panic: mutex 0xfffffd806e89b360 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 353054 50403 0 0 0 0 syz-executor.0 * 7101 50403 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(fffffd806e7ac4d0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000234c78b0,fffffd806e7ac4d0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000212727e0,ffff8000234c7b68,ffff8000234c7bb0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000234c7c30) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c7c30) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8bdd1d52260, 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 0xfffffd806e89b360 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(fffffd806e7ac4d0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000234c78b0,fffffd806e7ac4d0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000212727e0,ffff8000234c7b68,ffff8000234c7bb0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000234c7c30) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c7c30) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8bdd1d52260, count: -8 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000234c76a0 rbx 0xffff800020d59bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff816e1c04 kprintf+0x144 r9 0x1 r10 0xf8f7378ca7c81999 r11 0x295b1f041a184951 r12 0xffff800020d599f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81910f78 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000234c7690 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=7101 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff8000212722a0,0xffffffff827da780 process=0xffff8000212261d0 user=0xffff8000234c2000, vmspace=0xfffffd807f009730 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 50403 353054 1705 0 7 0 syz-executor.0 50403 498427 1705 0 3 0x4000080 fsleep syz-executor.0 *50403 7101 1705 0 7 0x4000000 syz-executor.0 608 152800 50357 0 3 0x2 biowait syz-executor.1 1705 330162 50357 0 3 0x82 nanoslp syz-executor.0 50357 164038 90262 0 3 0x82 thrsleep syz-fuzzer 50357 492938 90262 0 3 0x4000082 nanoslp syz-fuzzer 50357 78800 90262 0 3 0x4000082 thrsleep syz-fuzzer 50357 125602 90262 0 3 0x4000082 thrsleep syz-fuzzer 50357 159594 90262 0 3 0x4000082 thrsleep syz-fuzzer 50357 209425 90262 0 3 0x4000082 kqread syz-fuzzer 50357 520026 90262 0 3 0x4000082 thrsleep syz-fuzzer 50357 239908 90262 0 3 0x4000082 nanoslp syz-fuzzer 90262 68465 46636 0 3 0x10008a sigsusp ksh 46636 333569 11818 0 3 0x92 select sshd 37817 216323 1 0 3 0x100083 ttyin getty 11818 334150 1 0 3 0x80 select sshd 7267 121706 25696 74 3 0x100092 bpf pflogd 25696 316309 1 0 3 0x80 netio pflogd 44903 287334 79469 73 3 0x100090 kqread syslogd 79469 259066 1 0 3 0x100082 netio syslogd 53255 161424 1 77 3 0x100090 poll dhclient 39524 391117 1 0 3 0x80 poll dhclient 64483 381817 0 0 3 0x14200 bored smr 90311 176567 0 0 2 0x14200 zerothread 56524 378343 0 0 3 0x14200 aiodoned aiodoned 98301 365453 0 0 3 0x14200 syncer update 78721 443438 0 0 3 0x14200 cleaner cleaner 91865 377233 0 0 3 0x14200 reaper reaper 90834 342323 0 0 3 0x14200 pgdaemon pagedaemon 59054 395676 0 0 3 0x14200 bored crynlk 71256 376773 0 0 3 0x14200 bored crypto 24849 160880 0 0 3 0x14200 bored viomb 77306 49000 0 0 3 0x40014200 acpi0 acpi0 71369 173028 0 0 3 0x40014200 idle1 72824 60096 0 0 3 0x14200 bored softnet 71232 474867 0 0 3 0x14200 bored systqmp 57636 66160 0 0 3 0x14200 bored systq 14089 1294 0 0 3 0x40014200 bored softclock 83641 518770 0 0 3 0x40014200 idle0 1 61130 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 50403 (syz-executor.0) thread 0xffff8000212727e0 (7101) 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 Process 608 (syz-executor.1) thread 0xffff800021272fc0 (152800) exclusive rrwlock inode r = 0 (0xfffffd806aaea3c8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 rw_enter+0x3ee sys/kern/kern_rwlock.c:310 #2 rrw_enter+0x8b sys/kern/kern_rwlock.c:461 #3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:614 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:579 #5 vget+0x1f7 sys/kern/vfs_subr.c:676 #6 ufs_ihashget+0x121 sys/ufs/ufs/ufs_ihash.c:119 #7 ffs_vget+0x7c sys/ufs/ffs/ffs_vfsops.c:1321 #8 ufs_lookup+0x1471 sys/ufs/ufs/ufs_lookup.c:487 #9 VOP_LOOKUP+0x5b sys/kern/vfs_vops.c:88 #10 vfs_lookup+0x74a sys/kern/vfs_lookup.c:562 #11 namei+0x58a sys/kern/vfs_lookup.c:245 #12 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1859 #13 syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] #13 syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 #14 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd806aaea5e8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1182 #1 rw_enter+0x3ee sys/kern/kern_rwlock.c:310 #2 rrw_enter+0x8b sys/kern/kern_rwlock.c:461 #3 VOP_LOCK+0x87 sys/kern/vfs_vops.c:614 #4 vn_lock+0x84 sys/kern/vfs_vnops.c:579 #5 vfs_lookup+0xec sys/kern/vfs_lookup.c:413 #6 namei+0x58a sys/kern/vfs_lookup.c:245 #7 dounlinkat+0x99 sys/kern/vfs_syscalls.c:1859 #8 syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 #9 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10122 6512K 6936K 78643K 22434 0 pcb 13 8K 8K 78643K 491 0 rtable 105 3K 3K 78643K 195 0 ifaddr 44 10K 10K 78643K 45 0 sysctl 2 0K 0K 78643K 2 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 4K 78643K 3712 0 iov 0 0K 12K 78643K 2329 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1221 77K 77K 78643K 5504 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 5K 78643K 382 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 227 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 5 13K 25K 78643K 44135 0 proc 60 63K 95K 78643K 438 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 19 95K 95K 78643K 19 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 208 26K 26K 78643K 531733 0 UVM aobj 131 4K 4K 78643K 131 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 6 0K 0K 78643K 10 0 temp 106 3985K 4049K 78643K 95557 0 kqueue 6 5K 10K 78643K 1630 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 19 0 17 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 8244 0 8234 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpcb 736 2065 0 2059 11 10 1 6 0 8 0 arp 120 6 0 0 1 0 1 1 0 8 0 inpcb 304 5261 0 5255 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 pffrag 232 6 0 6 1 1 0 1 0 482 0 pffrnode 88 4 0 4 1 1 0 1 0 8 0 pffrent 40 141 0 141 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 19 0 17 1 0 1 1 0 8 0 pfstkey 112 19 0 17 1 0 1 1 0 8 0 pfstate 320 19 0 17 2 1 1 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 256 187 0 0 12 0 12 12 0 8 0 art_table 32 188 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 semapl 112 225 0 215 1 0 1 1 0 8 0 shmpl 112 128 0 0 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 46479 0 45075 89 1 88 89 0 8 0 ffsino 272 46479 0 45075 94 0 94 94 0 8 0 nchpl 144 111436 0 109821 123 62 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 232805 0 232805 1 0 1 1 0 8 1 percpumem 16 34 0 0 1 0 1 1 0 8 0 scxspl 216 273241 0 273240 9 8 1 8 0 8 0 plimitpl 152 1258 0 1250 1 0 1 1 0 8 0 sigapl 424 44350 0 44318 4 0 4 4 0 8 0 futexpl 56 205258 0 205257 3 2 1 1 0 8 0 knotepl 112 46 0 0 2 0 2 2 0 8 0 kqueuepl 216 4826 0 4821 1 0 1 1 0 8 0 pipepl 336 76 0 65 1 0 1 1 0 8 0 fdescpl 496 44334 0 44318 3 0 3 3 0 8 0 filepl 152 108538 0 108435 70 65 5 5 0 8 0 lockfpl 104 2102 0 2101 1 0 1 1 0 8 0 lockfspl 48 886 0 885 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 96 107 0 98 1 0 1 1 0 8 0 zombiepl 144 44318 0 44318 1 0 1 1 0 8 1 processpl 1080 44350 0 44318 3 0 3 3 0 8 0 procpl 672 99433 0 99392 7 3 4 5 0 8 0 sockpl 480 13524 0 13506 19 16 3 4 0 8 0 mcl64k 65536 13 0 0 2 0 2 2 0 8 0 mcl16k 16384 19 0 0 3 1 2 3 0 8 0 mcl12k 12288 49 0 0 3 1 2 2 0 8 0 mcl9k 9216 57 0 0 2 0 2 2 0 8 0 mcl8k 8192 19 0 0 3 0 3 3 0 8 0 mcl4k 4096 41 0 0 4 1 3 3 0 8 0 mcl2k2 2112 17 0 0 2 0 2 2 0 8 0 mcl2k 2048 211 0 0 12 2 10 12 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 1740 0 0 17 6 11 14 0 8 0 bufpl 280 47615 0 41296 452 0 452 452 0 8 0 anonpl 24 11284624 0 11277846 96 29 67 67 0 186 22 amapchunkpl 152 1258545 0 1258173 51 34 17 17 0 158 2 amappl16 200 84569 0 84385 25 7 18 23 0 8 8 amappl15 192 60 0 54 1 0 1 1 0 8 0 amappl14 184 22085 0 22080 1 0 1 1 0 8 0 amappl13 176 22064 0 22062 1 0 1 1 0 8 0 amappl12 168 10 0 8 1 0 1 1 0 8 0 amappl11 160 43 0 30 1 0 1 1 0 8 0 amappl10 152 43 0 33 1 0 1 1 0 8 0 amappl9 144 230 0 230 3 3 0 1 0 8 0 amappl8 136 611 0 527 4 1 3 3 0 8 0 amappl7 128 65 0 56 1 0 1 1 0 8 0 amappl6 120 113 0 97 1 0 1 1 0 8 0 amappl5 112 201 0 190 1 0 1 1 0 8 0 amappl4 104 22637 0 22606 2 1 1 2 0 8 0 amappl3 96 23905 0 23892 1 0 1 1 0 8 0 amappl2 88 68362 0 68318 3 1 2 3 0 8 0 amappl1 80 704474 0 704053 12 2 10 12 0 8 0 amappl 88 530453 0 530336 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 64 130 0 0 3 0 3 3 0 8 0 uaddrrnd 24 44334 0 44318 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 44334 0 44318 1 0 1 1 0 8 0 vmmpekpl 168 203442 0 203416 2 0 2 2 0 8 0 vmmpepl 168 4904840 0 4903366 129 49 80 80 0 357 10 vmsppl 368 44333 0 44318 2 0 2 2 0 8 0 rwobjpl 56 821354 0 820446 28 11 17 17 0 8 4 pdppl 4096 88675 0 88636 57 16 41 45 0 8 2 pvpl 32 19206361 0 19196333 401 282 119 132 0 265 34 pmappl 232 44333 0 44318 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 317 0 40 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+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff827d4070) at __mp_lock+0x122 sys/kern/kern_lock.c:147 intr_handler(ffff8000234b9cc0,ffff80000006a400) at intr_handler+0x5e sys/arch/amd64/amd64/intr.c:532 Xintr_ioapic_edge17_untramp() at Xintr_ioapic_edge17_untramp+0x18f end of kernel end trace frame: 0x7f7ffffcf8b0, count: 9 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+0x122 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff827d4070) at __mp_lock+0x122 sys/kern/kern_lock.c:147 intr_handler(ffff8000234b9cc0,ffff80000006a400) at intr_handler+0x5e sys/arch/amd64/amd64/intr.c:532 Xintr_ioapic_edge17_untramp() at Xintr_ioapic_edge17_untramp+0x18f end of kernel end trace frame: 0x7f7ffffcf8b0, count: -6 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(fffffd806e7ac4d0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000234c78b0,fffffd806e7ac4d0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000212727e0,ffff8000234c7b68,ffff8000234c7bb0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000234c7c30) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c7c30) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8bdd1d52260, 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(fffffd806e7ac4d0) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000234c78b0,fffffd806e7ac4d0) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e89b360,ffff8000234c78b0,ffff8000212727e0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000212727e0,ffff8000234c7b68,ffff8000234c7bb0) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000234c7c30) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234c7c30) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x8bdd1d52260, count: -8 ddb{1}>