panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *429314 967 0 0 0x4000000 0K syz-executor.1 512053 17256 0 0 0 1 syz-executor.0 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(fffffd807e114cd0) at vrele+0x188 sys/kern/vfs_subr.c:797 diskmapioctl(5a00,c0106477,ffff800020c19300,1,ffff800020b50290) at diskmapioctl+0x2a8 sys/dev/diskmap.c:140 VOP_IOCTL(fffffd806fac68a0,c0106477,ffff800020c19300,1,fffffd807f7c6b40,ffff800020b50290) at VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290 vn_ioctl(fffffd80682160b0,c0106477,ffff800020c19300,ffff800020b50290) at vn_ioctl+0xb6 sys/kern/vfs_vnops.c:519 sys_ioctl(ffff800020b50290,ffff800020c19418,ffff800020c19480) at sys_ioctl+0x5b8 syscall(ffff800020c194f0) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800020c194f0) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffff1f,0,3,f71788d2010) at Xsyscall+0x128 end of kernel end trace frame: 0xf73ceb37d10, 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(fffffd807e114cd0) at vrele+0x188 sys/kern/vfs_subr.c:797 diskmapioctl(5a00,c0106477,ffff800020c19300,1,ffff800020b50290) at diskmapioctl+0x2a8 sys/dev/diskmap.c:140 VOP_IOCTL(fffffd806fac68a0,c0106477,ffff800020c19300,1,fffffd807f7c6b40,ffff800020b50290) at VOP_IOCTL+0x88 sys/kern/vfs_vops.c:290 vn_ioctl(fffffd80682160b0,c0106477,ffff800020c19300,ffff800020b50290) at vn_ioctl+0xb6 sys/kern/vfs_vnops.c:519 sys_ioctl(ffff800020b50290,ffff800020c19418,ffff800020c19480) at sys_ioctl+0x5b8 syscall(ffff800020c194f0) at syscall+0x552 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800020c194f0) at syscall+0x552 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffff1f,0,3,f71788d2010) at Xsyscall+0x128 end of kernel end trace frame: 0xf73ceb37d10, count: -9 ddb{0}> show registers rdi 0xffffffff81dcdf97 db_enter+0x17 rsi 0x66b9 __ALIGN_SIZE+0x56b9 rbp 0xffff800020c18ec0 rbx 0xffff800020c18f70 rdx 0x66ba __ALIGN_SIZE+0x56ba rcx 0xffff80002141c000 rax 0xffff80002141c000 r8 0xffffffff81386d93 kprintf+0x173 r9 0x1 r10 0x25 r11 0xb3ffb2db4ed90bf5 r12 0x3000000008 r13 0xffff800020c18ed0 r14 0x100 r15 0x1 rip 0xffffffff81dcdf98 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c18eb0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=429314 stat=onproc flags process=0 proc=4000000 pri=24, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b50780,0xffff800020b51b50 process=0xffff800020aebc08 user=0xffff800020c14000, vmspace=0xfffffd807f00b450 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 967 214250 35404 0 2 0 syz-executor.1 * 967 429314 35404 0 7 0x4000000 syz-executor.1 967 228393 35404 0 2 0x4000000 syz-executor.1 17256 512053 54673 0 7 0 syz-executor.0 17256 192131 54673 0 3 0x4000080 poll syz-executor.0 17256 386215 54673 0 3 0x4000080 poll syz-executor.0 50580 173816 1 0 3 0x100083 ttyin getty 35404 68327 52369 0 2 0x482 syz-executor.1 38568 244336 0 0 3 0x14200 bored sosplice 54673 315778 52369 0 2 0x482 syz-executor.0 52369 380015 84603 0 3 0x82 thrsleep syz-fuzzer 52369 273770 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 460350 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 20315 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 305649 84603 0 3 0x4000082 kqread syz-fuzzer 52369 325617 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 343676 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 109405 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 335620 84603 0 3 0x4000082 thrsleep syz-fuzzer 52369 389538 84603 0 3 0x4000082 thrsleep syz-fuzzer 84603 127984 10078 0 3 0x10008a pause ksh 10078 231329 53267 0 3 0x92 select sshd 53267 163016 1 0 3 0x80 select sshd 8227 325218 22237 74 3 0x100092 bpf pflogd 22237 47418 1 0 3 0x80 netio pflogd 6635 207493 62390 73 2 0x100090 syslogd 62390 89275 1 0 3 0x100082 netio syslogd 96676 324604 1 77 3 0x100090 poll dhclient 44282 82592 1 0 3 0x80 poll dhclient 7031 378251 0 0 2 0x14200 zerothread 36929 471381 0 0 3 0x14200 aiodoned aiodoned 2319 293027 0 0 3 0x14200 syncer update 59857 325044 0 0 3 0x14200 cleaner cleaner 88054 32814 0 0 3 0x14200 reaper reaper 68547 273547 0 0 3 0x14200 pgdaemon pagedaemon 90272 255975 0 0 3 0x14200 bored crynlk 66463 257798 0 0 3 0x14200 bored crypto 94966 492658 0 0 3 0x40014200 acpi0 acpi0 99221 174073 0 0 3 0x40014200 idle1 21816 4608 0 0 3 0x14200 bored softnet 75433 181531 0 0 3 0x14200 bored systqmp 23151 174905 0 0 3 0x14200 bored systq 43543 385545 0 0 3 0x40014200 bored softclock 64842 501560 0 0 3 0x40014200 idle0 97472 200704 0 0 3 0x14200 bored smr 1 509244 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 967 (syz-executor.1) thread 0xffff800020b50290 (429314) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8238f2b8) #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 9563 6433K 7460K 78643K 16866 0 0 pcb 13 8K 8K 78643K 140 0 0 rtable 111 4K 4K 78643K 1011 0 0 ifaddr 73 18K 19K 78643K 450 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1563 0 0 iov 0 0K 20K 78643K 155 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1220 77K 77K 78643K 3861 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 28 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 0K 1K 78643K 964 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 6 17K 25K 78643K 2879 0 0 sigio 0 0K 0K 78643K 10 0 0 proc 54 51K 83K 78643K 640 0 0 subproc 32 2K 2K 78643K 51 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 174 0 0 in_multi 33 2K 2K 78643K 107 0 0 ether_multi 1 0K 0K 78643K 11 0 0 mrt 0 0K 0K 78643K 14 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 78 344K 344K 78643K 78 0 0 exec 0 0K 1K 78643K 357 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 99 21K 30K 78643K 9220 0 0 UVM aobj 76 5K 5K 78643K 89 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 0K 78643K 118 0 0 NDP 17 0K 0K 78643K 138 0 0 temp 207 2748K 2820K 78643K 11910 0 0 kqueue 0 0K 0K 78643K 22 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 8 0 2 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 77 0 75 1 0 1 1 0 8 0 rtentry 112 59 0 15 2 0 2 2 0 8 0 unpcb 120 492 0 480 1 0 1 1 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpqe 32 9984 0 9984 3 3 0 2 0 8 0 tcpcb 544 275 0 271 1 0 1 1 0 8 0 inpcb 280 741 0 734 1 0 1 1 0 8 0 rttmr 72 3 0 3 3 3 0 1 0 8 0 nd6 48 9 0 3 1 0 1 1 0 8 0 pkpcb 40 4 0 4 1 1 0 1 0 8 0 swfcl 56 2 0 0 1 0 1 1 0 8 0 ppxss 1128 25 0 25 6 6 0 1 0 8 0 pffrag 232 3 0 3 2 2 0 1 0 482 0 pffrnode 88 3 0 3 2 2 0 1 0 8 0 pffrent 40 8 0 8 2 2 0 1 0 8 0 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 40 0 36 1 0 1 1 0 8 0 pfstkey 112 40 0 36 1 0 1 1 0 8 0 pfstate 328 40 0 36 2 1 1 2 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 256 235 0 44 13 1 12 12 0 8 0 art_table 32 236 0 44 2 0 2 2 0 8 0 art_node 16 58 0 18 1 0 1 1 0 8 0 sysvmsgpl 40 24 0 16 1 0 1 1 0 8 0 semapl 112 950 0 940 1 0 1 1 0 8 0 shmpl 112 87 0 13 3 0 3 3 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 7392 0 5974 47 0 47 47 0 8 0 ffsino 272 7392 0 5974 96 0 96 96 0 8 0 nchpl 144 11258 0 9618 62 0 62 62 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 200 5926 0 0 312 0 312 312 0 8 0 namei 1024 34683 0 34683 2 1 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 54 0 54 2 1 1 1 0 8 1 scxspl 192 31191 0 31191 15 14 1 6 0 8 1 plimitpl 152 153 0 145 1 0 1 1 0 8 0 sigapl 432 3077 0 3061 3 1 2 3 0 8 0 futexpl 56 37143 0 37143 1 0 1 1 0 8 1 knotepl 112 440 0 421 1 0 1 1 0 8 0 kqueuepl 104 551 0 549 1 0 1 1 0 8 0 pipepl 112 1130 0 1111 3 2 1 2 0 8 0 fdescpl 488 3078 0 3061 3 0 3 3 0 8 0 filepl 152 15166 0 15064 7 2 5 5 0 8 1 lockfpl 104 2107 0 2107 4 4 0 1 0 8 0 lockfspl 48 969 0 969 4 4 0 1 0 8 0 sessionpl 112 20 0 9 1 0 1 1 0 8 0 pgrppl 48 38 0 27 1 0 1 1 0 8 0 ucredpl 96 1992 0 1983 1 0 1 1 0 8 0 zombiepl 144 3061 0 3061 2 1 1 1 0 8 1 processpl 896 3094 0 3061 4 0 4 4 0 8 0 procpl 632 8389 0 8343 11 6 5 5 0 8 1 srpgc 64 5 0 5 3 3 0 1 0 8 0 sosppl 128 22 0 22 4 4 0 1 0 8 0 sockpl 384 1332 0 1311 7 4 3 3 0 8 0 mcl64k 65536 9 0 0 2 0 2 2 0 8 0 mcl16k 16384 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 19 0 0 2 0 2 2 0 8 0 mcl9k 9216 10 0 0 1 0 1 1 0 8 0 mcl8k 8192 33 0 0 5 2 3 3 0 8 0 mcl4k 4096 8 0 0 1 0 1 1 0 8 0 mcl2k2 2112 4 0 0 1 0 1 1 0 8 0 mcl2k 2048 265 0 0 32 6 26 32 0 8 0 mtagpl 80 20 0 0 1 0 1 1 0 8 0 mbufpl 256 336 0 0 17 1 16 17 0 8 0 bufpl 256 12198 0 5169 440 0 440 440 0 8 0 anonpl 16 279575 0 267826 74 24 50 64 0 125 0 amapchunkpl 152 14931 0 14818 15 9 6 10 0 158 0 amappl16 192 16477 0 15824 57 24 33 45 0 8 0 amappl15 184 8 0 8 1 1 0 1 0 8 0 amappl14 176 713 0 704 1 0 1 1 0 8 0 amappl13 168 6 0 6 1 1 0 1 0 8 0 amappl12 160 5 0 4 1 0 1 1 0 8 0 amappl11 152 63 0 48 1 0 1 1 0 8 0 amappl10 144 930 0 923 1 0 1 1 0 8 0 amappl9 136 1943 0 1938 1 0 1 1 0 8 0 amappl8 128 1521 0 1492 2 0 2 2 0 8 0 amappl7 120 890 0 886 1 0 1 1 0 8 0 amappl6 112 59 0 50 1 0 1 1 0 8 0 amappl5 104 155 0 141 1 0 1 1 0 8 0 amappl4 96 3345 0 3312 2 1 1 2 0 8 0 amappl3 88 877 0 866 1 0 1 1 0 8 0 amappl2 80 24226 0 24146 3 1 2 3 0 8 0 amappl1 72 71259 0 70798 26 16 10 20 0 8 0 amappl 80 8665 0 8624 2 0 2 2 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 88 0 13 2 0 2 2 0 8 0 uaddrrnd 24 3078 0 3061 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3078 0 3061 1 0 1 1 0 8 0 vmmpekpl 168 21960 0 21929 2 0 2 2 0 8 0 vmmpepl 168 369671 0 367766 156 72 84 101 0 357 1 vmsppl 368 3077 0 3061 2 0 2 2 0 8 0 pdppl 4096 6163 0 6122 7 1 6 6 0 8 0 pvpl 32 787515 0 772475 225 99 126 160 0 265 0 pmappl 232 3077 0 3061 2 1 1 2 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 627 0 15 18 0 18 18 0 8 0