panic: vrele: v_writecount != 0 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *305264 18355 32767 0x10 0x4000000 0K syz-executor.0 294448 48307 32767 0x10 0x480 1 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(fffffd806e53a4e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256d6580,3,ffff8000ffff4fc0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e622050,40287401,ffff8000256d6580,3,fffffd807f7b7ae0,ffff8000ffff4fc0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80663f6ad0,40287401,ffff8000256d6580,ffff8000ffff4fc0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4fc0,ffff8000256d6690,ffff8000256d66e0) at sys_ioctl+0x4b0 syscall(ffff8000256d6760) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256d6760) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x879449123d0, 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(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e53a4e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256d6580,3,ffff8000ffff4fc0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e622050,40287401,ffff8000256d6580,3,fffffd807f7b7ae0,ffff8000ffff4fc0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80663f6ad0,40287401,ffff8000256d6580,ffff8000ffff4fc0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4fc0,ffff8000256d6690,ffff8000256d66e0) at sys_ioctl+0x4b0 syscall(ffff8000256d6760) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256d6760) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x879449123d0, count: -9 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000256d5fc0 rbx 0xffff8000256d5fd0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff81ea78f5 kprintf+0x145 r9 0x1 r10 0xc220d0317c036935 r11 0xbcee54a996007884 r12 0x3000000008 r13 0xffff8000256d6070 r14 0x100 r15 0x1 rip 0xffffffff8184d248 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000256d5fb0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=305264 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff4540,0xffff8000ffff4010 process=0xffff8000ffff2e88 user=0xffff8000256d1000, vmspace=0xfffffd807effa5c0 estcpu=36, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 18355 164670 48307 32767 2 0x10 syz-executor.0 *18355 305264 48307 32767 7 0x4000010 syz-executor.0 18355 299292 48307 32767 3 0x4000090 fsleep syz-executor.0 24191 349929 38574 32767 2 0x10 syz-executor.1 24191 200092 38574 32767 3 0x4000090 semwait syz-executor.1 24191 349968 38574 32767 3 0x4000090 fsleep syz-executor.1 38574 250794 64563 32767 2 0x490 syz-executor.1 48307 294448 53129 32767 7 0x490 syz-executor.0 64563 431902 74333 0 3 0x82 wait syz-executor.1 53129 453518 74333 0 3 0x82 wait syz-executor.0 74333 218694 47945 0 3 0x82 thrsleep syz-fuzzer 74333 76512 47945 0 3 0x4000082 thrsleep syz-fuzzer 74333 485100 47945 0 3 0x4000082 kqread syz-fuzzer 74333 72573 47945 0 3 0x4000082 thrsleep syz-fuzzer 74333 361615 47945 0 3 0x4000082 thrsleep syz-fuzzer 74333 309087 47945 0 3 0x4000082 thrsleep syz-fuzzer 74333 62199 47945 0 3 0x4000082 thrsleep syz-fuzzer 74333 445306 47945 0 3 0x4000082 thrsleep syz-fuzzer 47945 72943 40112 0 3 0x10008a sigsusp ksh 40112 160533 53144 0 3 0x92 select sshd 9411 107647 1 0 3 0x100083 ttyin getty 53144 289742 1 0 3 0x80 select sshd 7760 104337 8108 73 3 0x100090 kqread syslogd 8108 489965 1 0 3 0x100082 netio syslogd 25687 205504 1 77 3 0x100090 poll dhclient 23843 190044 1 0 3 0x80 poll dhclient 87496 336753 0 0 3 0x14200 bored smr 42792 147149 0 0 2 0x14200 zerothread 38601 4790 0 0 3 0x14200 aiodoned aiodoned 85380 298472 0 0 3 0x14200 syncer update 17420 168331 0 0 3 0x14200 cleaner cleaner 20852 239950 0 0 3 0x14200 reaper reaper 75853 14004 0 0 3 0x14200 pgdaemon pagedaemon 99157 44877 0 0 3 0x14200 bored crynlk 8016 415880 0 0 3 0x14200 bored crypto 96860 314954 0 0 3 0x14200 bored viomb 98761 126582 0 0 3 0x40014200 acpi0 acpi0 66822 513600 0 0 3 0x40014200 idle1 10470 500196 0 0 3 0x14200 bored softnet 83659 182720 0 0 3 0x14200 bored systqmp 71850 383187 0 0 3 0x14200 bored systq 2286 303653 0 0 3 0x40014200 bored softclock 92165 58132 0 0 3 0x40014200 idle0 1 361501 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 18355 (syz-executor.0) thread 0xffff8000ffff4fc0 (305264) 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{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9476 6349K 6349K 78643K 10566 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 15 0 mount 1 1K 1K 78643K 1 0 vnodes 1216 76K 76K 78643K 1221 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 4 0K 0K 78643K 4 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 8 25K 33K 78643K 38 0 proc 48 50K 70K 78643K 365 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 25 122K 122K 78643K 25 0 exec 0 0K 2K 78643K 317 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 156 28K 28K 78643K 756 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 9 0K 0K 78643K 9 0 temp 61 3971K 4033K 78643K 1798 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 23 0 15 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 372 0 372 1 0 1 1 0 8 1 tcpcb 736 10 0 6 1 0 1 1 0 8 0 inpcb 304 32 0 25 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 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 189 0 0 12 0 12 12 0 8 0 art_table 32 190 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 semapl 112 1 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1418 0 21 88 0 88 88 0 8 0 ffsino 272 1418 0 21 94 0 94 94 0 8 0 nchpl 144 1637 0 36 60 0 60 60 0 8 0 uvmvnodes 72 1461 0 0 27 0 27 27 0 8 0 vnodes 224 1461 0 0 86 0 86 86 0 8 0 namei 1024 3980 0 3980 2 1 1 1 0 8 1 percpumem 16 33 0 0 1 0 1 1 0 8 0 scxspl 216 4781 0 4781 9 3 6 8 0 8 6 plimitpl 152 17 0 7 1 0 1 1 0 8 0 sigapl 424 226 0 193 4 0 4 4 0 8 0 futexpl 56 12 0 10 1 0 1 1 0 8 0 knotepl 112 62 0 42 1 0 1 1 0 8 0 kqueuepl 168 3 0 0 1 0 1 1 0 8 0 pipepl 336 69 0 58 1 0 1 1 0 8 0 fdescpl 496 210 0 193 3 0 3 3 0 8 0 filepl 152 968 0 865 5 1 4 4 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 7 1 0 1 1 0 8 0 pgrppl 48 17 0 7 1 0 1 1 0 8 0 ucredpl 96 57 0 48 1 0 1 1 0 8 0 zombiepl 144 193 0 193 2 1 1 1 0 8 1 processpl 1080 226 0 193 5 2 3 3 0 8 0 procpl 672 237 0 193 4 0 4 4 0 8 0 sockpl 432 74 0 57 4 1 3 3 0 8 1 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 190 0 0 22 0 22 22 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 223 0 0 13 0 13 13 0 8 0 bufpl 280 3255 0 173 221 0 221 221 0 8 0 anonpl 24 45247 0 20774 152 3 149 149 0 186 1 amapchunkpl 152 1528 0 924 26 0 26 26 0 158 0 amappl16 200 1054 0 111 50 0 50 50 0 8 0 amappl15 192 2 0 0 1 0 1 1 0 8 0 amappl14 184 23 0 19 1 0 1 1 0 8 0 amappl13 176 28 0 22 2 1 1 1 0 8 0 amappl12 168 9 0 7 2 1 1 1 0 8 0 amappl11 160 49 0 37 1 0 1 1 0 8 0 amappl10 152 18 0 13 1 0 1 1 0 8 0 amappl9 144 266 0 262 2 1 1 1 0 8 0 amappl8 136 146 0 99 2 0 2 2 0 8 0 amappl7 128 221 0 210 1 0 1 1 0 8 0 amappl6 120 61 0 51 1 0 1 1 0 8 0 amappl5 112 392 0 375 1 0 1 1 0 8 0 amappl4 104 245 0 222 1 0 1 1 0 8 0 amappl3 96 116 0 108 1 0 1 1 0 8 0 amappl2 88 846 0 771 4 2 2 3 0 8 0 amappl1 80 14025 0 13491 27 15 12 21 0 8 1 amappl 88 522 0 417 3 0 3 3 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 24 210 0 193 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 210 0 193 1 0 1 1 0 8 0 vmmpekpl 168 5778 0 5749 2 0 2 2 0 8 0 vmmpepl 168 34518 0 32084 146 14 132 132 0 357 26 vmsppl 368 209 0 193 2 0 2 2 0 8 0 rwobjpl 56 9685 0 7978 32 6 26 26 0 8 1 pdppl 4096 427 0 386 63 18 45 45 0 8 4 pvpl 32 134747 0 107159 226 0 226 226 0 265 3 pmappl 232 209 0 193 2 0 2 2 0 8 1 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 306 0 21 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(ffffffff82460f22) at panic+0x15e sys/kern/subr_prf.c:218 vrele(fffffd806e53a4e8) at vrele+0x197 sys/kern/vfs_subr.c:803 ptmioctl(5100,40287401,ffff8000256d6580,3,ffff8000ffff4fc0) at ptmioctl+0x5b9 sys/kern/tty_pty.c:1225 VOP_IOCTL(fffffd806e622050,40287401,ffff8000256d6580,3,fffffd807f7b7ae0,ffff8000ffff4fc0) at VOP_IOCTL+0x9a sys/kern/vfs_vops.c:297 vn_ioctl(fffffd80663f6ad0,40287401,ffff8000256d6580,ffff8000ffff4fc0) at vn_ioctl+0xba sys/kern/vfs_vnops.c:531 sys_ioctl(ffff8000ffff4fc0,ffff8000256d6690,ffff8000256d66e0) at sys_ioctl+0x4b0 syscall(ffff8000256d6760) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256d6760) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x879449123d0, 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 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x17 kd_curproc sys/dev/kcov.c:559 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x17 sys/dev/kcov.c:143 __mp_lock(ffffffff828cdb90) at __mp_lock+0x133 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) at __mp_lock+0x133 sys/kern/kern_lock.c:147 __mp_acquire_count(ffffffff828cdb90,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227 mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:433 sleep_finish(ffff8000234be5c8,1) at sleep_finish+0x111 sys/kern/kern_synch.c:427 sleep_finish_all(ffff8000234be5c8,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:457 [inline] sleep_finish_all(ffff8000234be5c8,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:402 tsleep(ffffffff8285873c,120,ffffffff823a4637,2) at tsleep+0x1f2 sys/kern/kern_synch.c:163 sys_nanosleep(ffff8000ffff57a0,ffff8000234be6f0,ffff8000234be740) at sys_nanosleep+0x1f5 sys/kern/kern_time.c:297 syscall(ffff8000234be7c0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234be7c0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5390, count: 2 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 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x17 kd_curproc sys/dev/kcov.c:559 [inline] __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x17 sys/dev/kcov.c:143 __mp_lock(ffffffff828cdb90) at __mp_lock+0x133 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cdb90) at __mp_lock+0x133 sys/kern/kern_lock.c:147 __mp_acquire_count(ffffffff828cdb90,1) at __mp_acquire_count+0x4c sys/kern/kern_lock.c:227 mi_switch() at mi_switch+0x390 sys/kern/sched_bsd.c:433 sleep_finish(ffff8000234be5c8,1) at sleep_finish+0x111 sys/kern/kern_synch.c:427 sleep_finish_all(ffff8000234be5c8,1) at sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:457 [inline] sleep_finish_all(ffff8000234be5c8,1) at sleep_finish_all+0x32 sys/kern/kern_synch.c:402 tsleep(ffffffff8285873c,120,ffffffff823a4637,2) at tsleep+0x1f2 sys/kern/kern_synch.c:163 sys_nanosleep(ffff8000ffff57a0,ffff8000234be6f0,ffff8000234be740) at sys_nanosleep+0x1f5 sys/kern/kern_time.c:297 syscall(ffff8000234be7c0) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234be7c0) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc5390, count: -13