panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 45932 80313 32767 0x10 0 0 syz-executor.0 *315007 80313 32767 0x10 0x4000000 1K syz-executor.0 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(fffffd806e5b7248) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256da8b0,3,ffff8000ffff4d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806ee5d3d0,40287401,ffff8000256da8b0,3,fffffd807f7b78a0,ffff8000ffff4d20) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8057565dc8,40287401,ffff8000256da8b0,ffff8000ffff4d20) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4d20,ffff8000256da9c0,ffff8000256daa10) at sys_ioctl+0x4b0 syscall(ffff8000256daa90) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256daa90) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa128604bbe0, 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(fffffd806e5b7248) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256da8b0,3,ffff8000ffff4d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806ee5d3d0,40287401,ffff8000256da8b0,3,fffffd807f7b78a0,ffff8000ffff4d20) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8057565dc8,40287401,ffff8000256da8b0,ffff8000ffff4d20) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4d20,ffff8000256da9c0,ffff8000256daa10) at sys_ioctl+0x4b0 syscall(ffff8000256daa90) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256daa90) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa128604bbe0, count: -9 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000256da2f0 rbx 0xffff8000256da300 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81ea78f5 kprintf+0x145 r9 0x1 r10 0x2bf85fb6e2878d30 r11 0x9c20771fe1c88b68 r12 0x3000000008 r13 0xffff8000256da3a0 r14 0x100 r15 0x1 rip 0xffffffff8184d248 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000256da2e0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=315007 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff4fc0,0xffffffff828cbbd0 process=0xffff8000ffff21e0 user=0xffff8000256d5000, vmspace=0xfffffd807effacf0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 80313 45932 58492 32767 7 0x10 syz-executor.0 *80313 315007 58492 32767 7 0x4000010 syz-executor.0 44649 123316 65298 32767 3 0x10 biowait syz-executor.1 65298 381355 13251 0 3 0x82 wait syz-executor.1 58492 286842 3733 32767 3 0x90 nanoslp syz-executor.0 3733 81063 13251 0 3 0x82 wait syz-executor.0 13251 470281 73785 0 3 0x82 thrsleep syz-fuzzer 13251 417767 73785 0 3 0x4000082 nanoslp syz-fuzzer 13251 100013 73785 0 3 0x4000082 thrsleep syz-fuzzer 13251 444208 73785 0 3 0x4000082 kqread syz-fuzzer 13251 429772 73785 0 3 0x4000082 nanoslp syz-fuzzer 13251 296475 73785 0 3 0x4000082 thrsleep syz-fuzzer 13251 231339 73785 0 3 0x4000082 thrsleep syz-fuzzer 13251 183492 73785 0 3 0x4000082 thrsleep syz-fuzzer 73785 245412 86526 0 3 0x10008a sigsusp ksh 86526 116359 28439 0 3 0x92 select sshd 48016 251628 1 0 3 0x100083 ttyin getty 28439 359825 1 0 3 0x80 select sshd 17528 185045 56268 73 3 0x100090 kqread syslogd 56268 413529 1 0 3 0x100082 netio syslogd 9243 350202 1 77 3 0x100090 poll dhclient 57334 397288 1 0 3 0x80 poll dhclient 88135 80111 0 0 3 0x14200 bored smr 90958 296432 0 0 3 0x14200 pgzero zerothread 3058 140790 0 0 3 0x14200 aiodoned aiodoned 65158 377103 0 0 3 0x14200 syncer update 20017 434692 0 0 3 0x14200 cleaner cleaner 60248 83005 0 0 3 0x14200 reaper reaper 64103 144546 0 0 3 0x14200 pgdaemon pagedaemon 17233 313954 0 0 3 0x14200 bored crynlk 55503 343483 0 0 3 0x14200 bored crypto 10844 315762 0 0 3 0x14200 bored viomb 84157 23239 0 0 3 0x40014200 acpi0 acpi0 63999 119756 0 0 3 0x40014200 idle1 7267 396343 0 0 3 0x14200 bored softnet 50110 445257 0 0 3 0x14200 bored systqmp 14425 117199 0 0 3 0x14200 bored systq 36604 286851 0 0 3 0x40014200 bored softclock 92751 251908 0 0 3 0x40014200 idle0 1 365948 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 80313 (syz-executor.0) thread 0xffff8000ffff4d20 (315007) 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 Process 44649 (syz-executor.1) thread 0xffff8000ffff42a0 (123316) exclusive rrwlock inode r = 0 (0xfffffd80573b4d58) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 rw_enter+0x443 sys/kern/kern_rwlock.c:312 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:463 #3 ufs_ihashins+0x45 sys/ufs/ufs/ufs_ihash.c:140 #4 ffs_vget+0x135 sys/ufs/ffs/ffs_vfsops.c:1350 #5 ffs_inode_alloc+0x1e1 sys/ufs/ffs/ffs_alloc.c:394 #6 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162 #7 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:459 #8 domkdirat+0x121 sys/kern/vfs_syscalls.c:3064 #9 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #9 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 #10 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd806bb4ac58) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 rw_enter+0x443 sys/kern/kern_rwlock.c:312 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:463 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:614 #4 vn_lock+0x6c sys/kern/vfs_vnops.c:575 #5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419 #6 namei+0x5f7 sys/kern/vfs_lookup.c:249 #7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3049 #8 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 #9 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9477 6349K 6349K 78643K 10567 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 189 0 ifaddr 39 10K 10K 78643K 39 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 2K 78643K 54 0 iov 0 0K 0K 78643K 4 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 76K 78643K 1223 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 4 0 VM map 2 1K 1K 78643K 2 0 sem 11 1K 1K 78643K 11 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 7 21K 33K 78643K 10236 0 sigio 0 0K 0K 78643K 3 0 proc 48 50K 70K 78643K 372 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 31 148K 148K 78643K 31 0 exec 0 0K 2K 78643K 321 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 515 62K 62K 78643K 27915 0 UVM aobj 10 2K 2K 78643K 12 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 5 0K 0K 78643K 9 0 temp 101 3981K 4045K 78643K 22236 0 kqueue 3 4K 7K 78643K 13 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 11597 0 11589 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 43 0 43 1 1 0 1 0 8 0 tcpcb 736 10 0 6 1 0 1 1 0 8 0 inpcb 304 485 0 477 5 3 2 2 0 8 1 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 3 0 3 1 1 0 1 0 8 0 semapl 112 9 0 0 1 0 1 1 0 8 0 shmpl 112 9 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 11622 0 10226 88 0 88 88 0 8 0 ffsino 272 11622 0 10226 94 0 94 94 0 8 0 nchpl 144 22101 0 20504 60 0 60 60 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 224 5926 0 0 349 0 349 349 0 8 0 namei 1024 51195 0 51194 2 1 1 1 0 8 0 percpumem 16 33 0 0 1 0 1 1 0 8 0 scxspl 216 66034 0 66033 10 9 1 8 0 8 0 plimitpl 152 17 0 7 1 0 1 1 0 8 0 sigapl 424 10424 0 10392 4 0 4 4 0 8 0 futexpl 56 79104 0 79104 1 0 1 1 0 8 1 knotepl 112 68 0 48 1 0 1 1 0 8 0 kqueuepl 168 10289 0 10284 1 0 1 1 0 8 0 pipepl 336 134 0 123 4 2 2 2 0 8 1 fdescpl 496 10408 0 10392 3 0 3 3 0 8 0 filepl 152 40006 0 39904 7 2 5 5 0 8 1 lockfpl 104 73 0 72 1 0 1 1 0 8 0 lockfspl 48 30 0 29 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 96 105 0 96 1 0 1 1 0 8 0 zombiepl 144 10392 0 10392 2 1 1 1 0 8 1 processpl 1080 10424 0 10392 5 2 3 3 0 8 0 procpl 672 21177 0 21137 4 0 4 4 0 8 0 sockpl 432 12108 0 12091 4 1 3 3 0 8 1 mcl64k 65536 17 0 0 3 0 3 3 0 8 0 mcl16k 16384 8 0 0 1 0 1 1 0 8 0 mcl12k 12288 7 0 0 1 0 1 1 0 8 0 mcl9k 9216 9 0 0 1 0 1 1 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 25 0 0 3 0 3 3 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 253 0 0 25 1 24 25 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 494 0 0 24 0 24 24 0 8 0 bufpl 280 13458 0 7211 447 0 447 447 0 8 0 anonpl 24 742782 0 657836 583 3 580 581 0 186 0 amapchunkpl 152 37152 0 33737 145 0 145 145 0 158 0 amappl16 200 30981 0 28610 127 1 126 126 0 8 1 amappl15 192 5074 0 5070 1 0 1 1 0 8 0 amappl14 184 23 0 19 1 0 1 1 0 8 0 amappl13 176 38 0 34 1 0 1 1 0 8 0 amappl12 168 13 0 10 1 0 1 1 0 8 0 amappl11 160 51 0 39 1 0 1 1 0 8 0 amappl10 152 11 0 7 1 0 1 1 0 8 0 amappl9 144 286 0 286 1 1 0 1 0 8 0 amappl8 136 149 0 108 2 0 2 2 0 8 0 amappl7 128 219 0 210 1 0 1 1 0 8 0 amappl6 120 63 0 51 1 0 1 1 0 8 0 amappl5 112 10599 0 10580 1 0 1 1 0 8 0 amappl4 104 274 0 244 2 1 1 2 0 8 0 amappl3 96 152 0 143 1 0 1 1 0 8 0 amappl2 88 84850 0 84782 3 1 2 3 0 8 0 amappl1 80 308778 0 308292 30 19 11 21 0 8 0 amappl 88 21825 0 21367 11 0 11 11 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 11 0 2 1 0 1 1 0 8 0 uaddrrnd 24 10408 0 10392 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 10408 0 10392 1 0 1 1 0 8 0 vmmpekpl 168 47483 0 47463 3 1 2 2 0 8 0 vmmpepl 168 1327000 0 1322912 298 113 185 290 0 357 3 vmsppl 368 10407 0 10392 2 0 2 2 0 8 0 rwobjpl 56 244906 0 241451 59 9 50 51 0 8 1 pdppl 4096 20823 0 20784 63 22 41 45 0 8 2 pvpl 32 3919459 0 3831384 799 4 795 799 0 265 0 pmappl 232 10407 0 10392 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 332 0 28 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 intr_handler(ffff80002349e6b0,ffff80000006a400) at intr_handler+0x5e sys/arch/amd64/amd64/intr.c:532 Xintr_ioapic_edge17_untramp() at Xintr_ioapic_edge17_untramp+0x18f end of kernel end trace frame: 0x7f7ffffd4c20, 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+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) at __mp_lock+0x122 sys/kern/kern_lock.c:147 intr_handler(ffff80002349e6b0,ffff80000006a400) at intr_handler+0x5e sys/arch/amd64/amd64/intr.c:532 Xintr_ioapic_edge17_untramp() at Xintr_ioapic_edge17_untramp+0x18f end of kernel end trace frame: 0x7f7ffffd4c20, 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(fffffd806e5b7248) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256da8b0,3,ffff8000ffff4d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806ee5d3d0,40287401,ffff8000256da8b0,3,fffffd807f7b78a0,ffff8000ffff4d20) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8057565dc8,40287401,ffff8000256da8b0,ffff8000ffff4d20) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4d20,ffff8000256da9c0,ffff8000256daa10) at sys_ioctl+0x4b0 syscall(ffff8000256daa90) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256daa90) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa128604bbe0, 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(fffffd806e5b7248) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256da8b0,3,ffff8000ffff4d20) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806ee5d3d0,40287401,ffff8000256da8b0,3,fffffd807f7b78a0,ffff8000ffff4d20) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd8057565dc8,40287401,ffff8000256da8b0,ffff8000ffff4d20) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4d20,ffff8000256da9c0,ffff8000256daa10) at sys_ioctl+0x4b0 syscall(ffff8000256daa90) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256daa90) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xa128604bbe0, count: -9