panic: mutex 0xfffffd806e5fec38 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *426146 51663 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(fffffd806ea68620) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff80002272f4a0,fffffd806ea68620) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5fec38,ffff80002272f4a0,ffff800021661a40) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021661a40,ffff80002272f6b8,ffff80002272f710) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002272f780) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x18472358640, 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 0xfffffd806e5fec38 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(fffffd806ea68620) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff80002272f4a0,fffffd806ea68620) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5fec38,ffff80002272f4a0,ffff800021661a40) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021661a40,ffff80002272f6b8,ffff80002272f710) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002272f780) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x18472358640, count: -8 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002272f1f0 rbx 0 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81d4e795 kprintf+0x145 r9 0x1 r10 0xc79e99e0d381ea25 r11 0xc562d4a2d4683f05 r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff81dfed58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002272f1e0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=426146 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffffc7e8,0xffffffff82868538 process=0xffff80002164dff0 user=0xffff80002272a000, vmspace=0xfffffd807f00b000 estcpu=36, cpticks=56, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 51663 375988 68515 0 2 0 syz-executor.1 *51663 426146 68515 0 7 0x4000000 syz-executor.1 68515 344790 24130 0 3 0x82 nanoslp syz-executor.1 55752 71335 24130 0 2 0x2 syz-executor.0 24130 355099 75487 0 3 0x82 thrsleep syz-fuzzer 24130 178250 75487 0 3 0x4000082 nanoslp syz-fuzzer 24130 397611 75487 0 3 0x4000082 thrsleep syz-fuzzer 24130 470148 75487 0 3 0x4000082 thrsleep syz-fuzzer 24130 301800 75487 0 3 0x4000082 thrsleep syz-fuzzer 24130 51490 75487 0 3 0x4000082 kqread syz-fuzzer 75487 103744 81919 0 3 0x10008a sigsusp ksh 81919 373717 45462 0 3 0x92 select sshd 3021 365316 1 0 3 0x100083 ttyin getty 45462 92036 1 0 3 0x80 select sshd 85216 108289 40468 73 3 0x100090 kqread syslogd 40468 280156 1 0 3 0x100082 netio syslogd 4711 206142 1 77 3 0x100090 poll dhclient 22417 40809 1 0 3 0x80 poll dhclient 64569 498980 0 0 3 0x14200 bored smr 26232 85468 0 0 2 0x14200 zerothread 71144 23565 0 0 3 0x14200 aiodoned aiodoned 33979 143560 0 0 3 0x14200 syncer update 78562 468846 0 0 3 0x14200 cleaner cleaner 84022 424044 0 0 3 0x14200 reaper reaper 55234 229384 0 0 3 0x14200 pgdaemon pagedaemon 34757 519041 0 0 3 0x14200 bored crynlk 24761 449477 0 0 3 0x14200 bored crypto 89217 372777 0 0 3 0x14200 bored viomb 69859 473036 0 0 3 0x40014200 acpi0 acpi0 79861 429210 0 0 3 0x14200 bored softnet 97198 29053 0 0 3 0x14200 bored systqmp 45347 169537 0 0 3 0x14200 bored systq 36427 403312 0 0 3 0x40014200 bored softclock 51674 230362 0 0 3 0x40014200 idle0 1 346896 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 10100 6406K 6414K 78643K 11191 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 188 0 ifaddr 39 10K 10K 78643K 39 0 counters 21 16K 16K 78643K 21 0 ioctlops 0 0K 2K 78643K 15 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1215 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 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 12 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 21K 78643K 335 0 proc 47 38K 54K 78643K 354 0 subproc 32 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 19 95K 95K 78643K 19 0 exec 0 0K 2K 78643K 313 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 227 30K 30K 78643K 5137 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 5 0K 0K 78643K 9 0 temp 60 3967K 4031K 78643K 2418 0 kqueue 5 5K 5K 78643K 5 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 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 32 281 0 281 1 1 0 1 0 8 0 tcpcb 736 12 0 8 1 0 1 1 0 8 0 arp 88 6 0 0 1 0 1 1 0 8 0 inpcb 304 33 0 27 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 semupl 112 2 0 2 1 0 1 1 0 8 1 semapl 112 10 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1747 0 349 88 0 88 88 0 8 0 ffsino 240 1747 0 349 83 0 83 83 0 8 0 nchpl 144 2304 0 696 60 0 60 60 0 8 0 uvmvnodes 72 1790 0 0 33 0 33 33 0 8 0 vnodes 224 1790 0 0 106 0 106 106 0 8 0 namei 1024 5368 0 5367 2 1 1 1 0 8 0 scxspl 216 6583 0 6583 9 5 4 8 0 8 4 plimitpl 152 14 0 7 1 0 1 1 0 8 0 sigapl 424 521 0 492 4 0 4 4 0 8 0 futexpl 56 2743 0 2743 1 0 1 1 0 8 1 knotepl 112 64 0 42 1 0 1 1 0 8 0 kqueuepl 184 413 0 407 1 0 1 1 0 8 0 pipepl 304 112 0 101 2 0 2 2 0 8 1 fdescpl 432 506 0 492 2 0 2 2 0 8 0 filepl 120 1835 0 1735 4 0 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 48 0 41 1 0 1 1 0 8 0 zombiepl 144 492 0 492 2 1 1 1 0 8 1 processpl 1016 521 0 492 4 0 4 4 0 8 0 procpl 672 829 0 794 4 0 4 4 0 8 0 sockpl 448 75 0 59 2 0 2 2 0 8 0 mcl12k 12288 107 0 107 1 0 1 1 0 8 1 mcl9k 9216 12 0 12 1 0 1 1 0 8 1 mcl8k 8192 4 0 4 1 1 0 1 0 8 0 mcl4k 4096 6 0 6 2 1 1 1 0 8 1 mcl2k 2048 285068 0 285015 21 6 15 18 0 8 7 mtagpl 96 2 0 2 1 1 0 1 0 8 0 mbufpl 256 445617 0 445496 14 3 11 11 0 8 0 bufpl 280 3647 0 140 251 0 251 251 0 8 0 anonpl 24 136898 0 102041 212 2 210 210 0 188 0 amapchunkpl 152 12050 0 11152 37 1 36 36 0 158 1 amappl16 200 1961 0 575 74 1 73 73 0 8 0 amappl15 192 368 0 358 1 0 1 1 0 8 0 amappl14 184 5 0 2 1 0 1 1 0 8 0 amappl13 176 25 0 22 1 0 1 1 0 8 0 amappl12 168 8 0 6 1 0 1 1 0 8 0 amappl11 160 41 0 31 1 0 1 1 0 8 0 amappl10 152 35 0 29 1 0 1 1 0 8 0 amappl9 144 183 0 183 2 2 0 1 0 8 0 amappl8 136 296 0 257 2 0 2 2 0 8 0 amappl7 128 58 0 53 1 0 1 1 0 8 0 amappl6 120 97 0 83 1 0 1 1 0 8 0 amappl5 112 522 0 512 1 0 1 1 0 8 0 amappl4 104 457 0 432 1 0 1 1 0 8 0 amappl3 96 217 0 207 1 0 1 1 0 8 0 amappl2 88 625 0 580 3 1 2 2 0 8 0 amappl1 80 10796 0 10414 13 4 9 12 0 8 0 amappl 88 4778 0 4607 5 0 5 5 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 24 506 0 492 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 506 0 492 1 0 1 1 0 8 0 vmmpekpl 168 7142 0 7122 2 0 2 2 0 8 1 vmmpepl 168 57848 0 55273 150 1 149 149 0 357 37 vmsppl 272 505 0 492 2 0 2 2 0 8 1 rwobjpl 24 13236 0 11171 13 0 13 13 0 8 0 pdppl 4096 1018 0 984 56 18 38 38 0 8 4 pvpl 32 319613 0 280930 312 0 312 312 0 265 0 pmappl 200 505 0 492 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 295 0 32 8 0 8 8 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(fffffd806ea68620) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff80002272f4a0,fffffd806ea68620) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5fec38,ffff80002272f4a0,ffff800021661a40) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021661a40,ffff80002272f6b8,ffff80002272f710) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002272f780) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x18472358640, 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(fffffd806ea68620) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff80002272f4a0,fffffd806ea68620) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5fec38,ffff80002272f4a0,ffff800021661a40) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021661a40,ffff80002272f6b8,ffff80002272f710) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002272f780) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x18472358640, count: -8