panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 370553 1690 0 0 0 0 syz-executor.1 *434066 1690 0 0 0x4000000 1K syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6b6410) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000222b7980,3,ffff80002123ca88) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e2c3bb8,40287401,ffff8000222b7980,3,fffffd807f7b7a80,ffff80002123ca88) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8064ff1720,40287401,ffff8000222b7980,ffff80002123ca88) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123ca88,ffff8000222b7a90,ffff8000222b7ae0) at sys_ioctl+0x4b0 syscall(ffff8000222b7b60) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222b7b60) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x4a715df4d50, 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{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic vrele: v_writecount != 0 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6b6410) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000222b7980,3,ffff80002123ca88) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e2c3bb8,40287401,ffff8000222b7980,3,fffffd807f7b7a80,ffff80002123ca88) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8064ff1720,40287401,ffff8000222b7980,ffff80002123ca88) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123ca88,ffff8000222b7a90,ffff8000222b7ae0) at sys_ioctl+0x4b0 syscall(ffff8000222b7b60) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222b7b60) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x4a715df4d50, count: -9 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000222b73c0 rbx 0xffff8000222b73d0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81b81665 kprintf+0x145 r9 0x1 r10 0xf432d3d4b710af55 r11 0x13b0dc824e07b0e r12 0x3000000008 r13 0xffff8000222b7470 r14 0x100 r15 0x1 rip 0xffffffff81e4d228 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000222b73b0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=434066 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=60, nice=20 forw=0xffffffffffffffff, list=0xffff80002123c2a8,0xffffffff828c76b0 process=0xffff800021235960 user=0xffff8000222b2000, vmspace=0xfffffd807eff9450 estcpu=10, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 1690 370553 12572 0 7 0 syz-executor.1 * 1690 434066 12572 0 7 0x4000000 syz-executor.1 12572 294545 52010 0 3 0x82 nanoslp syz-executor.1 25315 430246 52010 0 3 0x82 nanoslp syz-executor.0 52010 331429 81268 0 3 0x82 thrsleep syz-fuzzer 52010 97828 81268 0 3 0x4000082 thrsleep syz-fuzzer 52010 315508 81268 0 3 0x4000082 thrsleep syz-fuzzer 52010 2425 81268 0 3 0x4000082 kqread syz-fuzzer 52010 75073 81268 0 3 0x4000082 thrsleep syz-fuzzer 52010 363666 81268 0 3 0x4000082 thrsleep syz-fuzzer 52010 221018 81268 0 3 0x4000082 thrsleep syz-fuzzer 52010 255612 81268 0 3 0x4000082 thrsleep syz-fuzzer 81268 407746 90849 0 3 0x10008a sigsusp ksh 90849 417793 99144 0 3 0x92 select sshd 17170 373940 1 0 3 0x100083 ttyin getty 99144 461975 1 0 3 0x80 select sshd 54569 33535 88701 74 3 0x100092 bpf pflogd 88701 172495 1 0 3 0x80 netio pflogd 2751 90859 78635 73 3 0x100090 kqread syslogd 78635 53995 1 0 3 0x100082 netio syslogd 88371 30023 1 77 3 0x100090 poll dhclient 82531 263601 1 0 3 0x80 poll dhclient 45448 243075 0 0 3 0x14200 bored smr 41309 289783 0 0 3 0x14200 pgzero zerothread 42022 79377 0 0 3 0x14200 aiodoned aiodoned 98601 413809 0 0 3 0x14200 syncer update 20131 504567 0 0 3 0x14200 cleaner cleaner 31018 110772 0 0 3 0x14200 reaper reaper 47577 80661 0 0 3 0x14200 pgdaemon pagedaemon 19956 118542 0 0 3 0x14200 bored crynlk 3065 478993 0 0 3 0x14200 bored crypto 85884 95376 0 0 3 0x14200 bored viomb 2512 190583 0 0 3 0x40014200 acpi0 acpi0 65472 144502 0 0 3 0x40014200 idle1 63594 291389 0 0 3 0x14200 bored softnet 49561 71851 0 0 3 0x14200 bored systqmp 10013 233391 0 0 3 0x14200 bored systq 13455 362863 0 0 3 0x40014200 bored softclock 70018 266695 0 0 3 0x40014200 idle0 1 456539 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 1690 (syz-executor.1) thread 0xffff80002123ca88 (434066) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828d4128) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 vn_ioctl+0x40 sys/kern/vfs_vnops.c:514 #2 sys_ioctl+0x4b0 #3 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #3 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 #4 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9484 6416K 6674K 78643K 10595 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 199 0 ifaddr 44 10K 10K 78643K 45 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 4K 78643K 1469 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 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 1K 1K 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 53 0 proc 59 63K 83K 78643K 447 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 360 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 165 29K 30K 78643K 879 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 3971K 4035K 78643K 2080 0 kqueue 3 4K 4K 78643K 3 0 SYN cache 2 16K 16K 78643K 2 0 ddb{1}> 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 plcache 128 20 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 25 0 15 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 629 0 629 1 0 1 1 0 8 1 tcpcb 736 12 0 6 1 0 1 1 0 8 0 inpcb 304 41 0 34 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 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 12 0 0 1 0 1 1 0 8 0 pfstkey 112 12 0 0 1 0 1 1 0 8 0 pfstate 320 12 0 0 1 0 1 1 0 8 0 pfrule 1360 21 0 16 2 1 1 2 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 1444 0 40 88 0 88 88 0 8 0 ffsino 272 1444 0 40 95 1 94 94 0 8 0 nchpl 144 1681 0 76 60 0 60 60 0 8 0 uvmvnodes 72 1492 0 0 28 0 28 28 0 8 0 vnodes 224 1492 0 0 88 0 88 88 0 8 0 namei 1024 4353 0 4353 2 1 1 1 0 8 1 percpumem 16 33 0 0 1 0 1 1 0 8 0 scxspl 216 4914 0 4914 5 1 4 4 0 8 4 plimitpl 152 17 0 8 1 0 1 1 0 8 0 sigapl 424 269 0 237 4 0 4 4 0 8 0 futexpl 56 143 0 143 1 0 1 1 0 8 1 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 18 0 16 1 0 1 1 0 8 0 pipepl 336 85 0 74 2 0 2 2 0 8 1 fdescpl 496 253 0 237 3 0 3 3 0 8 0 filepl 152 1164 0 1058 6 1 5 5 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 18 0 7 1 0 1 1 0 8 0 pgrppl 48 18 0 7 1 0 1 1 0 8 0 ucredpl 96 62 0 53 1 0 1 1 0 8 0 zombiepl 144 237 0 236 2 1 1 1 0 8 0 processpl 1080 269 0 236 3 0 3 3 0 8 0 procpl 672 300 0 259 5 1 4 4 0 8 0 sockpl 432 85 0 66 3 0 3 3 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 184 0 0 22 0 22 22 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 224 0 0 14 0 14 14 0 8 0 bufpl 280 3416 0 181 232 0 232 232 0 8 0 anonpl 24 41134 0 24006 107 2 105 105 0 186 0 amapchunkpl 152 1338 0 896 20 0 20 20 0 158 1 amappl16 200 819 0 178 35 0 35 35 0 8 1 amappl15 192 18 0 13 1 0 1 1 0 8 0 amappl14 184 23 0 19 1 0 1 1 0 8 0 amappl13 176 31 0 29 1 0 1 1 0 8 0 amappl12 168 10 0 8 1 0 1 1 0 8 0 amappl11 160 60 0 43 1 0 1 1 0 8 0 amappl10 152 28 0 23 1 0 1 1 0 8 0 amappl9 144 287 0 287 1 1 0 1 0 8 0 amappl8 136 180 0 121 3 0 3 3 0 8 0 amappl7 128 245 0 236 1 0 1 1 0 8 0 amappl6 120 89 0 78 1 0 1 1 0 8 0 amappl5 112 394 0 375 1 0 1 1 0 8 0 amappl4 104 281 0 254 1 0 1 1 0 8 0 amappl3 96 121 0 114 1 0 1 1 0 8 0 amappl2 88 1135 0 1064 3 1 2 3 0 8 0 amappl1 80 15889 0 15414 26 9 17 21 0 8 5 amappl 88 600 0 506 3 0 3 3 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 24 253 0 237 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 253 0 237 1 0 1 1 0 8 0 vmmpekpl 168 6143 0 6115 3 1 2 2 0 8 0 vmmpepl 168 39304 0 37396 120 7 113 113 0 357 24 vmsppl 368 252 0 237 2 0 2 2 0 8 0 rwobjpl 56 10424 0 9037 27 5 22 22 0 8 2 pdppl 4096 513 0 474 60 15 45 45 0 8 6 pvpl 32 144320 0 124005 174 0 174 174 0 265 8 pmappl 232 252 0 237 2 0 2 2 0 8 1 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 308 0 20 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff826d1ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 upageflttrap(ffff8000222b1ca0,4a66f0d69a0) at upageflttrap+0x77 sys/arch/amd64/amd64/trap.c:180 usertrap(ffff8000222b1ca0) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:406 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe9f10, count: 5 ddb{0}> trace x86_ipi_db(ffffffff826d1ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 upageflttrap(ffff8000222b1ca0,4a66f0d69a0) at upageflttrap+0x77 sys/arch/amd64/amd64/trap.c:180 usertrap(ffff8000222b1ca0) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:406 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe9f10, count: -10 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x18: addq $0x8,%rsp db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6b6410) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000222b7980,3,ffff80002123ca88) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e2c3bb8,40287401,ffff8000222b7980,3,fffffd807f7b7a80,ffff80002123ca88) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8064ff1720,40287401,ffff8000222b7980,ffff80002123ca88) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123ca88,ffff8000222b7a90,ffff8000222b7ae0) at sys_ioctl+0x4b0 syscall(ffff8000222b7b60) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222b7b60) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x4a715df4d50, count: 6 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6b6410) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000222b7980,3,ffff80002123ca88) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e2c3bb8,40287401,ffff8000222b7980,3,fffffd807f7b7a80,ffff80002123ca88) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8064ff1720,40287401,ffff8000222b7980,ffff80002123ca88) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123ca88,ffff8000222b7a90,ffff8000222b7ae0) at sys_ioctl+0x4b0 syscall(ffff8000222b7b60) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222b7b60) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x4a715df4d50, count: -9