panic: mutex 0xfffffd806e5f6730 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *464508 8034 0 0 0x4000000 0 syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8243aab0) at panic+0x161 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806f10f070) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800021719410,fffffd806f10f070) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5f6730,ffff800021719410,ffff800021660fc0) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021660fc0,ffff800021719608,ffff800021719660) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000217196d0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x29187642570, count: 7 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> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic *cpu0: mutex 0xfffffd806e5f6730 not held in knote_dequeue ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8243aab0) at panic+0x161 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806f10f070) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800021719410,fffffd806f10f070) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5f6730,ffff800021719410,ffff800021660fc0) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021660fc0,ffff800021719608,ffff800021719660) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000217196d0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x29187642570, count: -8 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff800021719140 rbx 0 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81d4e795 kprintf+0x145 r9 0x1 r10 0x34da37c032a2f39 r11 0xe0eeeff7165bd719 r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff81dfed58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800021719130 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=464508 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000216617a0,0xffffffff82868538 process=0xffff80002164e3e8 user=0xffff800021714000, vmspace=0xfffffd8066484890 estcpu=36, cpticks=6, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 8034 169790 97653 0 2 0 syz-executor.1 * 8034 464508 97653 0 7 0x4000000 syz-executor.1 28773 327743 0 0 3 0x14200 bored sosplice 24145 513066 1014 0 3 0x2 biowait syz-executor.0 97653 11474 1014 0 3 0x82 nanoslp syz-executor.1 1014 317878 76021 0 3 0x82 thrsleep syz-fuzzer 1014 250673 76021 0 3 0x4000082 nanoslp syz-fuzzer 1014 269905 76021 0 3 0x4000082 thrsleep syz-fuzzer 1014 99493 76021 0 3 0x4000082 thrsleep syz-fuzzer 1014 281012 76021 0 3 0x4000082 thrsleep syz-fuzzer 1014 431354 76021 0 3 0x4000082 thrsleep syz-fuzzer 1014 347087 76021 0 3 0x4000082 kqread syz-fuzzer 76021 54050 35758 0 3 0x10008a sigsusp ksh 35758 47409 2124 0 3 0x92 select sshd 57577 392194 1 0 3 0x100083 ttyin getty 2124 78290 1 0 3 0x80 select sshd 20590 24249 42014 73 3 0x100090 kqread syslogd 42014 315720 1 0 3 0x100082 netio syslogd 37761 159792 1 77 3 0x100090 poll dhclient 75027 366544 1 0 3 0x80 poll dhclient 88039 519160 0 0 3 0x14200 bored smr 61957 250344 0 0 2 0x14200 zerothread 20631 229873 0 0 3 0x14200 aiodoned aiodoned 76047 283798 0 0 3 0x14200 syncer update 45515 454569 0 0 3 0x14200 cleaner cleaner 9342 50379 0 0 3 0x14200 reaper reaper 7548 489519 0 0 3 0x14200 pgdaemon pagedaemon 63800 117817 0 0 3 0x14200 bored crynlk 54606 293002 0 0 3 0x14200 bored crypto 49058 100517 0 0 3 0x14200 bored viomb 13887 372108 0 0 3 0x40014200 acpi0 acpi0 5709 349337 0 0 3 0x14200 bored softnet 91231 447066 0 0 3 0x14200 bored systqmp 60373 18106 0 0 3 0x14200 bored systq 3032 170085 0 0 3 0x40014200 bored softclock 47778 255551 0 0 3 0x40014200 idle0 1 231343 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10128 6424K 7766K 78643K 13449 0 pcb 13 8K 8K 78643K 137 0 rtable 107 3K 5K 78643K 535 0 ifaddr 54 12K 12K 78643K 118 0 counters 21 16K 16K 78643K 31 0 ioctlops 0 0K 4K 78643K 122 0 iov 0 0K 12K 78643K 76 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1225 77K 77K 78643K 2030 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 9 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 443 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 2374 0 sigio 0 0K 0K 78643K 21 0 proc 51 38K 62K 78643K 578 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 170 0 in_multi 33 2K 2K 78643K 112 0 ether_multi 1 0K 0K 78643K 39 0 mrt 0 0K 0K 78643K 60 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 43 201K 201K 78643K 43 0 exec 0 0K 2K 78643K 362 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 191 91K 91K 78643K 29187 0 UVM aobj 3 2K 2K 78643K 3 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 154 0 NDP 8 0K 0K 78643K 22 0 temp 113 3977K 4042K 78643K 9420 0 kqueue 5 5K 16K 78643K 198 0 SYN cache 2 16K 16K 78643K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 90 0 88 1 0 1 1 0 8 0 rtentry 112 93 0 48 2 0 2 2 0 8 0 unpcb 120 682 0 660 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 39 0 39 3 3 0 1 0 8 0 tcpcb 736 327 0 313 12 10 2 4 0 8 0 arp 88 7 0 1 1 0 1 1 0 8 0 inpcb 304 882 0 876 1 0 1 1 0 8 0 rttmr 72 30 0 30 2 2 0 1 0 8 0 nd6 48 7 0 0 1 0 1 1 0 8 0 pkpcb 40 26 0 26 3 3 0 1 0 8 0 kcovpl 48 2 0 0 1 0 1 1 0 8 0 ppxss 1128 7 0 7 1 1 0 1 0 8 0 pfrktable 1344 66 0 66 1 1 0 1 0 8 0 pfrule 1360 90 0 76 4 2 2 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 233 0 9 15 0 15 15 0 8 0 art_table 32 234 0 9 2 0 2 2 0 8 0 art_node 16 92 0 51 1 0 1 1 0 8 0 sysvmsgpl 40 41 0 1 1 0 1 1 0 8 0 semupl 112 9 0 9 1 1 0 1 0 8 0 semapl 112 441 0 431 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 4671 0 3270 89 0 89 89 0 8 0 ffsino 240 4671 0 3270 84 0 84 84 0 8 0 nchpl 144 7774 0 6166 60 0 60 60 0 8 0 uvmvnodes 72 5257 0 0 96 0 96 96 0 8 0 vnodes 224 5257 0 0 310 0 310 310 0 8 0 namei 1024 19289 0 19288 1 0 1 1 0 8 0 vcpupl 1984 5 0 0 1 0 1 1 0 8 0 vmpool 528 5 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 22 0 22 1 1 0 1 0 8 0 scxspl 216 22485 0 22484 9 8 1 8 0 8 0 plimitpl 152 56 0 49 1 0 1 1 0 8 0 sigapl 424 2561 0 2531 4 0 4 4 0 8 0 futexpl 56 23498 0 23498 1 0 1 1 0 8 1 knotepl 112 236 0 214 1 0 1 1 0 8 0 kqueuepl 184 1557 0 1554 1 0 1 1 0 8 0 pipepl 304 198 0 187 6 4 2 2 0 8 1 fdescpl 432 2545 0 2531 2 0 2 2 0 8 0 filepl 120 9677 0 9579 4 0 4 4 0 8 1 lockfpl 104 216 0 215 1 0 1 1 0 8 0 lockfspl 48 73 0 72 1 0 1 1 0 8 0 sessionpl 144 17 0 7 1 0 1 1 0 8 0 pgrppl 48 49 0 39 1 0 1 1 0 8 0 ucredpl 96 1356 0 1349 1 0 1 1 0 8 0 zombiepl 144 2531 0 2531 1 0 1 1 0 8 1 processpl 1016 2561 0 2531 5 1 4 5 0 8 0 procpl 672 5102 0 5065 4 0 4 4 0 8 0 sosppl 168 41 0 41 1 1 0 1 0 8 0 sockpl 448 1695 0 1665 10 5 5 5 0 8 1 mcl64k 65536 56 0 56 5 4 1 1 0 8 1 mcl16k 16384 19 0 19 2 2 0 1 0 8 0 mcl12k 12288 160 0 160 7 6 1 1 0 8 1 mcl9k 9216 30 0 30 4 4 0 1 0 8 0 mcl8k 8192 48 0 48 7 6 1 1 0 8 1 mcl4k 4096 86 0 86 6 5 1 1 0 8 1 mcl2k 2048 30213 0 30139 38 24 14 17 0 8 3 mtagpl 96 146 0 34 4 1 3 3 0 8 0 mbufpl 256 116078 0 115747 57 31 26 35 0 8 1 bufpl 280 6137 0 144 429 0 429 429 0 8 0 anonpl 24 632552 0 623253 67 10 57 57 0 188 0 amapchunkpl 152 68075 0 67691 22 5 17 17 0 158 0 amappl16 200 5074 0 4767 24 7 17 17 0 8 0 amappl15 192 53 0 47 1 0 1 1 0 8 0 amappl14 184 4 0 2 1 0 1 1 0 8 0 amappl13 176 51 0 50 1 0 1 1 0 8 0 amappl12 168 1163 0 1160 1 0 1 1 0 8 0 amappl11 160 36 0 28 1 0 1 1 0 8 0 amappl10 152 36 0 30 1 0 1 1 0 8 0 amappl9 144 220 0 218 1 0 1 1 0 8 0 amappl8 136 1540 0 1484 2 0 2 2 0 8 0 amappl7 128 1242 0 1238 1 0 1 1 0 8 0 amappl6 120 99 0 84 1 0 1 1 0 8 0 amappl5 112 2499 0 2491 1 0 1 1 0 8 0 amappl4 104 490 0 465 1 0 1 1 0 8 0 amappl3 96 1453 0 1443 1 0 1 1 0 8 0 amappl2 88 2730 0 2686 4 2 2 2 0 8 1 amappl1 80 41607 0 41222 12 3 9 12 0 8 0 amappl 88 28657 0 28540 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 2550 0 2531 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2550 0 2531 1 0 1 1 0 8 0 vmmpekpl 168 14119 0 14098 2 0 2 2 0 8 0 vmmpepl 168 285096 0 283612 72 3 69 69 0 357 2 vmsppl 272 2549 0 2531 3 1 2 2 0 8 0 rwobjpl 24 49248 0 48305 7 1 6 6 0 8 0 pdppl 4096 5106 0 5067 55 14 41 41 0 8 2 pvpl 32 1461501 0 1448625 166 60 106 128 0 265 2 pmappl 200 2549 0 2531 4 2 2 2 0 8 1 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 400 0 107 9 0 9 9 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8243aab0) at panic+0x161 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806f10f070) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800021719410,fffffd806f10f070) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5f6730,ffff800021719410,ffff800021660fc0) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021660fc0,ffff800021719608,ffff800021719660) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000217196d0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x29187642570, count: -8 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8243aab0) at panic+0x161 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806f10f070) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800021719410,fffffd806f10f070) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5f6730,ffff800021719410,ffff800021660fc0) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021660fc0,ffff800021719608,ffff800021719660) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000217196d0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x29187642570, count: -8