 70473 0 3 0x10008a sigsusp ksh 70473 272512 95733 0 3 0x92 select sshd 18869 45551 1 0 3 0x100083 ttyin getty 95733 421540 1 0 3 0x80 select sshd 78341 216297 58453 73 3 0x100090 kqread syslogd 58453 173658 1 0 3 0x100082 netio syslogd 89977 234346 1 77 3 0x100090 poll dhclient 10920 220293 1 0 3 0x80 poll dhclient 84336 223709 0 0 2 0x14200 smr 93896 65222 0 0 2 0x14200 zerothread 7911 293977 0 0 3 0x14200 aiodoned aiodoned 39578 148123 0 0 3 0x14200 syncer update 51176 346011 0 0 3 0x14200 cleaner cleaner 91481 128849 0 0 3 0x14200 reaper reaper 18910 382917 0 0 3 0x14200 pgdaemon pagedaemon 67046 348067 0 0 3 0x14200 bored crynlk 44854 252892 0 0 3 0x14200 bored crypto 22752 328551 0 0 3 0x14200 bored viomb 91082 503007 0 0 3 0x40014200 acpi0 acpi0 78094 232603 0 0 3 0x14200 bored softnet 16030 331014 0 0 3 0x14200 bored systqmp 92389 400737 0 0 3 0x14200 bored systq 52098 168214 0 0 2 0x40014200 softclock 93981 206635 0 0 3 0x40014200 idle0 1 35680 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 6600K 78643K 10586 0 pcb 13 8K 8K 78643K 20 0 rtable 105 3K 3K 78643K 191 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 77K 78643K 1228 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 57 0 proc 47 38K 54K 78643K 369 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 mrt 0 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 319 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 747 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 1848 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 29 0 21 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 481 0 481 1 0 1 1 0 8 1 tcpcb 736 15 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 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1447 0 52 88 0 88 88 0 8 0 ffsino 240 1447 0 52 83 0 83 83 0 8 0 nchpl 144 1696 0 99 60 0 60 60 0 8 0 uvmvnodes 72 1496 0 0 28 0 28 28 0 8 0 vnodes 224 1496 0 0 88 0 88 88 0 8 0 namei 1024 4222 0 4221 2 1 1 1 0 8 0 scxspl 216 4660 0 4660 2 1 1 2 0 8 1 plimitpl 152 16 0 8 1 0 1 1 0 8 0 sigapl 424 244 0 215 4 0 4 4 0 8 0 futexpl 56 216 0 216 1 0 1 1 0 8 1 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 24 0 22 1 0 1 1 0 8 0 pipepl 304 69 0 58 1 0 1 1 0 8 0 fdescpl 432 229 0 215 2 0 2 2 0 8 0 filepl 120 1047 0 946 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 144 215 0 215 2 1 1 1 0 8 1 processpl 1016 244 0 215 5 0 5 5 0 8 1 procpl 672 274 0 237 4 0 4 4 0 8 0 sockpl 432 92 0 75 4 1 3 3 0 8 1 mcl4k 4096 8 0 8 1 1 0 1 0 8 0 mcl2k 2048 173593 0 173527 21 4 17 17 0 8 8 mtagpl 96 4 0 2 2 1 1 1 0 8 0 mbufpl 256 187406 0 187280 12 1 11 11 0 8 0 bufpl 280 3271 0 171 222 0 222 222 0 8 0 anonpl 24 40268 0 21803 114 2 112 112 0 188 0 amapchunkpl 152 1280 0 913 17 1 16 16 0 158 1 amappl16 200 968 0 163 43 0 43 43 0 8 0 amappl15 192 1 0 0 1 0 1 1 0 8 0 amappl14 184 22 0 18 1 0 1 1 0 8 0 amappl13 176 36 0 32 1 0 1 1 0 8 0 amappl12 168 11 0 8 2 1 1 1 0 8 0 amappl11 160 45 0 34 1 0 1 1 0 8 0 amappl10 152 16 0 12 1 0 1 1 0 8 0 amappl9 144 262 0 261 2 1 1 1 0 8 0 amappl8 136 121 0 88 2 0 2 2 0 8 0 amappl7 128 216 0 209 1 0 1 1 0 8 0 amappl6 120 77 0 69 1 0 1 1 0 8 0 amappl5 112 405 0 391 1 0 1 1 0 8 0 amappl4 104 237 0 215 1 0 1 1 0 8 0 amappl3 96 129 0 118 1 0 1 1 0 8 0 amappl2 88 1058 0 996 3 1 2 3 0 8 0 amappl1 80 14382 0 13944 27 11 16 20 0 8 5 amappl 88 518 0 447 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 24 229 0 215 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 229 0 215 1 0 1 1 0 8 0 vmmpekpl 168 5853 0 5832 1 0 1 1 0 8 0 vmmpepl 168 36210 0 34278 128 8 120 120 0 357 36 vmsppl 272 228 0 215 2 0 2 2 0 8 1 rwobjpl 24 9833 0 8382 12 2 10 10 0 8 1 pdppl 4096 464 0 430 53 13 40 40 0 8 6 pvpl 32 134706 0 113333 176 0 176 176 0 265 1 pmappl 200 228 0 215 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 287 0 22 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(fffffd8078398408) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002273d4a0,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e718590,40287401,ffff80002273d4a0,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8069ab89f0,40287401,ffff80002273d4a0,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002273d5b0,ffff80002273d600) at sys_ioctl+0x4ac syscall(ffff80002273d680) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2c325d9090, 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(fffffd8078398408) at vrele+0x187 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff80002273d4a0,3,ffff800021671500) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e718590,40287401,ffff80002273d4a0,3,fffffd807f7b7b40,ffff800021671500) at VOP_IOCTL+0x91 sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8069ab89f0,40287401,ffff80002273d4a0,ffff800021671500) at vn_ioctl+0xb5 sys/kern/vfs_vnops.c:531 sys_ioctl(ffff800021671500,ffff80002273d5b0,ffff80002273d600) at sys_ioctl+0x4ac syscall(ffff80002273d680) at syscall+0x507 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2c325d9090, count: -9