panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 120996 18462 0 0 0 1 syz-executor.0 *183212 18462 0 0 0x4000000 0K syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e3266b0) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000220c18c0,3,ffff80002123cfc8) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e592758,40287401,ffff8000220c18c0,3,fffffd807f7b7600,ffff80002123cfc8) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80680b2c78,40287401,ffff8000220c18c0,ffff80002123cfc8) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123cfc8,ffff8000220c19d0,ffff8000220c1a20) at sys_ioctl+0x4b0 syscall(ffff8000220c1aa0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000220c1aa0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xca50c347810, 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(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e3266b0) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000220c18c0,3,ffff80002123cfc8) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e592758,40287401,ffff8000220c18c0,3,fffffd807f7b7600,ffff80002123cfc8) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80680b2c78,40287401,ffff8000220c18c0,ffff80002123cfc8) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123cfc8,ffff8000220c19d0,ffff8000220c1a20) at sys_ioctl+0x4b0 syscall(ffff8000220c1aa0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000220c1aa0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xca50c347810, count: -9 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000220c1300 rbx 0xffff8000220c1310 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81b81665 kprintf+0x145 r9 0x1 r10 0xd77ce1032ff84dc r11 0x5adbb76e89aebf0 r12 0x3000000008 r13 0xffff8000220c13b0 r14 0x100 r15 0x1 rip 0xffffffff81e4d228 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000220c12f0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=183212 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff80002123cd28,0xffffffff828c76b0 process=0xffff800021235528 user=0xffff8000220bc000, vmspace=0xfffffd807eff9170 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 18462 120996 30474 0 7 0 syz-executor.0 *18462 183212 30474 0 7 0x4000000 syz-executor.0 68644 509489 85028 0 2 0x482 syz-executor.1 30474 262930 85028 0 2 0x482 syz-executor.0 85028 228602 11081 0 3 0x82 thrsleep syz-fuzzer 85028 290565 11081 0 3 0x4000082 thrsleep syz-fuzzer 85028 139042 11081 0 3 0x4000082 thrsleep syz-fuzzer 85028 346002 11081 0 3 0x4000082 kqread syz-fuzzer 85028 189549 11081 0 3 0x4000082 thrsleep syz-fuzzer 85028 64457 11081 0 3 0x4000082 thrsleep syz-fuzzer 85028 351144 11081 0 3 0x4000082 thrsleep syz-fuzzer 85028 206053 11081 0 3 0x4000082 thrsleep syz-fuzzer 11081 473433 51993 0 3 0x10008a sigsusp ksh 51993 234010 19844 0 3 0x92 select sshd 54566 459350 1 0 3 0x100083 ttyin getty 19844 308811 1 0 3 0x80 select sshd 56424 61977 64758 74 3 0x100092 bpf pflogd 64758 406508 1 0 3 0x80 netio pflogd 32715 236086 68178 73 3 0x100090 kqread syslogd 68178 52350 1 0 3 0x100082 netio syslogd 30532 522121 1 77 3 0x100090 poll dhclient 78844 257250 1 0 3 0x80 poll dhclient 41608 28803 0 0 3 0x14200 bored smr 88471 312803 0 0 3 0x14200 pgzero zerothread 91737 339495 0 0 3 0x14200 aiodoned aiodoned 44418 104618 0 0 3 0x14200 syncer update 50087 410115 0 0 3 0x14200 cleaner cleaner 95919 341768 0 0 3 0x14200 reaper reaper 58058 251137 0 0 3 0x14200 pgdaemon pagedaemon 42150 304140 0 0 3 0x14200 bored crynlk 99756 177787 0 0 3 0x14200 bored crypto 87882 305276 0 0 3 0x14200 bored viomb 12250 300216 0 0 3 0x40014200 acpi0 acpi0 94980 249025 0 0 3 0x40014200 idle1 16879 483497 0 0 3 0x14200 bored softnet 17941 229783 0 0 3 0x14200 bored systqmp 82166 82002 0 0 3 0x14200 bored systq 78430 16045 0 0 3 0x40014200 bored softclock 10612 222832 0 0 3 0x40014200 idle0 1 448017 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 18462 (syz-executor.0) thread 0xffff80002123cfc8 (183212) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828d4128) #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{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9499 6484K 6484K 78643K 10597 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 201 0 ifaddr 49 11K 11K 78643K 50 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 4K 78643K 1469 0 iov 0 0K 2K 78643K 2 0 mount 1 1K 1K 78643K 1 0 vnodes 1219 77K 77K 78643K 1227 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 5 13K 25K 78643K 46 0 proc 59 63K 83K 78643K 447 0 subproc 32 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 4 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 358 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 121 24K 25K 78643K 826 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 11 0K 0K 78643K 11 0 temp 71 3972K 4036K 78643K 2074 0 kqueue 3 4K 4K 78643K 3 0 SYN cache 2 16K 16K 78643K 2 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 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 25 0 15 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 1086 0 1086 2 0 2 2 0 8 2 tcpcb 736 10 0 6 1 0 1 1 0 8 0 inpcb 304 41 0 34 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 pfosfp 40 1428 0 1005 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 13 0 0 1 0 1 1 0 8 0 pfstkey 112 13 0 0 1 0 1 1 0 8 0 pfstate 320 13 0 0 2 0 2 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 256 188 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 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1439 0 35 88 0 88 88 0 8 0 ffsino 272 1439 0 35 95 1 94 94 0 8 0 nchpl 144 1669 0 64 60 0 60 60 0 8 0 uvmvnodes 72 1487 0 0 28 0 28 28 0 8 0 vnodes 224 1487 0 0 88 0 88 88 0 8 0 namei 1024 4338 0 4338 2 1 1 1 0 8 1 percpumem 16 33 0 0 1 0 1 1 0 8 0 scxspl 216 4947 0 4947 9 1 8 8 0 8 8 plimitpl 152 19 0 10 1 0 1 1 0 8 0 sigapl 424 262 0 230 4 0 4 4 0 8 0 futexpl 56 85 0 85 1 0 1 1 0 8 1 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 4 0 2 1 0 1 1 0 8 0 pipepl 336 76 0 65 1 0 1 1 0 8 0 fdescpl 496 246 0 230 3 0 3 3 0 8 0 filepl 152 1134 0 1028 6 1 5 5 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 18 0 7 1 0 1 1 0 8 0 pgrppl 48 18 0 7 1 0 1 1 0 8 0 ucredpl 96 72 0 63 1 0 1 1 0 8 0 zombiepl 144 230 0 229 2 1 1 1 0 8 0 processpl 1080 262 0 229 3 0 3 3 0 8 0 procpl 672 289 0 248 5 1 4 4 0 8 0 sockpl 432 85 0 66 3 0 3 3 0 8 0 mcl64k 65536 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl4k 4096 4 0 0 1 0 1 1 0 8 0 mcl2k 2048 316 0 0 39 0 39 39 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 349 0 0 22 0 22 22 0 8 0 bufpl 280 3347 0 181 227 0 227 227 0 8 0 anonpl 24 38181 0 23111 94 1 93 93 0 186 1 amapchunkpl 152 1444 0 1112 17 1 16 16 0 158 1 amappl16 200 769 0 142 34 0 34 34 0 8 0 amappl15 192 1 0 0 1 0 1 1 0 8 0 amappl14 184 27 0 22 1 0 1 1 0 8 0 amappl13 176 28 0 25 1 0 1 1 0 8 0 amappl12 168 10 0 9 2 1 1 1 0 8 0 amappl11 160 55 0 38 1 0 1 1 0 8 0 amappl10 152 25 0 17 1 0 1 1 0 8 0 amappl9 144 297 0 295 1 0 1 1 0 8 0 amappl8 136 134 0 102 2 0 2 2 0 8 0 amappl7 128 256 0 248 1 0 1 1 0 8 0 amappl6 120 74 0 64 1 0 1 1 0 8 0 amappl5 112 385 0 367 1 0 1 1 0 8 0 amappl4 104 281 0 254 2 1 1 2 0 8 0 amappl3 96 121 0 114 1 0 1 1 0 8 0 amappl2 88 1092 0 1022 3 1 2 3 0 8 0 amappl1 80 15540 0 15059 27 14 13 21 0 8 1 amappl 88 576 0 498 2 0 2 2 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 24 246 0 230 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 246 0 230 1 0 1 1 0 8 0 vmmpekpl 168 6108 0 6078 3 1 2 2 0 8 0 vmmpepl 168 38339 0 36494 118 14 104 104 0 357 23 vmsppl 368 245 0 230 2 0 2 2 0 8 0 rwobjpl 56 10249 0 8911 28 7 21 21 0 8 2 pdppl 4096 499 0 460 65 20 45 45 0 8 6 pvpl 32 136206 0 118088 156 4 152 152 0 265 3 pmappl 232 245 0 230 2 0 2 2 0 8 1 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 338 0 25 9 0 9 9 0 8 0 ddb{0}> machine ddbcpu 0 Invalid cpu 0 ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff8245fb0e) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e3266b0) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000220c18c0,3,ffff80002123cfc8) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e592758,40287401,ffff8000220c18c0,3,fffffd807f7b7600,ffff80002123cfc8) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80680b2c78,40287401,ffff8000220c18c0,ffff80002123cfc8) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff80002123cfc8,ffff8000220c19d0,ffff8000220c1a20) at sys_ioctl+0x4b0 syscall(ffff8000220c1aa0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000220c1aa0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xca50c347810, count: -9 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffff800020d68ff0) 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(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 syscall(ffff8000238cff10) at syscall+0x3fd mi_syscall sys/sys/syscall_mi.h:93 [inline] syscall(ffff8000238cff10) at syscall+0x3fd sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6f40, count: 9 ddb{1}> trace x86_ipi_db(ffff800020d68ff0) 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(ffffffff828d3f20) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828d3f20) at __mp_lock+0x129 sys/kern/kern_lock.c:147 syscall(ffff8000238cff10) at syscall+0x3fd mi_syscall sys/sys/syscall_mi.h:93 [inline] syscall(ffff8000238cff10) at syscall+0x3fd sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7fffff6f40, count: -6