panic: mutex 0xfffffd806e8aa6c0 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 411353 36702 0 0 0 1 syz-executor.0 *128607 36702 0 0 0x4000000 0K syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff82460c20) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e7a99a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000244d2f70,fffffd806e7a99a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff800021272d20,ffff8000244d3168,ffff8000244d31b0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000244d3230) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000244d3230) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x95a84b5f70, 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{0}> ddb{0}> set $lines = 0 ddb{0}> set $maxwidth = 0 ddb{0}> show panic *cpu0: mutex 0xfffffd806e8aa6c0 not held in knote_dequeue ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff82460c20) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e7a99a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000244d2f70,fffffd806e7a99a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff800021272d20,ffff8000244d3168,ffff8000244d31b0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000244d3230) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000244d3230) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x95a84b5f70, count: -8 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000244d2ca0 rbx 0xffffffff8275dbf7 cpu_info_full_primary+0x2bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff816e1c04 kprintf+0x144 r9 0x1 r10 0xcd70c66c2bf48ff6 r11 0xc7d24a21679a5333 r12 0xffffffff8275d9f8 cpu_info_full_primary+0x29f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81910f78 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000244d2c90 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.0) pid=128607 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800021272000,0xffffffff827da780 process=0xffff800021225d98 user=0xffff8000244ce000, vmspace=0xfffffd807f0095c0 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 36702 411353 81919 0 7 0 syz-executor.0 36702 292076 81919 0 2 0x4000080 syz-executor.0 *36702 128607 81919 0 7 0x4000000 syz-executor.0 74587 460662 0 0 3 0x14200 bored sosplice 88688 313084 78728 0 3 0x82 nanoslp syz-executor.1 81919 404650 78728 0 3 0x82 nanoslp syz-executor.0 78728 345587 81202 0 3 0x82 thrsleep syz-fuzzer 78728 197226 81202 0 3 0x4000082 nanoslp syz-fuzzer 78728 463482 81202 0 3 0x4000082 thrsleep syz-fuzzer 78728 434680 81202 0 3 0x4000082 thrsleep syz-fuzzer 78728 384702 81202 0 3 0x4000082 kqread syz-fuzzer 78728 483375 81202 0 3 0x4000082 thrsleep syz-fuzzer 78728 159757 81202 0 3 0x4000082 thrsleep syz-fuzzer 78728 197017 81202 0 3 0x4000082 thrsleep syz-fuzzer 81202 462106 70895 0 3 0x10008a sigsusp ksh 70895 189030 5885 0 3 0x92 select sshd 61346 245779 1 0 3 0x100083 ttyin getty 5885 201469 1 0 3 0x80 select sshd 13561 481529 20902 74 3 0x100092 bpf pflogd 20902 63553 1 0 3 0x80 netio pflogd 44065 442980 39782 73 3 0x100090 kqread syslogd 39782 232037 1 0 3 0x100082 netio syslogd 12719 231821 1 77 3 0x100090 poll dhclient 79833 122523 1 0 3 0x80 poll dhclient 85999 434768 0 0 3 0x14200 bored smr 91765 490433 0 0 2 0x14200 zerothread 57244 360987 0 0 3 0x14200 aiodoned aiodoned 35907 410538 0 0 3 0x14200 syncer update 58334 112583 0 0 3 0x14200 cleaner cleaner 91350 263732 0 0 3 0x14200 reaper reaper 22821 503266 0 0 3 0x14200 pgdaemon pagedaemon 94316 57860 0 0 3 0x14200 bored crynlk 55401 374509 0 0 3 0x14200 bored crypto 72247 73227 0 0 3 0x14200 bored viomb 28746 177813 0 0 3 0x40014200 acpi0 acpi0 53050 346765 0 0 3 0x40014200 idle1 40169 34770 0 0 3 0x14200 bored softnet 63078 31883 0 0 3 0x14200 bored systqmp 38208 376820 0 0 3 0x14200 bored systq 20203 365161 0 0 3 0x40014200 bored softclock 21646 221312 0 0 3 0x40014200 idle0 1 288597 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 36702 (syz-executor.0) thread 0xffff800021272d20 (128607) exclusive kernel_lock &kernel_lock r = 1 (0xffffffff827d4278) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 syscall+0x439 mi_syscall sys/sys/syscall_mi.h:93 [inline] #1 syscall+0x439 sys/arch/amd64/amd64/trap.c:587 #2 Xsyscall+0x128 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10129 6484K 7000K 78643K 11548 0 pcb 13 8K 8K 78643K 44 0 rtable 105 3K 3K 78643K 218 0 ifaddr 49 11K 11K 78643K 67 0 counters 44 34K 34K 78643K 52 0 ioctlops 0 0K 4K 78643K 1507 0 iov 0 0K 8K 78643K 12 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1221 77K 77K 78643K 1341 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 12 0K 0K 78643K 87 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 442 0 proc 62 63K 83K 78643K 457 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 49 0 ether_multi 1 0K 0K 78643K 5 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 354 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 212 93K 94K 78643K 6698 0 UVM aobj 3 2K 2K 78643K 14 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 7 0K 0K 78643K 15 0 temp 104 3984K 4048K 78643K 3037 0 kqueue 5 5K 8K 78643K 10 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 plcache 128 22 0 0 1 0 1 1 0 8 0 rtpcb 120 24 0 22 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 126 0 116 1 0 1 1 0 8 0 syncache 296 8 0 8 2 2 0 1 0 8 0 tcpqe 32 122 0 122 1 1 0 1 0 8 0 tcpcb 736 67 0 63 3 1 2 2 0 8 1 arp 120 6 0 0 1 0 1 1 0 8 0 inpcb 304 176 0 170 2 1 1 2 0 8 0 nd6 48 6 0 0 1 0 1 1 0 8 0 pkpcb 40 10 0 10 1 1 0 1 0 8 0 kcovpl 48 2 0 0 1 0 1 1 0 8 0 swfcl 56 4 0 0 1 0 1 1 0 8 0 ppxss 1128 4 0 4 1 1 0 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 15 0 5 1 0 1 1 0 8 0 pfstkey 112 15 0 5 1 0 1 1 0 8 0 pfstate 320 15 0 5 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 sysvmsgpl 40 7 0 7 1 0 1 1 0 8 1 semupl 112 6 0 6 1 1 0 1 0 8 0 semapl 112 79 0 69 1 0 1 1 0 8 0 shmpl 112 11 0 11 1 1 0 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1893 0 486 89 0 89 89 0 8 1 ffsino 272 1893 0 486 94 0 94 94 0 8 0 nchpl 144 2584 0 968 63 3 60 61 0 8 0 uvmvnodes 72 2022 0 0 37 0 37 37 0 8 0 vnodes 224 2022 0 0 119 0 119 119 0 8 0 namei 1024 6417 0 6417 1 0 1 1 0 8 1 percpumem 16 38 0 4 1 0 1 1 0 8 0 vcpupl 1984 5 0 0 1 0 1 1 0 8 0 vmpool 560 5 0 0 1 0 1 1 0 8 0 scxspl 216 7578 0 7578 10 8 2 8 0 8 2 plimitpl 152 30 0 22 1 0 1 1 0 8 0 sigapl 424 658 0 625 4 0 4 4 0 8 0 futexpl 56 3118 0 3118 2 1 1 1 0 8 1 knotepl 112 32 0 0 1 0 1 1 0 8 0 kqueuepl 216 161 0 158 1 0 1 1 0 8 0 pipepl 336 101 0 90 4 2 2 2 0 8 1 fdescpl 496 641 0 625 3 0 3 3 0 8 0 filepl 152 2279 0 2177 6 1 5 5 0 8 1 lockfpl 104 65 0 64 1 0 1 1 0 8 0 lockfspl 48 24 0 23 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 96 208 0 199 1 0 1 1 0 8 0 zombiepl 144 625 0 624 2 1 1 1 0 8 0 processpl 1080 658 0 624 3 0 3 3 0 8 0 procpl 672 1184 0 1141 4 0 4 4 0 8 0 sockpl 480 341 0 323 4 1 3 4 0 8 0 mcl64k 65536 6 0 0 1 0 1 1 0 8 0 mcl16k 16384 8 0 0 1 0 1 1 0 8 0 mcl12k 12288 9 0 0 1 0 1 1 0 8 0 mcl8k 8192 6 0 0 1 0 1 1 0 8 0 mcl4k 4096 7 0 0 1 0 1 1 0 8 0 mcl2k 2048 157 0 0 19 0 19 19 0 8 0 mtagpl 96 12 0 0 1 0 1 1 0 8 0 mbufpl 256 175 0 0 11 0 11 11 0 8 0 bufpl 280 3865 0 149 266 0 266 266 0 8 0 anonpl 24 149685 0 133616 102 3 99 99 0 186 1 amapchunkpl 152 15655 0 15098 26 3 23 24 0 158 0 amappl16 200 1338 0 766 32 1 31 31 0 8 0 amappl15 192 61 0 54 1 0 1 1 0 8 0 amappl14 184 4 0 2 1 0 1 1 0 8 0 amappl13 176 30 0 27 1 0 1 1 0 8 0 amappl12 168 220 0 216 1 0 1 1 0 8 0 amappl11 160 42 0 29 1 0 1 1 0 8 0 amappl10 152 42 0 32 1 0 1 1 0 8 0 amappl9 144 435 0 434 3 2 1 1 0 8 0 amappl8 136 328 0 288 2 0 2 2 0 8 0 amappl7 128 65 0 57 1 0 1 1 0 8 0 amappl6 120 318 0 303 1 0 1 1 0 8 0 amappl5 112 333 0 322 1 0 1 1 0 8 0 amappl4 104 550 0 515 3 1 2 2 0 8 0 amappl3 96 336 0 324 1 0 1 1 0 8 0 amappl2 88 981 0 933 2 0 2 2 0 8 0 amappl1 80 13189 0 12766 13 3 10 12 0 8 0 amappl 88 6394 0 6245 4 0 4 4 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 13 0 11 1 0 1 1 0 8 0 uaddrrnd 24 646 0 625 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 646 0 625 1 0 1 1 0 8 0 vmmpekpl 168 8035 0 8001 2 0 2 2 0 8 0 vmmpepl 168 70216 0 68369 101 16 85 100 0 357 0 vmsppl 368 645 0 625 2 0 2 2 0 8 0 rwobjpl 56 14862 0 13576 21 2 19 19 0 8 0 pdppl 4096 1299 0 1255 64 17 47 47 0 8 3 pvpl 32 382192 0 362918 167 3 164 164 0 265 7 pmappl 232 645 0 625 3 1 2 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 312 0 23 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:399 panic(ffffffff82460c20) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e7a99a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000244d2f70,fffffd806e7a99a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8aa6c0,ffff8000244d2f70,ffff800021272d20) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff800021272d20,ffff8000244d3168,ffff8000244d31b0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000244d3230) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000244d3230) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x95a84b5f70, count: -8 ddb{0}> machine ddbcpu 1 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffff800020d58ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:353 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 syscall(ffff8000244cda50) at syscall+0x30f Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc9830, count: 10 ddb{1}> trace x86_ipi_db(ffff800020d58ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:353 x86_ipi_handler() at x86_ipi_handler+0xb7 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23 syscall(ffff8000244cda50) at syscall+0x30f Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc9830, count: -5