login: panic: kernel diagnostic assertion "TAILQ_EMPTY(&kq->kq_head)" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1268 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 197323 51321 0 0x2 0 0 syz-executor0300 *112919 51321 0 0x2 0x4000000 1K syz-executor0300 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162 kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268 kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286 fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279 closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263 finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691 dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397 syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x553cbc72400, count: 4 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 kernel diagnostic assertion "TAILQ_EMPTY(&kq->kq_head)" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_event.c", line 1268 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162 kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268 kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286 fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279 closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263 finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691 dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397 syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x553cbc72400, count: -11 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff8000212636e0 rbx 0xffff8000212636f0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffffffff821c43c5 kprintf+0x145 r9 0x1 r10 0xcb6961b596649ad8 r11 0x16407f50b9183eb9 r12 0x3000000008 r13 0xffff800021263790 r14 0x100 r15 0x1 rip 0xffffffff81df8258 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff8000212636d0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor0300) pid=112919 stat=onproc flags process=2 proc=4000000 pri=51, usrpri=52, nice=20 forw=0xffffffffffffffff, list=0xffff8000ffff6a90,0xffffffff828cc870 process=0xffff800021237b20 user=0xffff80002125e000, vmspace=0xfffffd806e958b88 estcpu=2, cpticks=2, pctcpu=0.0 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 51321 197323 50703 0 7 0x2 syz-executor0300 51321 190353 50703 0 3 0x4000082 kqread syz-executor0300 *51321 112919 50703 0 7 0x4000002 syz-executor0300 50703 149745 11815 0 3 0x10008a sigsusp ksh 11815 390694 73368 0 3 0x92 select sshd 62372 290428 1 0 3 0x100083 ttyin getty 73368 245579 1 0 3 0x80 select sshd 35433 110868 59713 74 3 0x100092 bpf pflogd 59713 265960 1 0 3 0x80 netio pflogd 54099 272565 9666 73 3 0x100090 kqread syslogd 9666 318417 1 0 3 0x100082 netio syslogd 16601 107028 1 77 3 0x100090 poll dhclient 84410 219328 1 0 3 0x80 poll dhclient 62790 124690 0 0 3 0x14200 bored smr 66871 59757 0 0 3 0x14200 pgzero zerothread 30331 477396 0 0 3 0x14200 aiodoned aiodoned 81708 505581 0 0 3 0x14200 syncer update 95402 453358 0 0 3 0x14200 cleaner cleaner 13988 384572 0 0 3 0x14200 reaper reaper 14947 89188 0 0 3 0x14200 pgdaemon pagedaemon 47789 474653 0 0 3 0x14200 bored crynlk 32799 102920 0 0 3 0x14200 bored crypto 69885 236507 0 0 3 0x14200 bored viomb 13609 335168 0 0 3 0x40014200 acpi0 acpi0 11157 252716 0 0 3 0x40014200 idle1 18238 84317 0 0 3 0x14200 bored softnet 78028 426606 0 0 3 0x14200 bored systqmp 65747 192525 0 0 3 0x14200 bored systq 24956 207493 0 0 3 0x40014200 bored softclock 40753 260519 0 0 3 0x40014200 idle0 1 466301 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks Process 51321 (syz-executor0300) thread 0xffff8000ffff6010 (112919) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff828cca98) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1176 #1 kqueue_close+0x2d sys/kern/kern_event.c:1284 #2 fdrop+0xc2 sys/kern/kern_descrip.c:1279 #3 closef+0x11c sys/kern/kern_descrip.c:1263 #4 finishdup+0x321 sys/kern/kern_descrip.c:691 #5 dodup3+0x5cf sys/kern/kern_descrip.c:397 #6 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #6 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 #7 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9475 6411K 6412K 78643K 10565 0 pcb 13 8K 8K 78643K 13 0 rtable 61 2K 2K 78643K 127 0 ifaddr 29 8K 8K 78643K 30 0 counters 40 33K 33K 78643K 40 0 ioctlops 0 0K 4K 78643K 1467 0 mount 1 1K 1K 78643K 1 0 vnodes 1183 74K 75K 78643K 1188 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 2 0K 0K 78643K 2 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1697 195K 286K 78643K 12598 0 file desc 1 0K 0K 78643K 1 0 proc 59 63K 71K 78643K 367 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 in_multi 11 0K 0K 78643K 11 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 302 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 38 2K 2K 78643K 596 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 4 0K 0K 78643K 4 0 temp 23 3969K 4033K 78643K 1687 0 kqueue 3 4K 4K 78643K 3 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 arp 64 2 0 0 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 120 15 0 13 1 0 1 1 0 8 0 rtentry 112 23 0 1 1 0 1 1 0 8 0 unpcb 120 29 0 19 1 0 1 1 0 8 0 syncache 296 5 0 5 2 1 1 1 0 8 1 tcpqe 32 1 0 1 1 1 0 1 0 8 0 tcpcb 736 8 0 4 1 0 1 1 0 8 0 inpcb 304 29 0 22 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 9 0 2 1 0 1 1 0 8 0 pfstkey 112 9 0 2 1 0 1 1 0 8 0 pfstate 328 9 0 2 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 95 0 0 6 0 6 6 0 8 0 art_table 32 96 0 0 1 0 1 1 0 8 0 art_node 16 22 0 2 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1398 0 16 87 0 87 87 0 8 0 ffsino 272 1398 0 16 93 0 93 93 0 8 0 nchpl 144 1572 0 33 59 1 58 58 0 8 0 uvmvnodes 72 1408 0 0 26 0 26 26 0 8 0 vnodes 224 1408 0 0 83 0 83 83 0 8 0 namei 1024 3781 0 3781 2 1 1 1 0 8 1 percpumem 16 31 0 0 1 0 1 1 0 8 0 scxspl 216 3637 0 3637 10 9 1 8 0 8 1 plimitpl 152 14 0 8 1 0 1 1 0 8 0 sigapl 424 221 0 192 4 0 4 4 0 8 0 knotepl 112 6 0 1 1 0 1 1 0 8 0 kqueuepl 168 2 0 0 1 0 1 1 0 8 0 pipepl 336 64 0 60 2 1 1 1 0 8 0 fdescpl 496 205 0 192 3 0 3 3 0 8 0 filepl 152 959 0 909 2 0 2 2 0 8 0 lockfpl 104 5 0 4 1 0 1 1 0 8 0 lockfspl 48 3 0 2 1 0 1 1 0 8 0 sessionpl 144 18 0 9 1 0 1 1 0 8 0 pgrppl 48 18 0 9 1 0 1 1 0 8 0 ucredpl 96 62 0 53 1 0 1 1 0 8 0 zombiepl 144 192 0 192 2 1 1 1 0 8 1 processpl 1080 221 0 192 3 0 3 3 0 8 0 procpl 672 223 0 192 3 0 3 3 0 8 0 sockpl 432 73 0 54 4 1 3 3 0 8 0 mcl4k 4096 3 0 0 1 0 1 1 0 8 0 mcl2k 2048 64 0 0 8 0 8 8 0 8 0 mtagpl 96 1 0 0 1 0 1 1 0 8 0 mbufpl 256 95 0 0 5 0 5 5 0 8 0 bufpl 280 2005 0 112 136 0 136 136 0 8 0 anonpl 24 19974 0 18705 11 2 9 10 0 186 1 amapchunkpl 152 531 0 490 3 1 2 3 0 158 0 amappl16 200 77 0 72 1 0 1 1 0 8 0 amappl15 192 1 0 0 1 0 1 1 0 8 0 amappl14 184 22 0 19 1 0 1 1 0 8 0 amappl13 176 14 0 13 2 1 1 1 0 8 0 amappl12 168 4 0 4 2 1 1 1 0 8 1 amappl11 160 51 0 36 1 0 1 1 0 8 0 amappl10 152 12 0 10 1 0 1 1 0 8 0 amappl9 144 234 0 234 2 1 1 1 0 8 1 amappl8 136 63 0 61 1 0 1 1 0 8 0 amappl7 128 209 0 208 1 0 1 1 0 8 0 amappl6 120 57 0 49 1 0 1 1 0 8 0 amappl5 112 355 0 340 1 0 1 1 0 8 0 amappl4 104 275 0 252 1 0 1 1 0 8 0 amappl3 96 108 0 100 1 0 1 1 0 8 0 amappl2 88 840 0 779 2 0 2 2 0 8 0 amappl1 80 14214 0 13776 17 6 11 17 0 8 0 amappl 88 405 0 383 1 0 1 1 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 24 205 0 192 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 205 0 192 1 0 1 1 0 8 0 vmmpekpl 168 5587 0 5569 1 0 1 1 0 8 0 vmmpepl 168 30085 0 29205 51 12 39 48 0 357 0 vmsppl 368 204 0 192 2 0 2 2 0 8 0 rwobjpl 56 7705 0 7129 14 5 9 13 0 8 0 pdppl 4096 417 0 384 51 18 33 39 0 8 0 pvpl 32 80770 0 77718 34 6 28 28 0 265 0 pmappl 232 204 0 192 1 0 1 1 0 8 0 extentpl 40 58 0 40 1 0 1 1 0 8 0 phpool 112 267 0 23 8 0 8 8 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff82738ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352 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(ffffffff828cc890) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cc890) 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 end of kernel end trace frame: 0x7f7fffff4f40, count: 9 ddb{0}> trace x86_ipi_db(ffffffff82738ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352 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(ffffffff828cc890) at __mp_lock+0x129 __mp_lock_spin sys/kern/kern_lock.c:116 [inline] __mp_lock(ffffffff828cc890) 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 end of kernel end trace frame: 0x7f7fffff4f40, 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:398 panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162 kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268 kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286 fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279 closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263 finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691 dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397 syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x553cbc72400, count: 4 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823c3c11) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d86c,ffffffff82425328,4f4,ffffffff823ad335) at __assert+0x2b sys/kern/subr_prf.c:162 kqueue_terminate(0,fffffd806e92ebd0) at kqueue_terminate+0x152 sys/kern/kern_event.c:1268 kqueue_close(fffffd807bacfa18,ffff8000ffff6010) at kqueue_close+0x40 sys/kern/kern_event.c:1286 fdrop(fffffd807bacfa18,ffff8000ffff6010) at fdrop+0xc2 sys/kern/kern_descrip.c:1279 closef(fffffd807bacfa18,ffff8000ffff6010) at closef+0x11c sys/kern/kern_descrip.c:1263 finishdup(ffff8000ffff6010,fffffd807bacf1c8,4,3,ffff800021263ac0,2) at finishdup+0x321 sys/kern/kern_descrip.c:691 dodup3(ffff8000ffff6010,4,3,0,ffff800021263ac0) at dodup3+0x5cf sys/kern/kern_descrip.c:397 syscall(ffff800021263b40) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800021263b40) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:590 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x553cbc72400, count: -11 ddb{1}>