panic: mutex 0xfffffd806e8b3438 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 66961 80596 0 0 0 1 syz-executor.0 *212258 33388 0 0 0x4000000 0K syz-executor.1 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(fffffd806e7b0230) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000222cf6e0,fffffd806e7b0230) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002129b7a8,ffff8000222cf998,ffff8000222cf9e0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000222cfa60) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222cfa60) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2f7949ad080, 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 0xfffffd806e8b3438 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(fffffd806e7b0230) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000222cf6e0,fffffd806e7b0230) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002129b7a8,ffff8000222cf998,ffff8000222cf9e0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000222cfa60) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222cfa60) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2f7949ad080, count: -8 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000222cf4d0 rbx 0xffffffff8275dbf7 cpu_info_full_primary+0x2bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff816e1c04 kprintf+0x144 r9 0x1 r10 0x27acacb96e66293b r11 0x150ce241f7a626c6 r12 0xffffffff8275d9f8 cpu_info_full_primary+0x29f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81910f78 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000222cf4c0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=212258 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff80002129a548,0xffff80002129ad38 process=0xffff800021226608 user=0xffff8000222ca000, vmspace=0xfffffd806e8e3a18 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 80596 66961 89042 0 7 0 syz-executor.0 33388 4041 32833 0 2 0 syz-executor.1 33388 215801 32833 0 3 0x4000080 fsleep syz-executor.1 *33388 212258 32833 0 7 0x4000000 syz-executor.1 32833 451802 72826 0 3 0x82 nanoslp syz-executor.1 89042 80646 72826 0 3 0x82 nanoslp syz-executor.0 72826 5989 84794 0 3 0x82 thrsleep syz-fuzzer 72826 296537 84794 0 3 0x4000082 nanoslp syz-fuzzer 72826 183572 84794 0 3 0x4000082 thrsleep syz-fuzzer 72826 130453 84794 0 3 0x4000082 thrsleep syz-fuzzer 72826 79387 84794 0 3 0x4000082 thrsleep syz-fuzzer 72826 347675 84794 0 3 0x4000082 thrsleep syz-fuzzer 72826 496300 84794 0 3 0x4000082 kqread syz-fuzzer 72826 185415 84794 0 3 0x4000082 thrsleep syz-fuzzer 84794 328618 35486 0 3 0x10008a sigsusp ksh 35486 410286 95755 0 3 0x92 select sshd 67087 468802 1 0 3 0x100083 ttyin getty 95755 341937 1 0 3 0x80 select sshd 42149 463783 15922 74 3 0x100092 bpf pflogd 15922 154137 1 0 3 0x80 netio pflogd 34364 285322 46094 73 3 0x100090 kqread syslogd 46094 297774 1 0 3 0x100082 netio syslogd 38234 506462 1 77 3 0x100090 poll dhclient 6812 17008 1 0 3 0x80 poll dhclient 80042 341069 0 0 3 0x14200 bored smr 83749 420439 0 0 2 0x14200 zerothread 27759 134870 0 0 3 0x14200 aiodoned aiodoned 72721 29538 0 0 3 0x14200 syncer update 16960 26463 0 0 3 0x14200 cleaner cleaner 16159 490528 0 0 3 0x14200 reaper reaper 8679 407974 0 0 3 0x14200 pgdaemon pagedaemon 85304 86404 0 0 3 0x14200 bored crynlk 37222 286988 0 0 3 0x14200 bored crypto 74154 223247 0 0 3 0x14200 bored viomb 82739 183013 0 0 3 0x40014200 acpi0 acpi0 65125 116212 0 0 3 0x40014200 idle1 77306 93186 0 0 3 0x14200 bored softnet 33700 61543 0 0 3 0x14200 bored systqmp 23646 176224 0 0 3 0x14200 bored systq 88629 478699 0 0 3 0x40014200 bored softclock 32817 104197 0 0 3 0x40014200 idle0 1 216886 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 80596 (syz-executor.0) thread 0xffff80002129ad28 (66961) exclusive rwlock amaplk r = 0 (0xfffffd8062109ac8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 uvm_fault_check+0x3de sys/uvm/uvm_fault.c:774 #2 uvm_fault+0x102 sys/uvm/uvm_fault.c:601 #3 upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 #4 usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 #5 recall_trap+0x8 shared rwlock vmmaplk r = 0 (0xfffffd806e8e3ba0) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 uvmfault_lookup+0xd9 sys/uvm/uvm_fault.c:1701 #2 uvm_fault_check+0x3a sys/uvm/uvm_fault.c:674 #3 uvm_fault+0x102 sys/uvm/uvm_fault.c:601 #4 upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 #5 usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 #6 recall_trap+0x8 Process 33388 (syz-executor.1) thread 0xffff80002129b7a8 (212258) 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 10120 6476K 6675K 78643K 42956 0 pcb 13 8K 8K 78643K 37 0 rtable 105 3K 3K 78643K 195 0 ifaddr 44 10K 10K 78643K 45 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 4K 78643K 1469 0 iov 0 0K 12K 78643K 20 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1233 78K 78K 78643K 27706 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 5 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 44 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 6 17K 25K 78643K 54339 0 sigio 0 0K 0K 78643K 296 0 proc 60 63K 95K 78643K 448 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 31 148K 148K 78643K 31 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 283 36K 37K 78643K 636751 0 UVM aobj 12 2K 2K 78643K 14 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 9 0 NDP 6 0K 0K 78643K 10 0 temp 66 3975K 4039K 78643K 137219 0 kqueue 7 6K 9K 78643K 24 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 29 0 27 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 768 0 758 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 891 0 891 1 1 0 1 0 8 0 tcpcb 736 59 0 49 3 2 1 2 0 8 0 arp 120 6 0 0 1 0 1 1 0 8 0 inpcb 304 121 0 115 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 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 11 0 9 1 0 1 1 0 8 0 pfstkey 112 11 0 9 1 0 1 1 0 8 0 pfstate 320 11 0 9 1 0 1 1 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 256 189 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 semapl 112 42 0 32 1 0 1 1 0 8 0 shmpl 112 11 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 55779 0 54373 91 3 88 89 0 8 0 ffsino 272 55779 0 54373 94 0 94 94 0 8 0 nchpl 144 111658 0 110041 64 3 61 61 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 262553 0 262553 2 1 1 1 0 8 1 percpumem 16 34 0 0 1 0 1 1 0 8 0 scxspl 216 331110 0 331110 9 8 1 8 0 8 1 plimitpl 152 17 0 9 1 0 1 1 0 8 0 sigapl 424 54554 0 54521 4 0 4 4 0 8 0 futexpl 56 265553 0 265552 1 0 1 1 0 8 0 knotepl 112 34 0 0 1 0 1 1 0 8 0 kqueuepl 216 61794 0 61786 1 0 1 1 0 8 0 pipepl 336 3482 0 3471 9 7 2 2 0 8 1 fdescpl 496 54538 0 54521 3 0 3 3 0 8 0 filepl 152 165719 0 165616 14 9 5 5 0 8 1 lockfpl 104 564 0 563 1 0 1 1 0 8 0 lockfspl 48 264 0 263 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 96 224 0 215 1 0 1 1 0 8 0 zombiepl 144 54521 0 54521 2 1 1 1 0 8 1 processpl 1080 54554 0 54521 3 0 3 3 0 8 0 procpl 672 109988 0 109946 5 1 4 4 0 8 0 sockpl 480 918 0 900 5 2 3 4 0 8 0 mcl64k 65536 2 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 5 0 0 1 0 1 1 0 8 0 mcl9k 9216 2 0 0 1 0 1 1 0 8 0 mcl8k 8192 4 0 0 1 0 1 1 0 8 0 mcl4k 4096 23 0 0 3 1 2 3 0 8 0 mcl2k2 2112 6 0 0 1 0 1 1 0 8 0 mcl2k 2048 517 0 0 54 28 26 54 0 8 0 mtagpl 96 4 0 0 1 0 1 1 0 8 0 mbufpl 256 1023 0 0 27 0 27 27 0 8 0 bufpl 280 57755 0 51436 452 0 452 452 0 8 0 anonpl 24 13283821 0 13256850 204 39 165 189 0 186 1 amapchunkpl 152 1495295 0 1494282 44 3 41 43 0 158 0 amappl16 200 71465 0 70659 56 13 43 55 0 8 0 amappl15 192 63 0 55 1 0 1 1 0 8 0 amappl14 184 3 0 2 1 0 1 1 0 8 0 amappl13 176 27202 0 27198 1 0 1 1 0 8 0 amappl12 168 10 0 8 1 0 1 1 0 8 0 amappl11 160 50 0 37 1 0 1 1 0 8 0 amappl10 152 27190 0 27176 1 0 1 1 0 8 0 amappl9 144 243 0 243 2 2 0 1 0 8 0 amappl8 136 350 0 299 2 0 2 2 0 8 0 amappl7 128 68 0 59 1 0 1 1 0 8 0 amappl6 120 112 0 98 1 0 1 1 0 8 0 amappl5 112 54409 0 54396 1 0 1 1 0 8 0 amappl4 104 537 0 508 1 0 1 1 0 8 0 amappl3 96 27293 0 27281 1 0 1 1 0 8 0 amappl2 88 81827 0 81781 3 1 2 2 0 8 0 amappl1 80 842880 0 842455 14 5 9 12 0 8 0 amappl 88 632907 0 632696 6 0 6 6 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 2 1 0 1 1 0 8 0 uaddrrnd 24 54538 0 54521 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 54538 0 54521 1 0 1 1 0 8 0 vmmpekpl 168 196385 0 196360 2 0 2 2 0 8 0 vmmpepl 168 6076512 0 6074291 148 49 99 120 0 357 2 vmsppl 368 54537 0 54521 2 0 2 2 0 8 0 rwobjpl 56 979136 0 977554 26 3 23 26 0 8 0 pdppl 4096 109083 0 109042 63 22 41 45 0 8 0 pvpl 32 29105260 0 29074963 324 64 260 284 0 265 13 pmappl 232 54537 0 54521 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 372 0 67 10 0 10 10 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(fffffd806e7b0230) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000222cf6e0,fffffd806e7b0230) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e8b3438,ffff8000222cf6e0,ffff80002129b7a8) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002129b7a8,ffff8000222cf998,ffff8000222cf9e0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000222cfa60) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000222cfa60) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2f7949ad080, 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 __mp_lock(ffffffff827d4070) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff827d4070) at __mp_lock+0x129 sys/kern/kern_lock.c:147 uvm_fault(fffffd806e8e3b88,21110665000,0,2) at uvm_fault+0x23a sys/uvm/uvm_fault.c:637 upageflttrap(ffff8000222d5960,21110665000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff8000222d5960) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe6560, count: 7 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 __mp_lock(ffffffff827d4070) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff827d4070) at __mp_lock+0x129 sys/kern/kern_lock.c:147 uvm_fault(fffffd806e8e3b88,21110665000,0,2) at uvm_fault+0x23a sys/uvm/uvm_fault.c:637 upageflttrap(ffff8000222d5960,21110665000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff8000222d5960) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe6560, count: -8