panic: mutex 0xfffffd806e89e6c0 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 372284 48985 0 0 0 0 syz-executor.1 *234198 22098 0 0 0x4000000 1K 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(fffffd806e7b19a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff80002336d230,fffffd806e7b19a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002120b270,ffff80002336d448,ffff80002336d490) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002336d510) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002336d510) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x1cd883ec440, 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{1}> ddb{1}> set $lines = 0 ddb{1}> set $maxwidth = 0 ddb{1}> show panic *cpu1: mutex 0xfffffd806e89e6c0 not held in knote_dequeue ddb{1}> 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(fffffd806e7b19a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff80002336d230,fffffd806e7b19a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002120b270,ffff80002336d448,ffff80002336d490) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002336d510) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002336d510) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x1cd883ec440, count: -8 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff80002336cf80 rbx 0xffff800020d59bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff816e1c04 kprintf+0x144 r9 0x1 r10 0xd35a0bb6f12e2105 r11 0x12ceae2672726640 r12 0xffff800020d599f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81910f78 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff80002336cf70 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=234198 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=79, nice=20 forw=0xffffffffffffffff, list=0xffff80002120a2b0,0xffff80002120ba60 process=0xffff800022336610 user=0xffff800023368000, vmspace=0xfffffd807f009cf0 estcpu=36, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 48985 372284 23024 0 7 0 syz-executor.1 48985 480438 23024 0 3 0x4000080 fsleep syz-executor.1 22098 368742 23333 0 2 0 syz-executor.0 *22098 234198 23333 0 7 0x4000000 syz-executor.0 23333 491684 47058 0 3 0x82 nanoslp syz-executor.0 26853 67423 0 0 3 0x14280 nfsidl nfsio 78260 59479 0 0 3 0x14280 nfsidl nfsio 77568 92597 0 0 3 0x14280 nfsidl nfsio 97821 231730 0 0 3 0x14280 nfsidl nfsio 26734 188590 0 0 3 0x14280 nfsidl nfsio 69276 207188 0 0 3 0x14280 nfsidl nfsio 26604 216464 0 0 3 0x14280 nfsidl nfsio 50639 129514 0 0 3 0x14280 nfsidl nfsio 97939 173902 0 0 3 0x14280 nfsidl nfsio 86693 231417 0 0 3 0x14280 nfsidl nfsio 52092 410704 0 0 3 0x14280 nfsidl nfsio 42091 451065 0 0 3 0x14280 nfsidl nfsio 68284 68054 0 0 3 0x14280 nfsidl nfsio 42779 186709 0 0 3 0x14280 nfsidl nfsio 90918 203007 0 0 3 0x14280 nfsidl nfsio 83535 33027 0 0 3 0x14280 nfsidl nfsio 69161 401469 0 0 3 0x14280 nfsidl nfsio 89941 463581 0 0 3 0x14280 nfsidl nfsio 80301 504428 0 0 3 0x14280 nfsidl nfsio 38284 417705 0 0 3 0x14280 nfsidl nfsio 89327 30678 0 0 3 0x14200 bored sosplice 23024 204781 47058 0 3 0x82 nanoslp syz-executor.1 47058 14077 43056 0 3 0x82 thrsleep syz-fuzzer 47058 281678 43056 0 3 0x4000082 nanoslp syz-fuzzer 47058 303397 43056 0 3 0x4000082 kqread syz-fuzzer 47058 129100 43056 0 3 0x4000082 thrsleep syz-fuzzer 47058 457415 43056 0 3 0x4000082 thrsleep syz-fuzzer 47058 250212 43056 0 3 0x4000082 thrsleep syz-fuzzer 47058 391097 43056 0 3 0x4000082 thrsleep syz-fuzzer 47058 264979 43056 0 3 0x4000082 thrsleep syz-fuzzer 43056 423980 47698 0 3 0x10008a sigsusp ksh 47698 454197 67689 0 3 0x92 select sshd 42610 148263 1 0 3 0x100083 ttyin getty 67689 223540 1 0 3 0x80 select sshd 33483 404027 81593 74 3 0x100092 bpf pflogd 81593 506431 1 0 3 0x80 netio pflogd 87054 211437 79766 73 3 0x100090 kqread syslogd 79766 485149 1 0 3 0x100082 netio syslogd 52199 205420 1 77 3 0x100090 poll dhclient 35375 425593 1 0 3 0x80 poll dhclient 69955 185795 0 0 3 0x14200 bored smr 42376 158408 0 0 2 0x14200 zerothread 56987 516200 0 0 3 0x14200 aiodoned aiodoned 16660 416447 0 0 3 0x14200 syncer update 89028 331450 0 0 3 0x14200 cleaner cleaner 73389 430148 0 0 3 0x14200 reaper reaper 41940 405014 0 0 3 0x14200 pgdaemon pagedaemon 52073 58979 0 0 3 0x14200 bored crynlk 46571 342071 0 0 3 0x14200 bored crypto 69585 141636 0 0 3 0x14200 bored viomb 97398 176133 0 0 3 0x40014200 acpi0 acpi0 46329 125783 0 0 3 0x40014200 idle1 27885 131605 0 0 3 0x14200 bored softnet 36250 516065 0 0 3 0x14200 bored systqmp 45369 7505 0 0 3 0x14200 bored systq 74194 283083 0 0 3 0x40014200 bored softclock 27396 136868 0 0 3 0x40014200 idle0 1 79852 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 48985 (syz-executor.1) thread 0xffff80002120a2b0 (372284) shared rwlock vmmaplk r = 0 (0xfffffd807f0095d8) #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 22098 (syz-executor.0) thread 0xffff80002120b270 (234198) 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{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10154 6509K 6873K 78643K 12718 0 pcb 13 8K 8K 78643K 147 0 rtable 110 4K 5K 78643K 314 0 ifaddr 64 13K 13K 78643K 106 0 counters 44 34K 34K 78643K 60 0 ioctlops 0 0K 4K 78643K 1548 0 iov 0 0K 12K 78643K 62 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1223 77K 77K 78643K 1756 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 12 0 VM map 2 1K 1K 78643K 2 0 sem 11 1K 1K 78643K 17 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 6 17K 25K 78643K 1897 0 proc 62 63K 95K 78643K 554 0 subproc 32 2K 2K 78643K 55 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 70 0 in_multi 33 2K 2K 78643K 108 0 ether_multi 1 0K 0K 78643K 24 0 mrt 1 0K 0K 78643K 1 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 55 254K 254K 78643K 55 0 exec 0 0K 2K 78643K 386 0 pfkey data 0 0K 0K 78643K 3 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 192 26K 26K 78643K 24145 0 UVM aobj 14 2K 4K 78643K 19 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 93 0 NDP 10 0K 0K 78643K 28 0 temp 107 3984K 4048K 78643K 7838 0 kqueue 7 5K 12K 78643K 116 0 SYN cache 2 16K 16K 78643K 2 0 ddb{1}> 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 46 0 44 1 0 1 1 0 8 0 rtentry 112 60 0 16 2 0 2 2 0 8 0 unpcb 120 471 0 461 1 0 1 1 0 8 0 syncache 296 27 0 27 3 3 0 1 0 8 0 tcpqe 32 171 0 171 4 4 0 1 0 8 0 tcpcb 736 353 0 349 5 4 1 4 0 8 0 arp 120 8 0 2 1 0 1 1 0 8 0 inpcb 304 801 0 795 2 1 1 2 0 8 0 nd6 48 13 0 7 1 0 1 1 0 8 0 pkpcb 40 18 0 18 2 2 0 1 0 8 0 kcovpl 48 3 0 1 1 0 1 1 0 8 0 ppxss 1128 7 0 7 1 1 0 1 0 8 0 pffrag 232 1 0 0 1 0 1 1 0 482 0 pffrnode 88 1 0 0 1 0 1 1 0 8 0 pffrent 40 2 0 1 1 0 1 1 0 8 0 pfosfp 40 1462 0 1015 5 0 5 5 0 8 0 pfosfpen 112 1462 0 714 22 0 22 22 0 8 0 pfrktable 1344 3 0 1 1 0 1 1 0 8 0 pfqueue 264 5 0 5 1 1 0 1 0 8 0 pfstitem 24 31 0 18 1 0 1 1 0 8 0 pfstkey 112 31 0 18 1 0 1 1 0 8 0 pfstate 320 31 0 18 3 1 2 2 0 8 0 pfrule 1360 41 0 26 3 1 2 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 236 0 44 12 0 12 12 0 8 0 art_table 32 237 0 44 2 0 2 2 0 8 0 art_node 16 59 0 19 1 0 1 1 0 8 0 sysvmsgpl 40 24 0 1 1 0 1 1 0 8 0 semupl 112 6 0 6 1 1 0 1 0 8 0 semapl 112 9 0 0 1 0 1 1 0 8 0 shmpl 112 16 0 5 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 3835 0 2424 89 0 89 89 0 8 0 ffsino 272 3835 0 2424 96 1 95 95 0 8 0 nchpl 144 6192 0 4589 61 0 61 61 0 8 0 uvmvnodes 72 4221 0 0 77 0 77 77 0 8 0 vnodes 224 4221 0 0 249 0 249 249 0 8 0 namei 1024 15591 0 15591 1 0 1 1 0 8 1 percpumem 16 42 0 8 1 0 1 1 0 8 0 pfiaddrpl 120 5 0 0 1 0 1 1 0 8 0 scxspl 216 18272 0 18272 9 8 1 8 0 8 1 plimitpl 152 48 0 40 1 0 1 1 0 8 0 sigapl 424 2130 0 2076 7 0 7 7 0 8 0 futexpl 56 12758 0 12757 1 0 1 1 0 8 0 knotepl 112 40 0 0 2 0 2 2 0 8 0 kqueuepl 216 844 0 840 1 0 1 1 0 8 0 pipepl 336 135 0 124 6 5 1 2 0 8 0 fdescpl 496 2093 0 2076 3 0 3 3 0 8 0 filepl 152 7214 0 7111 5 0 5 5 0 8 1 lockfpl 104 188 0 187 1 0 1 1 0 8 0 lockfspl 48 73 0 72 1 0 1 1 0 8 0 sessionpl 144 19 0 8 1 0 1 1 0 8 0 pgrppl 48 19 0 8 1 0 1 1 0 8 0 ucredpl 96 1168 0 1159 1 0 1 1 0 8 0 zombiepl 144 2076 0 2076 1 0 1 1 0 8 1 processpl 1080 2130 0 2076 4 0 4 4 0 8 0 procpl 672 4456 0 4393 6 0 6 6 0 8 0 srpgc 96 2 0 2 1 1 0 1 0 8 0 sosppl 168 5 0 5 1 1 0 1 0 8 0 sockpl 480 1336 0 1318 5 2 3 5 0 8 0 mcl64k 65536 15 0 0 2 0 2 2 0 8 0 mcl16k 16384 3 0 0 1 0 1 1 0 8 0 mcl12k 12288 4 0 0 1 0 1 1 0 8 0 mcl9k 9216 4 0 0 1 0 1 1 0 8 0 mcl8k 8192 5 0 0 1 0 1 1 0 8 0 mcl4k 4096 15 0 0 2 0 2 2 0 8 0 mcl2k 2048 212 0 0 17 0 17 17 0 8 0 mtagpl 96 86 0 0 3 0 3 3 0 8 0 mbufpl 256 528 0 0 27 0 27 27 0 8 0 bufpl 280 5961 0 235 409 0 409 409 0 8 0 anonpl 24 580443 0 572972 108 53 55 90 0 186 0 amapchunkpl 152 57233 0 56817 24 7 17 20 0 158 1 amappl16 200 7086 0 6907 64 54 10 33 0 8 0 amappl15 192 236 0 228 1 0 1 1 0 8 0 amappl14 184 10 0 6 1 0 1 1 0 8 0 amappl13 176 979 0 976 1 0 1 1 0 8 0 amappl12 168 11 0 7 1 0 1 1 0 8 0 amappl11 160 44 0 32 1 0 1 1 0 8 0 amappl10 152 48 0 37 1 0 1 1 0 8 0 amappl9 144 53 0 53 2 2 0 1 0 8 0 amappl8 136 1114 0 1066 2 0 2 2 0 8 0 amappl7 128 809 0 801 1 0 1 1 0 8 0 amappl6 120 119 0 102 1 0 1 1 0 8 0 amappl5 112 1400 0 1388 1 0 1 1 0 8 0 amappl4 104 558 0 527 1 0 1 1 0 8 0 amappl3 96 1100 0 1086 1 0 1 1 0 8 0 amappl2 88 3173 0 3128 2 0 2 2 0 8 0 amappl1 80 36146 0 35712 12 2 10 12 0 8 0 amappl 88 23751 0 23617 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 18 0 5 1 0 1 1 0 8 0 uaddrrnd 24 2093 0 2076 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 2093 0 2076 1 0 1 1 0 8 0 vmmpekpl 168 13436 0 13405 2 0 2 2 0 8 0 vmmpepl 168 235777 0 234246 100 32 68 85 0 357 1 vmsppl 368 2092 0 2076 2 0 2 2 0 8 0 rwobjpl 56 45577 0 44695 22 7 15 19 0 8 0 pdppl 4096 4193 0 4152 57 16 41 45 0 8 0 pvpl 32 1219164 0 1208147 187 81 106 155 0 265 8 pmappl 232 2092 0 2076 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 328 0 29 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff8275cff0) 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(fffffd807f0095c0,ead77749000,0,1) at uvm_fault+0x1a8 sys/uvm/uvm_fault.c:623 upageflttrap(ffff800021289d60,ead77749000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff800021289d60) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe8e80, count: 7 ddb{0}> trace x86_ipi_db(ffffffff8275cff0) 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(fffffd807f0095c0,ead77749000,0,1) at uvm_fault+0x1a8 sys/uvm/uvm_fault.c:623 upageflttrap(ffff800021289d60,ead77749000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff800021289d60) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x7f7ffffe8e80, count: -8 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x18: addq $0x8,%rsp 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(fffffd806e7b19a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff80002336d230,fffffd806e7b19a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002120b270,ffff80002336d448,ffff80002336d490) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002336d510) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002336d510) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x1cd883ec440, count: 7 ddb{1}> 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(fffffd806e7b19a0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff80002336d230,fffffd806e7b19a0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89e6c0,ffff80002336d230,ffff80002120b270) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff80002120b270,ffff80002336d448,ffff80002336d490) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff80002336d510) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff80002336d510) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x1cd883ec440, count: -8