panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *516893 12013 32767 0x10 0x4000000 1K syz-executor.1 463768 20864 0 0x2 0x4000000 0 syz-fuzzer db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6f9788) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000234c2150,3,ffff8000ffff4540) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8077d6c2f0,40287401,ffff8000234c2150,3,fffffd807f7b7a80,ffff8000ffff4540) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8065621e60,40287401,ffff8000234c2150,ffff8000ffff4540) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4540,ffff8000234c2260,ffff8000234c22b0) at sys_ioctl+0x4b0 syscall(ffff8000234c2330) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c2330) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3263ad3f630, 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(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6f9788) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000234c2150,3,ffff8000ffff4540) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8077d6c2f0,40287401,ffff8000234c2150,3,fffffd807f7b7a80,ffff8000ffff4540) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8065621e60,40287401,ffff8000234c2150,ffff8000ffff4540) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4540,ffff8000234c2260,ffff8000234c22b0) at sys_ioctl+0x4b0 syscall(ffff8000234c2330) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c2330) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3263ad3f630, count: -9 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000234c1b90 rbx 0xffff8000234c1ba0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81ea78f5 kprintf+0x145 r9 0x1 r10 0xc095ebe4e1eb4e29 r11 0xd54ef9123c11932e r12 0x3000000008 r13 0xffff8000234c1c40 r14 0x100 r15 0x1 rip 0xffffffff8184d248 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000234c1b80 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=516893 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=55, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff42a0,0xffffffff828cbbd0 process=0xffff8000ffff2a50 user=0xffff8000234bd000, vmspace=0xfffffd807effa2e0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 12013 442091 79371 32767 2 0x10 syz-executor.1 *12013 516893 79371 32767 7 0x4000010 syz-executor.1 79371 367851 17864 32767 3 0x90 nanoslp syz-executor.1 17864 445985 20864 0 3 0x82 wait syz-executor.1 82888 521436 64402 32767 2 0x10 syz-executor.0 64402 447043 20864 0 3 0x82 wait syz-executor.0 20864 216883 45455 0 3 0x82 thrsleep syz-fuzzer 20864 372144 45455 0 3 0x4000082 nanoslp syz-fuzzer 20864 378980 45455 0 3 0x4000082 thrsleep syz-fuzzer 20864 252881 45455 0 3 0x4000082 kqread syz-fuzzer 20864 523779 45455 0 3 0x4000082 thrsleep syz-fuzzer 20864 229550 45455 0 3 0x4000082 thrsleep syz-fuzzer 20864 463768 45455 0 7 0x4000002 syz-fuzzer 20864 458260 45455 0 3 0x4000082 thrsleep syz-fuzzer 45455 399249 37740 0 3 0x10008a sigsusp ksh 37740 441223 55481 0 3 0x92 select sshd 66347 504423 1 0 3 0x100083 ttyin getty 55481 200809 1 0 3 0x80 select sshd 42827 93099 95861 73 3 0x100090 kqread syslogd 95861 415926 1 0 3 0x100082 netio syslogd 1192 120268 1 77 3 0x100090 poll dhclient 86432 216826 1 0 3 0x80 poll dhclient 55828 206041 0 0 3 0x14200 bored smr 6396 285207 0 0 2 0x14200 zerothread 31729 425347 0 0 3 0x14200 aiodoned aiodoned 68185 33493 0 0 3 0x14200 syncer update 1264 159501 0 0 3 0x14200 cleaner cleaner 17803 318950 0 0 3 0x14200 reaper reaper 59802 118211 0 0 3 0x14200 pgdaemon pagedaemon 76054 292856 0 0 3 0x14200 bored crynlk 79310 260609 0 0 3 0x14200 bored crypto 10613 305554 0 0 3 0x14200 bored viomb 46949 284100 0 0 3 0x40014200 acpi0 acpi0 74035 156333 0 0 3 0x40014200 idle1 9193 309552 0 0 3 0x14200 bored softnet 30913 121490 0 0 3 0x14200 bored systqmp 77247 219623 0 0 3 0x14200 bored systq 60471 285495 0 0 3 0x40014200 bored softclock 69776 172321 0 0 3 0x40014200 idle0 1 191857 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 12013 (syz-executor.1) thread 0xffff8000ffff4540 (516893) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828cdd98) #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 9478 6349K 6349K 78643K 10568 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 191 0 ifaddr 39 10K 10K 78643K 39 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 2K 78643K 15 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 76K 78643K 1221 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 10 1K 1K 78643K 15 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 7 21K 33K 78643K 56 0 proc 48 50K 70K 78643K 365 0 subproc 34 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 159 27K 28K 78643K 810 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 68 3973K 4037K 78643K 1847 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 21 0 19 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 37 0 29 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 459 0 459 1 0 1 1 0 8 1 tcpcb 736 14 0 6 1 0 1 1 0 8 0 inpcb 304 36 0 29 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 7 0 7 1 0 1 1 0 8 1 semapl 112 8 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1435 0 40 88 0 88 88 0 8 0 ffsino 272 1435 0 40 94 0 94 94 0 8 0 nchpl 144 1682 0 86 60 0 60 60 0 8 0 uvmvnodes 72 1478 0 0 27 0 27 27 0 8 0 vnodes 224 1478 0 0 87 0 87 87 0 8 0 namei 1024 4080 0 4080 2 1 1 1 0 8 1 percpumem 16 33 0 0 1 0 1 1 0 8 0 scxspl 216 4884 0 4884 10 2 8 8 0 8 8 plimitpl 152 18 0 8 1 0 1 1 0 8 0 sigapl 424 244 0 212 4 0 4 4 0 8 0 futexpl 56 264 0 264 1 0 1 1 0 8 1 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 19 0 17 1 0 1 1 0 8 0 pipepl 336 69 0 58 1 0 1 1 0 8 0 fdescpl 496 228 0 212 3 0 3 3 0 8 0 filepl 152 1049 0 946 6 1 5 5 0 8 1 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 69 0 60 1 0 1 1 0 8 0 zombiepl 144 212 0 212 2 1 1 1 0 8 1 processpl 1080 244 0 212 5 2 3 3 0 8 0 procpl 672 282 0 242 4 0 4 4 0 8 0 sockpl 432 94 0 77 4 1 3 3 0 8 1 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 179 0 0 22 0 22 22 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 192 0 0 12 0 12 12 0 8 0 bufpl 280 3270 0 173 222 0 222 222 0 8 0 anonpl 24 46031 0 21614 150 2 148 148 0 186 0 amapchunkpl 152 1535 0 955 25 1 24 24 0 158 0 amappl16 200 1109 0 145 51 0 51 51 0 8 0 amappl15 192 1 0 0 1 0 1 1 0 8 0 amappl14 184 23 0 19 1 0 1 1 0 8 0 amappl13 176 42 0 37 1 0 1 1 0 8 0 amappl12 168 7 0 3 2 1 1 1 0 8 0 amappl11 160 51 0 39 1 0 1 1 0 8 0 amappl10 152 30 0 24 1 0 1 1 0 8 0 amappl9 144 82 0 80 1 0 1 1 0 8 0 amappl8 136 146 0 105 2 0 2 2 0 8 0 amappl7 128 218 0 210 1 0 1 1 0 8 0 amappl6 120 74 0 61 1 0 1 1 0 8 0 amappl5 112 754 0 739 1 0 1 1 0 8 0 amappl4 104 249 0 222 1 0 1 1 0 8 0 amappl3 96 133 0 119 1 0 1 1 0 8 0 amappl2 88 1048 0 980 3 1 2 3 0 8 0 amappl1 80 14367 0 13897 26 13 13 20 0 8 2 amappl 88 571 0 467 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 24 228 0 212 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 228 0 212 1 0 1 1 0 8 0 vmmpekpl 168 5897 0 5879 1 0 1 1 0 8 0 vmmpepl 168 37176 0 34862 152 9 143 143 0 357 41 vmsppl 368 227 0 212 2 0 2 2 0 8 0 rwobjpl 56 10165 0 8486 31 5 26 26 0 8 1 pdppl 4096 463 0 424 61 16 45 45 0 8 6 pvpl 32 140359 0 112864 225 0 225 225 0 265 3 pmappl 232 227 0 212 2 0 2 2 0 8 1 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 304 0 19 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff826feff0) 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(ffffffff828cdb90) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) at __mp_lock+0x122 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc upageflttrap(ffff80002126c720,c002d301e0) at upageflttrap+0x77 sys/arch/amd64/amd64/trap.c:180 usertrap(ffff80002126c720) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:406 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0xc000872c78, count: 5 ddb{0}> trace x86_ipi_db(ffffffff826feff0) 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(ffffffff828cdb90) at __mp_lock+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) at __mp_lock+0x122 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc upageflttrap(ffff80002126c720,c002d301e0) at upageflttrap+0x77 sys/arch/amd64/amd64/trap.c:180 usertrap(ffff80002126c720) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:406 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0xc000872c78, 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(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6f9788) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000234c2150,3,ffff8000ffff4540) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8077d6c2f0,40287401,ffff8000234c2150,3,fffffd807f7b7a80,ffff8000ffff4540) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8065621e60,40287401,ffff8000234c2150,ffff8000ffff4540) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4540,ffff8000234c2260,ffff8000234c22b0) at sys_ioctl+0x4b0 syscall(ffff8000234c2330) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c2330) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3263ad3f630, count: 6 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e6f9788) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000234c2150,3,ffff8000ffff4540) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd8077d6c2f0,40287401,ffff8000234c2150,3,fffffd807f7b7a80,ffff8000ffff4540) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8065621e60,40287401,ffff8000234c2150,ffff8000ffff4540) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4540,ffff8000234c2260,ffff8000234c22b0) at sys_ioctl+0x4b0 syscall(ffff8000234c2330) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c2330) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x3263ad3f630, count: -9