panic: mutex 0xfffffd806e600cf0 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *338629 83638 0 0x2 0 0 syz-executor0839 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(fffffd806eb18690) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff8000216b5030,fffffd806eb18690) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e600cf0,ffff8000216b5030,ffff800021686a90) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021686a90,ffff8000216b5228,ffff8000216b5280) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000216b52f0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe58b0, 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 0xfffffd806e600cf0 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(fffffd806eb18690) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff8000216b5030,fffffd806eb18690) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e600cf0,ffff8000216b5030,ffff800021686a90) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021686a90,ffff8000216b5228,ffff8000216b5280) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000216b52f0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe58b0, count: -8 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff8000216b4d60 rbx 0 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81d4e795 kprintf+0x145 r9 0x1 r10 0xe7b11a178d7d58b8 r11 0x45f3030158ed6e2e r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff81dfed58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000216b4d50 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor0839) pid=338629 stat=onproc flags process=2 proc=0 pri=52, usrpri=53, nice=20 forw=0xffffffffffffffff, list=0xffff800021686010,0xffffffff82868538 process=0xffff800021688808 user=0xffff8000216b0000, vmspace=0xfffffd807f00b330 estcpu=3, cpticks=4, pctcpu=0.0 user=0, sys=4, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND *83638 338629 67514 0 7 0x2 syz-executor0839 67514 508246 47452 0 3 0x10008a sigsusp ksh 47452 333529 48838 0 3 0x92 select sshd 54891 256189 1 0 3 0x100083 ttyin getty 48838 389339 1 0 3 0x80 select sshd 10488 81084 30108 73 3 0x100090 kqread syslogd 30108 55320 1 0 3 0x100082 netio syslogd 64343 53983 1 77 3 0x100090 poll dhclient 43173 31614 1 0 3 0x80 poll dhclient 93962 330917 0 0 3 0x14200 bored smr 94284 376252 0 0 2 0x14200 zerothread 76957 99741 0 0 3 0x14200 aiodoned aiodoned 77570 9849 0 0 3 0x14200 syncer update 20225 211192 0 0 3 0x14200 cleaner cleaner 19361 36617 0 0 3 0x14200 reaper reaper 6090 59433 0 0 3 0x14200 pgdaemon pagedaemon 79295 391532 0 0 3 0x14200 bored crynlk 37116 131214 0 0 3 0x14200 bored crypto 66845 125502 0 0 3 0x14200 bored viomb 45285 454058 0 0 3 0x40014200 acpi0 acpi0 38111 65569 0 0 3 0x14200 bored softnet 5899 345758 0 0 3 0x14200 bored systqmp 86066 71787 0 0 3 0x14200 bored systq 21495 377619 0 0 3 0x40014200 bored softclock 3013 344753 0 0 3 0x40014200 idle0 1 282739 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 10094 6402K 6403K 78643K 11184 0 pcb 13 8K 8K 78643K 13 0 rtable 61 2K 2K 78643K 111 0 ifaddr 24 7K 7K 78643K 24 0 counters 19 16K 16K 78643K 19 0 ioctlops 0 0K 2K 78643K 13 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1182 74K 74K 78643K 1187 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 2 0K 0K 78643K 2 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 1 0K 0K 78643K 1 0 proc 47 38K 46K 78643K 274 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 11 0K 0K 78643K 11 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 257 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 58 2K 4K 78643K 1171 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 3 0K 0K 78643K 3 0 temp 18 3965K 4029K 78643K 1430 0 kqueue 4 3K 3K 78643K 4 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 15 0 13 1 0 1 1 0 8 0 rtentry 112 23 0 1 1 0 1 1 0 8 0 unpcb 120 27 0 19 1 0 1 1 0 8 0 syncache 296 5 0 5 1 0 1 1 0 8 1 tcpqe 32 1 0 1 1 1 0 1 0 8 0 tcpcb 736 8 0 4 1 0 1 1 0 8 0 arp 88 2 0 0 1 0 1 1 0 8 0 inpcb 304 21 0 15 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 96 0 0 6 0 6 6 0 8 0 art_table 32 97 0 0 1 0 1 1 0 8 0 art_node 16 22 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1392 0 15 87 0 87 87 0 8 0 ffsino 240 1392 0 15 81 0 81 81 0 8 0 nchpl 144 1568 0 31 57 0 57 57 0 8 0 uvmvnodes 72 1401 0 0 26 0 26 26 0 8 0 vnodes 224 1401 0 0 83 0 83 83 0 8 0 namei 1024 3484 0 3484 1 0 1 1 0 8 1 scxspl 216 3172 0 3172 3 2 1 2 0 8 1 plimitpl 152 13 0 8 1 0 1 1 0 8 0 sigapl 424 191 0 165 4 0 4 4 0 8 0 knotepl 112 7 0 0 1 0 1 1 0 8 0 kqueuepl 184 2 0 0 1 0 1 1 0 8 0 pipepl 304 57 0 53 1 0 1 1 0 8 0 fdescpl 432 176 0 165 2 0 2 2 0 8 0 filepl 120 820 0 777 2 0 2 2 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 9 1 0 1 1 0 8 0 pgrppl 48 17 0 9 1 0 1 1 0 8 0 ucredpl 96 57 0 50 1 0 1 1 0 8 0 zombiepl 144 165 0 165 1 0 1 1 0 8 1 processpl 1016 191 0 165 4 0 4 4 0 8 0 procpl 672 191 0 165 3 0 3 3 0 8 0 sockpl 448 63 0 47 2 0 2 2 0 8 0 mcl8k 8192 5 0 5 1 0 1 1 0 8 1 mcl4k 4096 5 0 5 1 0 1 1 0 8 1 mcl2k 2048 5236 0 5199 8 1 7 8 0 8 1 mtagpl 96 2 0 2 1 1 0 1 0 8 0 mbufpl 256 8991 0 8946 6 1 5 6 0 8 0 bufpl 280 1845 0 84 126 0 126 126 0 8 0 anonpl 24 25270 0 23148 14 1 13 13 0 188 0 amapchunkpl 152 2206 0 2107 5 0 5 5 0 158 0 amappl16 200 55 0 27 3 1 2 2 0 8 0 amappl15 192 43 0 38 1 0 1 1 0 8 0 amappl13 176 12 0 11 1 0 1 1 0 8 0 amappl12 168 3 0 3 1 0 1 1 0 8 1 amappl11 160 38 0 30 1 0 1 1 0 8 0 amappl10 152 27 0 22 1 0 1 1 0 8 0 amappl9 144 177 0 177 1 1 0 1 0 8 0 amappl8 136 196 0 192 1 0 1 1 0 8 0 amappl7 128 38 0 37 1 0 1 1 0 8 0 amappl6 120 71 0 62 1 0 1 1 0 8 0 amappl5 112 150 0 143 1 0 1 1 0 8 0 amappl4 104 424 0 401 1 0 1 1 0 8 0 amappl3 96 80 0 73 1 0 1 1 0 8 0 amappl2 88 261 0 228 1 0 1 1 0 8 0 amappl1 80 5918 0 5597 8 0 8 8 0 8 0 amappl 88 997 0 953 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 24 176 0 165 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 176 0 165 1 0 1 1 0 8 0 vmmpekpl 168 5135 0 5119 1 0 1 1 0 8 0 vmmpepl 168 17570 0 16853 36 1 35 35 0 357 3 vmsppl 272 175 0 165 1 0 1 1 0 8 0 rwobjpl 24 5500 0 5035 3 0 3 3 0 8 0 pdppl 4096 358 0 330 38 10 28 34 0 8 0 pvpl 32 85359 0 81669 30 0 30 30 0 265 0 pmappl 200 175 0 165 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 244 0 14 7 0 7 7 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(fffffd806eb18690) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff8000216b5030,fffffd806eb18690) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e600cf0,ffff8000216b5030,ffff800021686a90) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021686a90,ffff8000216b5228,ffff8000216b5280) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000216b52f0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe58b0, 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(fffffd806eb18690) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff8000216b5030,fffffd806eb18690) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e600cf0,ffff8000216b5030,ffff800021686a90) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff800021686a90,ffff8000216b5228,ffff8000216b5280) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000216b52f0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffe58b0, count: -8 ddb>