panic: mutex 0xfffffd8063c846e0 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 378018 60478 32767 0x10 0x4000000 0 syz-executor.1 * 35618 3489 32767 0x10 0x4000000 1K syz-executor.0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8246025e) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e8a8850) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256cec00,fffffd806e8a8850) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff57a0,ffff8000256cedf8,ffff8000256cee40) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256ceec0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256ceec0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2912f2c7660, 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 0xfffffd8063c846e0 not held in knote_dequeue ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8246025e) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e8a8850) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256cec00,fffffd806e8a8850) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff57a0,ffff8000256cedf8,ffff8000256cee40) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256ceec0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256ceec0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2912f2c7660, count: -8 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000256ce930 rbx 0xffff800020d59bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81bb3f14 kprintf+0x144 r9 0x1 r10 0x4eb743ce39b08791 r11 0xd01efd890b885997 r12 0xffff800020d599f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81b43698 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000256ce920 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.0) pid=35618 stat=onproc flags process=10 proc=4000000 pri=32, usrpri=80, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff4d20,0xffff8000ffff42b0 process=0xffff8000ffff2618 user=0xffff8000256c9000, vmspace=0xfffffd807f009000 estcpu=36, cpticks=1, pctcpu=0.0 user=0, sys=0, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 60478 414858 96503 32767 3 0x90 nanoslp syz-executor.1 60478 378018 96503 32767 7 0x4000010 syz-executor.1 60478 197655 96503 32767 3 0x4000090 fsleep syz-executor.1 3489 109755 61334 32767 2 0x10 syz-executor.0 * 3489 35618 61334 32767 7 0x4000010 syz-executor.0 3489 397772 61334 32767 3 0x4000090 fsleep syz-executor.0 3489 365109 61334 32767 3 0x4000090 fsleep syz-executor.0 96503 506479 27185 32767 3 0x90 nanoslp syz-executor.1 61334 381858 46514 32767 3 0x90 nanoslp syz-executor.0 27185 385485 66802 0 3 0x82 wait syz-executor.1 46514 433331 66802 0 3 0x82 wait syz-executor.0 66802 41425 48117 0 3 0x82 thrsleep syz-fuzzer 66802 24105 48117 0 3 0x4000082 thrsleep syz-fuzzer 66802 222878 48117 0 3 0x4000082 thrsleep syz-fuzzer 66802 23314 48117 0 3 0x4000082 thrsleep syz-fuzzer 66802 140570 48117 0 3 0x4000082 kqread syz-fuzzer 66802 256911 48117 0 3 0x4000082 thrsleep syz-fuzzer 66802 408772 48117 0 3 0x4000082 thrsleep syz-fuzzer 66802 289872 48117 0 3 0x4000082 thrsleep syz-fuzzer 48117 382500 86374 0 3 0x10008a sigsusp ksh 86374 253233 6022 0 3 0x92 select sshd 272 158269 1 0 3 0x100083 ttyin getty 6022 325653 1 0 3 0x80 select sshd 39938 182968 61789 73 3 0x100090 kqread syslogd 61789 9153 1 0 3 0x100082 netio syslogd 60464 258469 1 77 3 0x100090 poll dhclient 88086 116520 1 0 3 0x80 poll dhclient 58334 523639 0 0 3 0x14200 bored smr 11962 80263 0 0 2 0x14200 zerothread 24494 135439 0 0 3 0x14200 aiodoned aiodoned 95321 114014 0 0 3 0x14200 syncer update 54918 424456 0 0 3 0x14200 cleaner cleaner 70735 409224 0 0 3 0x14200 reaper reaper 73767 170748 0 0 3 0x14200 pgdaemon pagedaemon 52424 27046 0 0 3 0x14200 bored crynlk 97919 146159 0 0 3 0x14200 bored crypto 36235 121150 0 0 3 0x14200 bored viomb 72645 407005 0 0 3 0x40014200 acpi0 acpi0 86399 152655 0 0 3 0x40014200 idle1 36427 468297 0 0 3 0x14200 bored softnet 79751 341598 0 0 3 0x14200 bored systqmp 91274 119445 0 0 3 0x14200 bored systq 21162 388501 0 0 3 0x40014200 bored softclock 57798 353837 0 0 3 0x40014200 idle0 1 367037 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 60478 (syz-executor.1) thread 0xffff8000ffff42a0 (378018) exclusive rwlock amaplk r = 0 (0xfffffd805687b6a0) #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 (0xfffffd807f009d08) #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 3489 (syz-executor.0) thread 0xffff8000ffff57a0 (35618) exclusive kernel_lock &kernel_lock r = 1 (0xffffffff8294f968) #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 10114 6414K 6414K 78643K 11204 0 pcb 13 8K 8K 78643K 13 0 rtable 105 3K 3K 78643K 187 0 ifaddr 39 10K 10K 78643K 39 0 counters 44 34K 34K 78643K 44 0 ioctlops 0 0K 2K 78643K 845 0 iov 0 0K 16K 78643K 4971 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1216 76K 76K 78643K 1222 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 12 0K 1K 78643K 443 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 8 25K 33K 78643K 24453 0 sigio 0 0K 0K 78643K 2 0 proc 48 50K 83K 78643K 364 0 subproc 34 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 317 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 646 66K 68K 78643K 296026 0 UVM aobj 21 2K 2K 78643K 23 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 5 0K 0K 78643K 9 0 temp 101 3985K 4049K 78643K 50734 0 kqueue 6 7K 7K 78643K 1971 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 21 0 19 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 793 0 785 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 479 0 479 1 1 0 1 0 8 0 tcpcb 736 45 0 41 2 1 1 2 0 8 0 arp 120 6 0 0 1 0 1 1 0 8 0 inpcb 304 98 0 92 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 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 sysvmsgpl 40 7 0 2 1 0 1 1 0 8 0 semupl 112 4 0 4 1 1 0 1 0 8 0 semapl 112 439 0 429 1 0 1 1 0 8 0 shmpl 112 20 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 25948 0 24550 88 0 88 88 0 8 0 ffsino 272 25948 0 24550 94 0 94 94 0 8 0 nchpl 144 55181 0 53571 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 111554 0 111554 3 2 1 1 0 8 1 percpumem 16 34 0 0 1 0 1 1 0 8 0 scxspl 216 151809 0 151809 12 11 1 8 0 8 1 plimitpl 152 16 0 7 1 0 1 1 0 8 0 sigapl 424 24640 0 24607 4 0 4 4 0 8 0 futexpl 56 153406 0 153403 1 0 1 1 0 8 0 knotepl 112 40 0 0 2 0 2 2 0 8 0 kqueuepl 216 46763 0 46743 5 3 2 2 0 8 0 pipepl 336 351 0 340 8 6 2 2 0 8 1 fdescpl 496 24624 0 24607 3 0 3 3 0 8 0 filepl 152 82517 0 82411 9 4 5 5 0 8 0 lockfpl 104 31 0 30 1 0 1 1 0 8 0 lockfspl 48 12 0 11 1 0 1 1 0 8 0 sessionpl 144 17 0 7 1 0 1 1 0 8 0 pgrppl 48 21 0 11 1 0 1 1 0 8 0 ucredpl 96 1416 0 1407 1 0 1 1 0 8 0 zombiepl 144 24607 0 24607 3 2 1 1 0 8 1 processpl 1080 24640 0 24607 5 2 3 3 0 8 0 procpl 672 50681 0 50636 4 0 4 4 0 8 0 sockpl 480 963 0 947 4 1 3 4 0 8 0 mcl64k 65536 33 0 0 3 0 3 3 0 8 0 mcl16k 16384 17 0 0 3 0 3 3 0 8 0 mcl12k 12288 17 0 0 2 0 2 2 0 8 0 mcl9k 9216 17 0 0 2 0 2 2 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 25 0 0 3 0 3 3 0 8 0 mcl2k2 2112 10 0 0 1 0 1 1 0 8 0 mcl2k 2048 557 0 0 62 18 44 62 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 822 0 0 33 0 33 33 0 8 0 bufpl 280 27785 0 21468 452 0 452 452 0 8 0 anonpl 24 6204324 0 6112689 613 8 605 607 0 186 0 amapchunkpl 152 683130 0 679214 159 2 157 157 0 158 0 amappl16 200 43185 0 40725 131 1 130 130 0 8 0 amappl15 192 54 0 46 1 0 1 1 0 8 0 amappl14 184 11 0 7 1 0 1 1 0 8 0 amappl13 176 484 0 482 1 0 1 1 0 8 0 amappl12 168 12209 0 12204 1 0 1 1 0 8 0 amappl11 160 35 0 26 1 0 1 1 0 8 0 amappl10 152 12261 0 12251 1 0 1 1 0 8 0 amappl9 144 242 0 240 1 0 1 1 0 8 0 amappl8 136 329 0 272 2 0 2 2 0 8 0 amappl7 128 60 0 52 1 0 1 1 0 8 0 amappl6 120 103 0 86 1 0 1 1 0 8 0 amappl5 112 41830 0 41815 1 0 1 1 0 8 0 amappl4 104 614 0 585 1 0 1 1 0 8 0 amappl3 96 12541 0 12528 1 0 1 1 0 8 0 amappl2 88 28953 0 28908 3 1 2 2 0 8 1 amappl1 80 383889 0 383473 14 5 9 12 0 8 0 amappl 88 287551 0 286978 14 1 13 13 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 22 0 2 1 0 1 1 0 8 0 uaddrrnd 24 24624 0 24607 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 24624 0 24607 1 0 1 1 0 8 0 vmmpekpl 168 109984 0 109959 2 0 2 2 0 8 0 vmmpepl 168 2805249 0 2800902 315 125 190 302 0 357 0 vmsppl 368 24623 0 24607 2 0 2 2 0 8 0 rwobjpl 56 468638 0 465067 57 6 51 52 0 8 0 pdppl 4096 49255 0 49214 63 22 41 45 0 8 0 pvpl 32 15646095 0 15550135 848 17 831 840 0 265 0 pmappl 232 24623 0 24607 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 386 0 51 10 0 10 10 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff82709ff0) 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(ffffffff8294f760) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff8294f760) at __mp_lock+0x129 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb sys/dev/kcov.c:139 uvm_fault(fffffd807f009cf0,6d6141c5000,0,2) at uvm_fault+0x23a sys/uvm/uvm_fault.c:637 upageflttrap(ffff8000256d4cb0,6d6141c5000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff8000256d4cb0) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x6d60e2747b0, count: 4 ddb{0}> trace x86_ipi_db(ffffffff82709ff0) 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(ffffffff8294f760) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff8294f760) at __mp_lock+0x129 sys/kern/kern_lock.c:147 softintr_dispatch(0) at softintr_dispatch+0x4e sys/arch/amd64/amd64/softintr.c:90 Xsoftclock() at Xsoftclock+0x1f __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0xb sys/dev/kcov.c:139 uvm_fault(fffffd807f009cf0,6d6141c5000,0,2) at uvm_fault+0x23a sys/uvm/uvm_fault.c:637 upageflttrap(ffff8000256d4cb0,6d6141c5000) at upageflttrap+0x82 sys/arch/amd64/amd64/trap.c:181 usertrap(ffff8000256d4cb0) at usertrap+0x21a sys/arch/amd64/amd64/trap.c:403 recall_trap() at recall_trap+0x8 end of kernel end trace frame: 0x6d60e2747b0, count: -11 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(ffffffff8246025e) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e8a8850) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256cec00,fffffd806e8a8850) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff57a0,ffff8000256cedf8,ffff8000256cee40) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256ceec0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256ceec0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2912f2c7660, count: 7 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic(ffffffff8246025e) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e8a8850) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256cec00,fffffd806e8a8850) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd8063c846e0,ffff8000256cec00,ffff8000ffff57a0) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff57a0,ffff8000256cedf8,ffff8000256cee40) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256ceec0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256ceec0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x2912f2c7660, count: -8