panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 162917 41558 0 0x2 0 0 syz-executor0898 *361815 41558 0 0x2 0x4000000 1K syz-executor0898 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(fffffd806e5c54e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021250740,3,ffff8000ffff7cf0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6f8050,40287401,ffff800021250740,3,fffffd807f7b7b40,ffff8000ffff7cf0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd807b79dc78,40287401,ffff800021250740,ffff8000ffff7cf0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff7cf0,ffff800021250850,ffff8000212508a0) at sys_ioctl+0x4b0 syscall(ffff800021250920) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021250920) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2a22d1d7fd0, 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(fffffd806e5c54e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021250740,3,ffff8000ffff7cf0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6f8050,40287401,ffff800021250740,3,fffffd807f7b7b40,ffff8000ffff7cf0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd807b79dc78,40287401,ffff800021250740,ffff8000ffff7cf0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff7cf0,ffff800021250850,ffff8000212508a0) at sys_ioctl+0x4b0 syscall(ffff800021250920) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021250920) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2a22d1d7fd0, count: -9 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800021250180 rbx 0xffff800021250190 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81ea78f5 kprintf+0x145 r9 0x1 r10 0x24c6537b6a726167 r11 0x4f7add1104960cee r12 0x3000000008 r13 0xffff800021250230 r14 0x100 r15 0x1 rip 0xffffffff8184d248 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800021250170 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor0898) pid=361815 stat=onproc flags process=2 proc=4000000 pri=50, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff67f0,0xffffffff828cbbd0 process=0xffff8000ffff9520 user=0xffff80002124b000, vmspace=0xfffffd806ea45458 estcpu=0, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 41558 162917 26770 0 7 0x2 syz-executor0898 41558 176978 26770 0 3 0x4000082 fsleep syz-executor0898 *41558 361815 26770 0 7 0x4000002 syz-executor0898 26770 206913 69901 0 3 0x10008a sigsusp ksh 69901 65485 27615 0 3 0x92 select sshd 66141 47352 1 0 3 0x100083 ttyin getty 27615 395321 1 0 3 0x80 select sshd 71210 257144 87974 73 3 0x100090 kqread syslogd 87974 206453 1 0 3 0x100082 netio syslogd 34860 478508 1 77 3 0x100090 poll dhclient 88871 444608 1 0 3 0x80 poll dhclient 10406 488320 0 0 3 0x14200 bored smr 96161 496832 0 0 2 0x14200 zerothread 49572 240212 0 0 3 0x14200 aiodoned aiodoned 86001 471820 0 0 3 0x14200 syncer update 63143 34852 0 0 3 0x14200 cleaner cleaner 32942 119743 0 0 3 0x14200 reaper reaper 47710 263905 0 0 3 0x14200 pgdaemon pagedaemon 85920 24403 0 0 3 0x14200 bored crynlk 26557 33589 0 0 3 0x14200 bored crypto 10689 162877 0 0 3 0x14200 bored viomb 71004 328316 0 0 3 0x40014200 acpi0 acpi0 22594 481885 0 0 3 0x40014200 idle1 14040 415138 0 0 3 0x14200 bored softnet 39898 33435 0 0 3 0x14200 bored systqmp 40810 381885 0 0 3 0x14200 bored systq 49451 225234 0 0 3 0x40014200 bored softclock 25224 47189 0 0 3 0x40014200 idle0 1 291222 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 41558 (syz-executor0898) thread 0xffff8000ffff7cf0 (361815) 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 9471 6345K 6345K 78643K 10561 0 pcb 13 8K 8K 78643K 13 0 rtable 61 2K 2K 78643K 117 0 ifaddr 24 7K 7K 78643K 24 0 counters 40 33K 33K 78643K 40 0 ioctlops 0 0K 2K 78643K 13 0 mount 1 1K 1K 78643K 1 0 vnodes 1182 74K 74K 78643K 1187 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 1 0K 0K 78643K 1 0 proc 47 50K 58K 78643K 284 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 11 0K 0K 78643K 11 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 31 148K 148K 78643K 31 0 exec 0 0K 2K 78643K 261 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 34 1K 2K 78643K 512 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 3 0K 0K 78643K 3 0 temp 18 3969K 4033K 78643K 1442 0 kqueue 2 2K 2K 78643K 2 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 2 0 0 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 120 15 0 13 1 0 1 1 0 8 0 rtentry 112 23 0 1 1 0 1 1 0 8 0 unpcb 120 27 0 19 1 0 1 1 0 8 0 syncache 296 5 0 5 2 1 1 1 0 8 1 tcpcb 736 8 0 5 1 0 1 1 0 8 0 inpcb 304 22 0 16 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 96 0 0 6 0 6 6 0 8 0 art_table 32 97 0 0 1 0 1 1 0 8 0 art_node 16 22 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1389 0 15 86 0 86 86 0 8 0 ffsino 272 1389 0 15 92 0 92 92 0 8 0 nchpl 144 1563 0 31 57 0 57 57 0 8 0 uvmvnodes 72 1398 0 0 26 0 26 26 0 8 0 vnodes 224 1398 0 0 83 0 83 83 0 8 0 namei 1024 3497 0 3497 2 1 1 1 0 8 1 percpumem 16 31 0 0 1 0 1 1 0 8 0 scxspl 216 3330 0 3330 2 1 1 2 0 8 1 plimitpl 152 15 0 9 1 0 1 1 0 8 0 sigapl 424 193 0 166 4 0 4 4 0 8 0 futexpl 56 1 0 0 1 0 1 1 0 8 0 knotepl 112 5 0 0 1 0 1 1 0 8 0 kqueuepl 168 1 0 0 1 0 1 1 0 8 0 pipepl 336 57 0 53 2 1 1 1 0 8 0 fdescpl 496 177 0 166 2 0 2 2 0 8 0 filepl 152 827 0 781 2 0 2 2 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 9 1 0 1 1 0 8 0 pgrppl 48 17 0 9 1 0 1 1 0 8 0 ucredpl 96 63 0 56 1 0 1 1 0 8 0 zombiepl 144 166 0 166 2 1 1 1 0 8 1 processpl 1080 193 0 166 3 1 2 3 0 8 0 procpl 672 195 0 166 3 0 3 3 0 8 0 sockpl 432 64 0 48 2 0 2 2 0 8 0 mcl4k 4096 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 80 0 0 10 0 10 10 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 95 0 0 6 0 6 6 0 8 0 bufpl 280 1923 0 104 130 0 130 130 0 8 0 anonpl 24 18196 0 17031 11 3 8 10 0 186 0 amapchunkpl 152 472 0 433 3 1 2 3 0 158 0 amappl16 200 67 0 62 1 0 1 1 0 8 0 amappl15 192 1 0 0 1 0 1 1 0 8 0 amappl14 184 22 0 19 1 0 1 1 0 8 0 amappl13 176 12 0 11 2 1 1 1 0 8 0 amappl12 168 9 0 9 1 1 0 1 0 8 0 amappl11 160 41 0 32 1 0 1 1 0 8 0 amappl10 152 8 0 6 1 0 1 1 0 8 0 amappl9 144 231 0 231 2 1 1 1 0 8 1 amappl8 136 56 0 54 1 0 1 1 0 8 0 amappl7 128 183 0 182 1 0 1 1 0 8 0 amappl6 120 52 0 46 1 0 1 1 0 8 0 amappl5 112 319 0 305 1 0 1 1 0 8 0 amappl4 104 246 0 225 1 0 1 1 0 8 0 amappl3 96 91 0 84 1 0 1 1 0 8 0 amappl2 88 749 0 696 2 0 2 2 0 8 0 amappl1 80 12811 0 12404 16 5 11 16 0 8 0 amappl 88 350 0 330 1 0 1 1 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 24 177 0 166 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 177 0 166 1 0 1 1 0 8 0 vmmpekpl 168 5288 0 5274 1 0 1 1 0 8 0 vmmpepl 168 26505 0 25713 47 11 36 44 0 357 1 vmsppl 368 176 0 166 2 0 2 2 0 8 0 rwobjpl 56 7029 0 6504 12 4 8 12 0 8 0 pdppl 4096 361 0 332 42 13 29 35 0 8 0 pvpl 32 72581 0 69753 31 4 27 27 0 265 2 pmappl 232 176 0 166 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 257 0 17 7 0 7 7 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+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) 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 end of kernel end trace frame: 0x7f7fffff3fc0, count: 9 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+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) 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 end of kernel end trace frame: 0x7f7fffff3fc0, count: -6 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(fffffd806e5c54e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021250740,3,ffff8000ffff7cf0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6f8050,40287401,ffff800021250740,3,fffffd807f7b7b40,ffff8000ffff7cf0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd807b79dc78,40287401,ffff800021250740,ffff8000ffff7cf0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff7cf0,ffff800021250850,ffff8000212508a0) at sys_ioctl+0x4b0 syscall(ffff800021250920) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021250920) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2a22d1d7fd0, 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(fffffd806e5c54e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff800021250740,3,ffff8000ffff7cf0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e6f8050,40287401,ffff800021250740,3,fffffd807f7b7b40,ffff8000ffff7cf0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd807b79dc78,40287401,ffff800021250740,ffff8000ffff7cf0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff7cf0,ffff800021250850,ffff8000212508a0) at sys_ioctl+0x4b0 syscall(ffff800021250920) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021250920) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2a22d1d7fd0, count: -9 ddb{1}>