panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *225146 39245 0 0 0x4000000 0K syz-executor.0 129471 82783 0 0x2 0x480 1 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 vrele(fffffd8063cff8b0) at vrele+0x188 sys/kern/vfs_subr.c:797 diskmapioctl(5a00,c0106477,ffff800023e4d1f0,1,ffff800020b28508) at diskmapioctl+0x2a8 sys/dev/diskmap.c:140 VOP_IOCTL(fffffd806faba648,c0106477,ffff800023e4d1f0,1,fffffd807f7c6960,ffff800020b28508) at VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290 vn_ioctl(fffffd8068033850,c0106477,ffff800023e4d1f0,ffff800020b28508) at vn_ioctl+0xb6 sys/kern/vfs_vnops.c:519 sys_ioctl(ffff800020b28508,ffff800023e4d308,ffff800023e4d370) at sys_ioctl+0x5b8 syscall(ffff800023e4d3e0) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800023e4d3e0) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffff1f,0,3,f23693fb010) at Xsyscall+0x128 end of kernel end trace frame: 0xf26487f4600, 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{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic vrele: v_writecount != 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 vrele(fffffd8063cff8b0) at vrele+0x188 sys/kern/vfs_subr.c:797 diskmapioctl(5a00,c0106477,ffff800023e4d1f0,1,ffff800020b28508) at diskmapioctl+0x2a8 sys/dev/diskmap.c:140 VOP_IOCTL(fffffd806faba648,c0106477,ffff800023e4d1f0,1,fffffd807f7c6960,ffff800020b28508) at VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290 vn_ioctl(fffffd8068033850,c0106477,ffff800023e4d1f0,ffff800020b28508) at vn_ioctl+0xb6 sys/kern/vfs_vnops.c:519 sys_ioctl(ffff800020b28508,ffff800023e4d308,ffff800023e4d370) at sys_ioctl+0x5b8 syscall(ffff800023e4d3e0) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800023e4d3e0) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffff1f,0,3,f23693fb010) at Xsyscall+0x128 end of kernel end trace frame: 0xf26487f4600, count: -9 ddb{0}> show registers rdi 0xffffffff81b7cd57 db_enter+0x17 rsi 0x6745 __ALIGN_SIZE+0x5745 rbp 0xffff800023e4cdb0 rbx 0xffff800023e4ce60 rdx 0x6746 __ALIGN_SIZE+0x5746 rcx 0xffff800020c06000 rax 0xffff800020c06000 r8 0xffffffff81ecbab3 kprintf+0x173 r9 0x1 r10 0x25 r11 0x55414c9c9c437d7b r12 0x3000000008 r13 0xffff800023e4cdc0 r14 0x100 r15 0x1 rip 0xffffffff81b7cd58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800023e4cda0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=225146 stat=onproc flags process=0 proc=4000000 pri=24, usrpri=68, nice=20 forw=0xffffffffffffffff, list=0xffff800020b28018,0xffff800020b29b50 process=0xffff800020b7dc00 user=0xffff800023e48000, vmspace=0xfffffd807effe2e0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 39245 322022 80474 0 2 0 syz-executor.0 *39245 225146 80474 0 7 0x4000000 syz-executor.0 39245 517101 80474 0 2 0x4000000 syz-executor.0 34207 396658 82783 0 2 0 syz-executor.1 34207 131610 82783 0 3 0x4000080 ttyout syz-executor.1 34207 390779 82783 0 3 0x4000080 fsleep syz-executor.1 34207 447171 82783 0 3 0x4000080 fsleep syz-executor.1 34207 516971 82783 0 2 0x4000000 syz-executor.1 49776 485847 0 0 3 0x14200 bored sosplice 82783 129471 1463 0 7 0x482 syz-executor.1 80474 260310 1463 0 2 0x482 syz-executor.0 1463 45549 47341 0 3 0x82 thrsleep syz-fuzzer 1463 83575 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 392263 47341 0 3 0x4000082 kqread syz-fuzzer 1463 284351 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 197817 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 457729 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 248681 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 123053 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 88745 47341 0 3 0x4000082 thrsleep syz-fuzzer 1463 100444 47341 0 3 0x4000082 thrsleep syz-fuzzer 47341 176743 42871 0 3 0x10008a pause ksh 42871 403491 53183 0 3 0x92 select sshd 13660 100123 1 0 3 0x100083 ttyin getty 53183 151200 1 0 3 0x80 select sshd 67746 303036 42514 74 3 0x100092 bpf pflogd 42514 336821 1 0 3 0x80 netio pflogd 78307 221264 74174 73 2 0x100090 syslogd 74174 348511 1 0 3 0x100082 netio syslogd 30829 298252 1 77 3 0x100090 poll dhclient 1646 456536 1 0 3 0x80 poll dhclient 90716 186933 0 0 2 0x14200 zerothread 99349 255760 0 0 3 0x14200 aiodoned aiodoned 91632 342818 0 0 3 0x14200 syncer update 29674 205778 0 0 3 0x14200 cleaner cleaner 68269 25766 0 0 3 0x14200 reaper reaper 61753 338597 0 0 3 0x14200 pgdaemon pagedaemon 48627 178713 0 0 3 0x14200 bored crynlk 18168 420120 0 0 3 0x14200 bored crypto 19102 134215 0 0 3 0x40014200 acpi0 acpi0 53834 13233 0 0 3 0x40014200 idle1 99176 121608 0 0 3 0x14200 bored softnet 66286 289957 0 0 3 0x14200 bored systqmp 31926 163797 0 0 3 0x14200 bored systq 76442 469162 0 0 3 0x40014200 bored softclock 84710 488917 0 0 3 0x40014200 idle0 23736 10079 0 0 2 0x14200 smr 1 509348 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 39245 (syz-executor.0) thread 0xffff800020b28508 (225146) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8239e0c8) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 __mp_acquire_count+0x51 sys/kern/kern_lock.c:227 #2 mi_switch+0x38f sys/kern/sched_bsd.c:441 #3 sleep_finish+0x113 sys/kern/kern_synch.c:373 #4 tsleep+0x198 sleep_finish_timeout sys/kern/kern_synch.c:397 [inline] #4 tsleep+0x198 sleep_finish_all sys/kern/kern_synch.c:183 [inline] #4 tsleep+0x198 sys/kern/kern_synch.c:152 #5 fifo_open+0x3b6 sys/miscfs/fifofs/fifo_vnops.c:194 #6 VOP_OPEN+0x6a sys/kern/vfs_vops.c:153 #7 vn_open+0x495 sys/kern/vfs_vnops.c:174 #8 diskmapioctl+0x1ba sys/dev/diskmap.c:89 #9 VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290 #10 vn_ioctl+0xb6 sys/kern/vfs_vnops.c:519 #11 sys_ioctl+0x5b8 #12 syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] #12 syscall+0x552 sys/arch/amd64/amd64/trap.c:555 #13 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9495 6524K 6776K 78643K 11065 0 0 pcb 13 8K 8K 78643K 25 0 0 rtable 108 4K 4K 78643K 281 0 0 ifaddr 46 11K 12K 78643K 91 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1479 0 0 iov 0 0K 16K 78643K 19 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1220 77K 77K 78643K 1382 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 3 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 0K 78643K 16 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 6 17K 25K 78643K 223 0 0 sigio 0 0K 0K 78643K 4 0 0 proc 53 50K 83K 78643K 434 0 0 subproc 32 2K 2K 78643K 34 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 20 0 0 in_multi 33 2K 2K 78643K 35 0 0 ether_multi 1 0K 0K 78643K 1 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 42 185K 185K 78643K 42 0 0 exec 0 0K 1K 78643K 233 0 0 pagedep 1 8K 8K 78643K 1 0 0 inodedep 1 32K 32K 78643K 1 0 0 newblk 1 0K 0K 78643K 1 0 0 VM swap 7 26K 26K 78643K 7 0 0 UVM amap 105 21K 30K 78643K 1631 0 0 UVM aobj 8 2K 2K 78643K 10 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 NDP 8 0K 0K 78643K 24 0 0 temp 105 2733K 2800K 78643K 3940 0 0 kqueue 0 0K 0K 78643K 4 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{0}> 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 80 30 0 28 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 101 0 89 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 8190 0 8190 2 2 0 2 0 8 0 tcpcb 544 40 0 36 1 0 1 1 0 8 0 inpcb 280 95 0 88 1 0 1 1 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 0 1 1 0 8 1 ppxss 1128 7 0 7 1 0 1 1 0 8 1 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 15 0 3 1 0 1 1 0 8 0 pfstkey 112 15 0 3 1 0 1 1 0 8 0 pfstate 328 15 0 3 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 semapl 112 14 0 4 1 0 1 1 0 8 0 shmpl 112 8 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 1748 0 318 47 0 47 47 0 8 0 ffsino 272 1748 0 318 96 0 96 96 0 8 0 nchpl 144 2249 0 600 62 0 62 62 0 8 0 uvmvnodes 72 1898 0 0 35 0 35 35 0 8 0 vnodes 200 1898 0 0 100 0 100 100 0 8 0 namei 1024 6141 0 6141 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scxspl 192 5945 0 5945 8 7 1 6 0 8 1 plimitpl 152 25 0 15 1 0 1 1 0 8 0 sigapl 432 423 0 407 3 1 2 3 0 8 0 futexpl 56 2222 0 2220 1 0 1 1 0 8 0 knotepl 112 83 0 64 1 0 1 1 0 8 0 kqueuepl 104 38 0 36 1 0 1 1 0 8 0 pipepl 112 242 0 223 1 0 1 1 0 8 0 fdescpl 488 424 0 407 3 0 3 3 0 8 0 filepl 152 2240 0 2135 6 1 5 5 0 8 0 lockfpl 104 62 0 62 2 1 1 1 0 8 1 lockfspl 48 25 0 25 2 1 1 1 0 8 1 sessionpl 112 18 0 7 1 0 1 1 0 8 0 pgrppl 48 22 0 11 1 0 1 1 0 8 0 ucredpl 96 304 0 295 1 0 1 1 0 8 0 zombiepl 144 407 0 407 2 1 1 1 0 8 1 processpl 896 440 0 407 4 0 4 4 0 8 0 procpl 632 863 0 815 5 0 5 5 0 8 1 sosppl 128 5 0 5 2 1 1 1 0 8 1 sockpl 384 228 0 207 4 1 3 3 0 8 0 mcl64k 65536 4 0 0 1 0 1 1 0 8 0 mcl12k 12288 3 0 0 1 0 1 1 0 8 0 mcl9k 9216 3 0 0 1 0 1 1 0 8 0 mcl8k 8192 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 5 0 0 1 0 1 1 0 8 0 mcl2k 2048 195 0 0 24 0 24 24 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 207 0 0 13 0 13 13 0 8 0 bufpl 256 8178 0 1166 439 0 439 439 0 8 0 anonpl 16 52738 0 41879 62 7 55 61 0 125 10 amapchunkpl 152 2163 0 2049 11 5 6 10 0 158 1 amappl16 192 1801 0 1212 42 11 31 42 0 8 0 amappl15 184 3 0 2 1 0 1 1 0 8 0 amappl14 176 56 0 50 1 0 1 1 0 8 0 amappl13 168 6 0 6 1 1 0 1 0 8 0 amappl12 160 109 0 106 1 0 1 1 0 8 0 amappl11 152 155 0 138 1 0 1 1 0 8 0 amappl10 144 76 0 73 1 0 1 1 0 8 0 amappl9 136 600 0 597 1 0 1 1 0 8 0 amappl8 128 153 0 130 1 0 1 1 0 8 0 amappl7 120 36 0 32 1 0 1 1 0 8 0 amappl6 112 149 0 141 1 0 1 1 0 8 0 amappl5 104 228 0 213 1 0 1 1 0 8 0 amappl4 96 586 0 556 2 1 1 2 0 8 0 amappl3 88 280 0 267 1 0 1 1 0 8 0 amappl2 80 2466 0 2385 3 1 2 3 0 8 0 amappl1 72 19048 0 18579 26 16 10 20 0 8 0 amappl 80 1111 0 1069 1 0 1 1 0 84 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma64 64 259 0 259 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 17 0 17 1 1 0 1 0 8 0 aobjpl 64 9 0 2 1 0 1 1 0 8 0 uaddrrnd 24 424 0 407 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 424 0 407 1 0 1 1 0 8 0 vmmpekpl 168 7106 0 7071 2 0 2 2 0 8 0 vmmpepl 168 57805 0 55960 122 37 85 95 0 357 4 vmsppl 368 423 0 407 2 0 2 2 0 8 0 pdppl 4096 856 0 814 6 0 6 6 0 8 0 pvpl 32 171692 0 157093 168 23 145 151 0 265 27 pmappl 232 423 0 407 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 606 0 4 18 0 18 18 0 8 0