panic: mutex 0xfffffd806e5ffb80 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *458613 99188 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(fffffd806fc2f1c0) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800024733500,fffffd806fc2f1c0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5ffb80,ffff800024733500,ffff80002168da48) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff80002168da48,ffff8000247336f8,ffff800024733750) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000247337c0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xff3b4c21da0, 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 0xfffffd806e5ffb80 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(fffffd806fc2f1c0) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800024733500,fffffd806fc2f1c0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5ffb80,ffff800024733500,ffff80002168da48) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff80002168da48,ffff8000247336f8,ffff800024733750) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000247337c0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xff3b4c21da0, count: -8 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff800024733230 rbx 0 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81d4e795 kprintf+0x145 r9 0x1 r10 0x2382596c13acadf6 r11 0x2b0c0e9584296dcc r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff81dfed58 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800024733220 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb> show proc PROC (syz-executor.1) pid=458613 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=80, nice=20 forw=0xffffffffffffffff, list=0xffff80002168c7e8,0xffff80002168d278 process=0xffff80002168b410 user=0xffff80002472e000, vmspace=0xfffffd80669bf890 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 81801 342589 1615 0 2 0 syz-executor.0 81801 381712 1615 0 3 0x4000080 fsleep syz-executor.0 99188 254451 6572 0 2 0 syz-executor.1 *99188 458613 6572 0 7 0x4000000 syz-executor.1 6572 495351 46819 0 3 0x82 nanoslp syz-executor.1 69715 170586 1 0 3 0x100083 ttyin getty 21911 181938 0 0 3 0x14280 nfsidl nfsio 97679 182829 0 0 3 0x14280 nfsidl nfsio 97701 508156 0 0 3 0x14280 nfsidl nfsio 99177 73191 0 0 3 0x14280 nfsidl nfsio 58048 424491 0 0 3 0x14280 nfsidl nfsio 31331 108097 0 0 3 0x14280 nfsidl nfsio 99454 512808 0 0 3 0x14280 nfsidl nfsio 80338 463978 0 0 3 0x14280 nfsidl nfsio 85238 263567 0 0 3 0x14280 nfsidl nfsio 71930 492184 0 0 3 0x14280 nfsidl nfsio 73943 339580 0 0 3 0x14280 nfsidl nfsio 80309 344264 0 0 3 0x14280 nfsidl nfsio 97194 27480 0 0 3 0x14280 nfsidl nfsio 14031 174599 0 0 3 0x14280 nfsidl nfsio 81618 63186 0 0 3 0x14280 nfsidl nfsio 67281 415975 0 0 3 0x14280 nfsidl nfsio 16362 435533 0 0 3 0x14280 nfsidl nfsio 99316 304437 0 0 3 0x14280 nfsidl nfsio 98780 26213 0 0 3 0x14280 nfsidl nfsio 81114 475074 0 0 3 0x14280 nfsidl nfsio 28408 448799 0 0 3 0x14200 acct acct 1615 345974 46819 0 3 0x82 nanoslp syz-executor.0 68450 147500 0 0 3 0x14200 bored sosplice 46819 70008 19724 0 3 0x82 thrsleep syz-fuzzer 46819 5717 19724 0 3 0x4000082 thrsleep syz-fuzzer 46819 405675 19724 0 3 0x4000082 kqread syz-fuzzer 46819 120048 19724 0 3 0x4000082 thrsleep syz-fuzzer 46819 515173 19724 0 3 0x4000082 thrsleep syz-fuzzer 46819 178955 19724 0 3 0x4000082 thrsleep syz-fuzzer 46819 237142 19724 0 3 0x4000082 thrsleep syz-fuzzer 19724 349220 73786 0 3 0x10008a sigsusp ksh 73786 229579 21588 0 3 0x92 select sshd 21588 57697 1 0 3 0x80 select sshd 77755 220990 18250 73 3 0x100090 kqread syslogd 18250 503733 1 0 3 0x100082 netio syslogd 22208 322392 1 77 3 0x100090 poll dhclient 52303 294608 1 0 3 0x80 poll dhclient 1001 1953 0 0 3 0x14200 bored smr 63247 388206 0 0 2 0x14200 zerothread 60635 141268 0 0 3 0x14200 aiodoned aiodoned 44262 499193 0 0 3 0x14200 syncer update 41420 460551 0 0 3 0x14200 cleaner cleaner 89371 131628 0 0 3 0x14200 reaper reaper 12973 188862 0 0 3 0x14200 pgdaemon pagedaemon 98883 35977 0 0 3 0x14200 bored crynlk 9112 73643 0 0 3 0x14200 bored crypto 75113 489166 0 0 3 0x14200 bored viomb 353 45927 0 0 3 0x40014200 acpi0 acpi0 1692 200247 0 0 3 0x14200 bored softnet 49427 263682 0 0 3 0x14200 bored systqmp 29909 189408 0 0 3 0x14200 bored systq 78739 144395 0 0 3 0x40014200 bored softclock 73167 159768 0 0 3 0x40014200 idle0 1 137116 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 10183 6446K 7610K 78643K 17927 0 pcb 13 8K 8K 78643K 328 0 rtable 106 12K 13K 78643K 927 0 ifaddr 80 14K 15K 78643K 303 0 sysctl 2 0K 0K 78643K 2 0 counters 21 16K 16K 78643K 52 0 ioctlops 0 0K 4K 78643K 200 0 iov 0 0K 16K 78643K 177 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1229 77K 78K 78643K 3469 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 9K 78643K 27 0 VM map 2 0K 0K 78643K 2 0 sem 12 0K 0K 78643K 860 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 6 17K 25K 78643K 6463 0 sigio 0 0K 0K 78643K 61 0 proc 51 38K 62K 78643K 627 0 subproc 32 2K 2K 78643K 85 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 479 0 in_multi 32 2K 2K 78643K 282 0 ether_multi 1 0K 0K 78643K 99 0 mrt 0 0K 0K 78643K 61 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 67 307K 307K 78643K 67 0 exec 0 0K 2K 78643K 507 0 pfkey data 0 0K 0K 78643K 8 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 236 98K 100K 78643K 76933 0 UVM aobj 21 2K 2K 78643K 37 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 1K 78643K 353 0 NDP 15 0K 0K 78643K 56 0 temp 142 3980K 4106K 78643K 32524 0 kqueue 7 7K 24K 78643K 456 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 120 333 0 331 1 0 1 1 0 8 0 rtentry 112 118 0 78 2 0 2 2 0 8 0 unpcb 120 1232 0 1224 1 0 1 1 0 8 0 syncache 296 50 0 50 6 6 0 1 0 8 0 tcpqe 32 88 0 88 4 3 1 1 0 8 1 tcpcb 736 848 0 831 21 16 5 5 0 8 0 arp 88 13 0 9 1 0 1 1 0 8 0 ipq 40 5 0 5 1 1 0 1 0 8 0 ipqe 40 10 0 10 1 1 0 1 0 8 0 inpcb 304 2357 0 2338 3 1 2 2 0 8 0 rttmr 72 15 0 15 2 2 0 1 0 8 0 ip6q 72 3 0 3 1 1 0 1 0 8 0 ip6af 40 5 0 5 1 1 0 1 0 8 0 nd6 48 16 0 10 1 0 1 1 0 8 0 pkpcb 40 58 0 58 7 7 0 1 0 8 0 kcovpl 48 5 0 3 1 0 1 1 0 8 0 swfcl 56 4 0 0 1 0 1 1 0 8 0 ppxss 1128 19 0 19 4 4 0 1 0 8 0 pfrktable 1344 86 0 85 2 1 1 1 0 8 0 pftag 88 36 0 17 2 1 1 1 0 8 0 pfqueue 264 19 0 18 2 1 1 1 0 8 0 pfrule 1360 47 0 37 2 1 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 383 0 193 15 3 12 15 0 8 0 art_table 32 384 0 193 2 0 2 2 0 8 0 art_node 16 102 0 66 1 0 1 1 0 8 0 sysvmsgpl 40 39 0 14 1 0 1 1 0 8 0 semapl 112 858 0 848 1 0 1 1 0 8 0 shmpl 112 34 0 16 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 9525 0 8130 88 0 88 88 0 8 0 ffsino 240 9525 0 8130 83 0 83 83 0 8 0 nchpl 144 17162 0 15565 60 0 60 60 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 224 5926 0 0 349 0 349 349 0 8 0 namei 1024 41450 0 41450 1 0 1 1 0 8 1 vcpupl 1984 4 0 0 1 0 1 1 0 8 0 vmpool 528 4 0 0 1 0 1 1 0 8 0 pfiaddrpl 120 17 0 17 1 1 0 1 0 8 0 scsiplug 72 4 0 4 1 0 1 1 0 8 1 scxspl 216 51624 0 51624 13 12 1 8 0 8 1 plimitpl 152 97 0 90 1 0 1 1 0 8 0 sigapl 424 6663 0 6611 6 0 6 6 0 8 0 futexpl 56 54740 0 54739 1 0 1 1 0 8 0 knotepl 112 1076 0 1052 2 1 1 2 0 8 0 kqueuepl 184 3511 0 3490 8 6 2 2 0 8 1 pipepl 304 415 0 404 12 11 1 2 0 8 0 fdescpl 432 6626 0 6611 2 0 2 2 0 8 0 filepl 120 21970 0 21872 5 1 4 4 0 8 1 lockfpl 104 995 0 993 1 0 1 1 0 8 0 lockfspl 48 385 0 383 1 0 1 1 0 8 0 sessionpl 144 21 0 11 1 0 1 1 0 8 0 pgrppl 48 37 0 27 1 0 1 1 0 8 0 ucredpl 96 2376 0 2369 1 0 1 1 0 8 0 zombiepl 144 6611 0 6611 1 0 1 1 0 8 1 processpl 1016 6663 0 6611 8 1 7 7 0 8 0 procpl 672 13463 0 13403 8 2 6 6 0 8 0 sosppl 168 80 0 80 7 6 1 1 0 8 1 sockpl 448 4004 0 3975 13 9 4 5 0 8 0 mcl64k 65536 143 0 142 4 3 1 1 0 8 0 mcl16k 16384 47 0 47 6 6 0 1 0 8 0 mcl12k 12288 149 0 149 12 12 0 1 0 8 0 mcl9k 9216 70 0 69 4 3 1 1 0 8 0 mcl8k 8192 83 0 83 11 11 0 1 0 8 0 mcl4k 4096 251 0 251 11 11 0 1 0 8 0 mcl2k2 2112 34 0 34 6 6 0 1 0 8 0 mcl2k 2048 61030 0 60960 72 54 18 18 0 8 7 mtagpl 96 548 0 392 11 1 10 10 0 8 0 mbufpl 256 251892 0 251341 98 33 65 69 0 8 0 bufpl 280 12829 0 6438 457 0 457 457 0 8 0 anonpl 24 1734369 0 1723693 167 89 78 95 0 188 12 amapchunkpl 152 182239 0 181843 32 16 16 26 0 158 0 amappl16 200 17483 0 17102 74 53 21 36 0 8 0 amappl15 192 159 0 149 1 0 1 1 0 8 0 amappl14 184 6 0 2 1 0 1 1 0 8 0 amappl13 176 3239 0 3238 1 0 1 1 0 8 0 amappl12 168 1272 0 1269 1 0 1 1 0 8 0 amappl11 160 253 0 245 1 0 1 1 0 8 0 amappl10 152 41 0 33 1 0 1 1 0 8 0 amappl9 144 1937 0 1934 1 0 1 1 0 8 0 amappl8 136 452 0 380 3 0 3 3 0 8 0 amappl7 128 69 0 64 1 0 1 1 0 8 0 amappl6 120 1824 0 1806 1 0 1 1 0 8 0 amappl5 112 5076 0 5064 1 0 1 1 0 8 0 amappl4 104 1011 0 982 1 0 1 1 0 8 0 amappl3 96 1583 0 1575 1 0 1 1 0 8 0 amappl2 88 11211 0 11162 2 0 2 2 0 8 0 amappl1 80 103471 0 103072 12 3 9 12 0 8 0 amappl 88 76073 0 75937 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 36 0 16 1 0 1 1 0 8 0 uaddrrnd 24 6630 0 6611 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 6630 0 6611 1 0 1 1 0 8 0 vmmpekpl 168 32167 0 32133 2 0 2 2 0 8 0 vmmpepl 168 739771 0 738089 133 51 82 88 0 357 7 vmsppl 272 6629 0 6611 3 1 2 2 0 8 0 rwobjpl 24 127029 0 125977 12 5 7 8 0 8 0 pdppl 4096 13266 0 13226 55 15 40 40 0 8 0 pvpl 32 3666999 0 3653016 291 148 143 162 0 265 28 pmappl 200 6629 0 6611 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 498 0 166 10 0 10 10 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(fffffd806fc2f1c0) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800024733500,fffffd806fc2f1c0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5ffb80,ffff800024733500,ffff80002168da48) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff80002168da48,ffff8000247336f8,ffff800024733750) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000247337c0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xff3b4c21da0, 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(fffffd806fc2f1c0) at knote_dequeue+0x129 sys/kern/kern_event.c:1860 filt_timermodify(ffff800024733500,fffffd806fc2f1c0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e5ffb80,ffff800024733500,ffff80002168da48) at kqueue_register+0x9f2 sys/kern/kern_event.c:1125 sys_kevent(ffff80002168da48,ffff8000247336f8,ffff800024733750) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000247337c0) at syscall+0x577 sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xff3b4c21da0, count: -8