login: panic: mutex 0xfffffd806e9a9af8 not held in knote_dequeue Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 34680 5803 32767 0x10 0 1 syz-executor.0 *458157 83428 32767 0x10 0x4000000 0K syz-executor.1 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(fffffd806e8aba10) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256dca20,fffffd806e8aba10) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff4008,ffff8000256dcc18,ffff8000256dcc60) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256dcce0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256dcce0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf6b426c8510, 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 0xfffffd806e9a9af8 not held in knote_dequeue ddb{0}> 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(fffffd806e8aba10) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256dca20,fffffd806e8aba10) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff4008,ffff8000256dcc18,ffff8000256dcc60) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256dcce0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256dcce0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf6b426c8510, count: -8 ddb{0}> show registers rdi 0 rsi 0x1 rbp 0xffff8000256dc750 rbx 0xffffffff8270abf7 cpu_info_full_primary+0x2bf7 rdx 0x8b rcx 0x2 rax 0x3a r8 0xffffffff81bb3f14 kprintf+0x144 r9 0x1 r10 0xeacd373712c12ef9 r11 0x17593754a5df369 r12 0xffffffff8270a9f8 cpu_info_full_primary+0x29f8 r13 0 r14 0 r15 0x1 rip 0xffffffff81b43698 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000256dc740 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor.1) pid=458157 stat=onproc flags process=10 proc=4000000 pri=81, usrpri=81, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff5a48,0xffffffff828f5570 process=0xffff8000ffff1970 user=0xffff8000256d7000, vmspace=0xfffffd807f009b80 estcpu=31, cpticks=0, pctcpu=0.0 user=0, sys=0, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 5803 34680 27510 32767 7 0x10 syz-executor.0 5803 519689 27510 32767 2 0x4000010 syz-executor.0 83428 49125 28998 32767 2 0x10 syz-executor.1 83428 364070 28998 32767 3 0x4000090 fsleep syz-executor.1 83428 475620 28998 32767 3 0x4000090 fsleep syz-executor.1 *83428 458157 28998 32767 7 0x4000010 syz-executor.1 28998 381643 30669 32767 3 0x90 nanoslp syz-executor.1 30669 300186 81489 0 3 0x82 wait syz-executor.1 27510 300233 8496 32767 3 0x90 nanoslp syz-executor.0 8496 389143 81489 0 3 0x82 wait syz-executor.0 81489 432985 89218 0 3 0x82 thrsleep syz-fuzzer 81489 480712 89218 0 3 0x4000082 nanoslp syz-fuzzer 81489 292017 89218 0 3 0x4000082 thrsleep syz-fuzzer 81489 66401 89218 0 3 0x4000082 kqread syz-fuzzer 81489 253698 89218 0 3 0x4000082 thrsleep syz-fuzzer 81489 324773 89218 0 3 0x4000082 thrsleep syz-fuzzer 81489 251706 89218 0 3 0x4000082 thrsleep syz-fuzzer 81489 184710 89218 0 3 0x4000082 thrsleep syz-fuzzer 89218 448639 19442 0 3 0x10008a sigsusp ksh 19442 132209 15290 0 3 0x92 select sshd 38507 264030 1 0 3 0x100083 ttyin getty 15290 146760 1 0 3 0x80 select sshd 93465 144664 60272 73 3 0x100090 kqread syslogd 60272 267047 1 0 3 0x100082 netio syslogd 57787 210581 1 77 3 0x100090 poll dhclient 79199 226633 1 0 3 0x80 poll dhclient 75237 178166 0 0 3 0x14200 bored smr 27124 460148 0 0 2 0x14200 zerothread 1358 170976 0 0 3 0x14200 aiodoned aiodoned 5468 514220 0 0 3 0x14200 syncer update 53482 374666 0 0 3 0x14200 cleaner cleaner 54157 372737 0 0 3 0x14200 reaper reaper 47828 364879 0 0 3 0x14200 pgdaemon pagedaemon 42174 412945 0 0 3 0x14200 bored crynlk 98836 230375 0 0 3 0x14200 bored crypto 23665 365707 0 0 3 0x14200 bored viomb 96025 63833 0 0 3 0x40014200 acpi0 acpi0 3082 482958 0 0 3 0x40014200 idle1 72552 271630 0 0 3 0x14200 bored softnet 65613 33917 0 0 3 0x14200 bored systqmp 68554 332333 0 0 3 0x14200 bored systq 69145 489802 0 0 3 0x40014200 bored softclock 51097 383082 0 0 3 0x40014200 idle0 1 272319 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks Process 83428 (syz-executor.1) thread 0xffff8000ffff4008 (458157) 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{0}> 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 15 0 iov 0 0K 0K 78643K 6 0 mount 1 1K 1K 78643K 1 0 log 0 0K 0K 78643K 1 0 vnodes 1216 76K 76K 78643K 1221 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 1K 78643K 2 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 0K 78643K 105 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 8 25K 33K 78643K 736 0 sigio 0 0K 0K 78643K 15 0 proc 48 50K 70K 78643K 355 0 subproc 34 2K 2K 78643K 34 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 8 0 in_multi 33 2K 2K 78643K 35 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 319 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 649 64K 64K 78643K 10750 0 UVM aobj 3 2K 2K 78643K 3 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 NDP 5 0K 0K 78643K 9 0 temp 75 3979K 4043K 78643K 3234 0 kqueue 5 5K 9K 78643K 15 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 19 0 17 1 0 1 1 0 8 0 rtentry 112 45 0 1 2 0 2 2 0 8 0 unpcb 120 52 0 44 1 0 1 1 0 8 0 syncache 296 4 0 4 1 1 0 1 0 8 0 tcpqe 32 349 0 349 2 2 0 1 0 8 0 tcpcb 736 16 0 12 1 0 1 1 0 8 0 arp 120 6 0 0 1 0 1 1 0 8 0 inpcb 304 238 0 232 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 256 188 0 0 12 0 12 12 0 8 0 art_table 32 189 0 0 2 0 2 2 0 8 0 art_node 16 44 0 4 1 0 1 1 0 8 0 sysvmsgpl 40 11 0 4 1 0 1 1 0 8 0 semupl 112 7 0 7 1 1 0 1 0 8 0 semapl 112 100 0 90 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 2118 0 720 88 0 88 88 0 8 0 ffsino 272 2118 0 720 94 0 94 94 0 8 0 nchpl 144 3068 0 1459 60 0 60 60 0 8 0 uvmvnodes 72 2161 0 0 40 0 40 40 0 8 0 vnodes 224 2161 0 0 128 0 128 128 0 8 0 namei 1024 7183 0 7183 2 1 1 1 0 8 1 percpumem 16 34 0 0 1 0 1 1 0 8 0 scxspl 216 9048 0 9048 11 10 1 8 0 8 1 plimitpl 152 16 0 7 1 0 1 1 0 8 0 sigapl 424 923 0 890 4 0 4 4 0 8 0 futexpl 56 6216 0 6214 1 0 1 1 0 8 0 knotepl 112 32 0 0 1 0 1 1 0 8 0 kqueuepl 216 1957 0 1951 1 0 1 1 0 8 0 pipepl 336 77 0 66 5 4 1 2 0 8 0 fdescpl 496 907 0 890 3 0 3 3 0 8 0 filepl 152 4242 0 4140 14 9 5 5 0 8 1 lockfpl 104 13 0 12 1 0 1 1 0 8 0 lockfspl 48 5 0 4 1 0 1 1 0 8 0 sessionpl 144 17 0 7 1 0 1 1 0 8 0 pgrppl 48 18 0 8 1 0 1 1 0 8 0 ucredpl 96 81 0 72 1 0 1 1 0 8 0 zombiepl 144 890 0 890 2 1 1 1 0 8 1 processpl 1080 923 0 890 5 2 3 3 0 8 0 procpl 672 1782 0 1738 5 1 4 4 0 8 0 sockpl 480 485 0 469 3 0 3 3 0 8 0 mcl64k 65536 2 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 7 0 0 1 0 1 1 0 8 0 mcl4k 4096 12 0 0 2 0 2 2 0 8 0 mcl2k2 2112 1 0 0 1 0 1 1 0 8 0 mcl2k 2048 320 0 0 31 7 24 31 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 401 0 0 17 0 17 17 0 8 0 bufpl 280 4054 0 144 280 0 280 280 0 8 0 anonpl 24 595707 0 492392 697 54 643 654 0 186 20 amapchunkpl 152 28727 0 24617 167 8 159 161 0 158 0 amappl16 200 19462 0 16894 293 157 136 148 0 8 0 amappl15 192 57 0 47 1 0 1 1 0 8 0 amappl14 184 358 0 353 2 1 1 1 0 8 0 amappl13 176 46 0 43 1 0 1 1 0 8 0 amappl12 168 14 0 11 1 0 1 1 0 8 0 amappl11 160 35 0 26 1 0 1 1 0 8 0 amappl10 152 45 0 35 1 0 1 1 0 8 0 amappl9 144 595 0 591 1 0 1 1 0 8 0 amappl8 136 303 0 264 2 0 2 2 0 8 0 amappl7 128 60 0 52 1 0 1 1 0 8 0 amappl6 120 454 0 438 1 0 1 1 0 8 0 amappl5 112 475 0 466 1 0 1 1 0 8 0 amappl4 104 822 0 787 1 0 1 1 0 8 0 amappl3 96 93 0 84 1 0 1 1 0 8 0 amappl2 88 1029 0 984 3 1 2 2 0 8 0 amappl1 80 17484 0 17070 13 3 10 12 0 8 0 amappl 88 10188 0 9597 14 0 14 14 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 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 907 0 890 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 907 0 890 1 0 1 1 0 8 0 vmmpekpl 168 9022 0 9004 1 0 1 1 0 8 0 vmmpepl 168 124224 0 119784 312 114 198 286 0 357 4 vmsppl 368 906 0 890 2 0 2 2 0 8 0 rwobjpl 56 37773 0 34098 77 25 52 56 0 8 0 pdppl 4096 1821 0 1780 63 22 41 45 0 8 0 pvpl 32 992188 0 884530 973 76 897 910 0 265 28 pmappl 232 906 0 890 2 1 1 2 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 326 0 36 9 0 9 9 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(ffffffff8246025e) at panic+0x177 sys/kern/subr_prf.c:202 knote_dequeue(fffffd806e8aba10) at knote_dequeue+0x12b sys/kern/kern_event.c:1860 filt_timermodify(ffff8000256dca20,fffffd806e8aba10) at filt_timermodify+0x6f sys/kern/kern_event.c:479 kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 filter_modify sys/kern/kern_event.c:662 [inline] kqueue_register(fffffd806e9a9af8,ffff8000256dca20,ffff8000ffff4008) at kqueue_register+0xa89 sys/kern/kern_event.c:1125 sys_kevent(ffff8000ffff4008,ffff8000256dcc18,ffff8000256dcc60) at sys_kevent+0x214 sys/kern/kern_event.c:887 syscall(ffff8000256dcce0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000256dcce0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf6b426c8510, 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 pvclock_get_timecount(ffffffff82701478) at pvclock_get_timecount+0x67 rdtsc machine/cpufunc.h:302 [inline] pvclock_get_timecount(ffffffff82701478) at pvclock_get_timecount+0x67 sys/dev/pv/pvclock.c:234 nanouptime(ffff8000234afe78) at nanouptime+0x69 tc_delta sys/kern/kern_tc.c:139 [inline] nanouptime(ffff8000234afe78) at nanouptime+0x69 binuptime sys/kern/kern_tc.c:193 [inline] nanouptime(ffff8000234afe78) at nanouptime+0x69 sys/kern/kern_tc.c:203 clock_gettime(ffff8000ffff47e8,3,ffff8000234afe78) at clock_gettime+0x88 sys/kern/kern_time.c:123 sys_clock_gettime(ffff8000ffff47e8,ffff8000234afee0,ffff8000234aff30) at sys_clock_gettime+0x4c sys/kern/kern_time.c:165 syscall(ffff8000234affb0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234affb0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc2970, count: 6 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 pvclock_get_timecount(ffffffff82701478) at pvclock_get_timecount+0x67 rdtsc machine/cpufunc.h:302 [inline] pvclock_get_timecount(ffffffff82701478) at pvclock_get_timecount+0x67 sys/dev/pv/pvclock.c:234 nanouptime(ffff8000234afe78) at nanouptime+0x69 tc_delta sys/kern/kern_tc.c:139 [inline] nanouptime(ffff8000234afe78) at nanouptime+0x69 binuptime sys/kern/kern_tc.c:193 [inline] nanouptime(ffff8000234afe78) at nanouptime+0x69 sys/kern/kern_tc.c:203 clock_gettime(ffff8000ffff47e8,3,ffff8000234afe78) at clock_gettime+0x88 sys/kern/kern_time.c:123 sys_clock_gettime(ffff8000ffff47e8,ffff8000234afee0,ffff8000234aff30) at sys_clock_gettime+0x4c sys/kern/kern_time.c:165 syscall(ffff8000234affb0) at syscall+0x5bf mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff8000234affb0) at syscall+0x5bf sys/arch/amd64/amd64/trap.c:587 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffc2970, count: -9