panic: kernel diagnostic assertion "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519 Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 374416 74252 0 0x12 0x40 0K sshd *102222 78585 0 0x14000 0x200 1 softnet db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162 kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519 taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447 end trace frame: 0x0, count: 10 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 "curproc->p_kd == NULL" failed: file "/syzkaller/managers/multicore/kernel/sys/dev/kcov.c", line 519 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162 kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519 taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447 end trace frame: 0x0, count: -5 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff800020db94a0 rbx 0xffff800020db94b0 rdx 0x8b rcx 0x2 rax 0x1 r8 0xffff800020db9460 r9 0xffffffff8140d116 kprintf+0x146 r10 0x1 r11 0x9d8807188bb17d8b r12 0x3000000008 r13 0xffff800020db9550 r14 0x100 r15 0x1 rip 0xffffffff81f4faf8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020db9490 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (softnet) pid=102222 stat=onproc flags process=14000 proc=200 pri=32, usrpri=50, nice=20 forw=0xffffffffffffffff, list=0xffff800020d984f0,0xffff800020d98c68 process=0xffff800020d9abd0 user=0xffff800020db4000, vmspace=0xffffffff828deaf8 estcpu=0, cpticks=2, pctcpu=0.1 user=0, sys=2, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 30539 139308 62850 0 2 0x2 syz-executor.1 58707 422593 1 0 3 0x100083 ttyin getty 84591 192581 0 0 3 0x14200 acct acct 73856 135794 0 0 3 0x14200 bored sosplice 62850 301227 21109 0 3 0x82 thrsleep syz-fuzzer 62850 440372 21109 0 2 0x4000482 syz-fuzzer 62850 237138 21109 0 3 0x4000082 thrsleep syz-fuzzer 62850 89651 21109 0 2 0x4000482 syz-fuzzer 62850 14559 21109 0 3 0x4000082 thrsleep syz-fuzzer 62850 67083 21109 0 3 0x4000082 thrsleep syz-fuzzer 62850 57960 21109 0 3 0x4000082 thrsleep syz-fuzzer 62850 156545 21109 0 2 0x4000002 syz-fuzzer 62850 404775 21109 0 3 0x4000082 thrsleep syz-fuzzer 21109 395483 74252 0 3 0x10008a pause ksh 74252 374416 42622 0 7 0x52 sshd 42622 20041 1 0 3 0x80 select sshd 38321 507911 40125 74 3 0x100092 bpf pflogd 40125 151826 1 0 3 0x80 netio pflogd 49380 77419 98003 73 3 0x100090 kqread syslogd 98003 129920 1 0 3 0x100082 netio syslogd 85777 65969 1 77 3 0x100090 poll dhclient 45352 463009 1 0 3 0x80 poll dhclient 83347 8955 0 0 3 0x14200 bored smr 90871 289910 0 0 3 0x14200 pgzero zerothread 10562 136675 0 0 3 0x14200 aiodoned aiodoned 71153 247567 0 0 3 0x14200 syncer update 48965 479310 0 0 3 0x14200 cleaner cleaner 61739 52070 0 0 3 0x14200 reaper reaper 96199 466941 0 0 3 0x14200 pgdaemon pagedaemon 90487 286673 0 0 3 0x14200 bored crynlk 77238 393031 0 0 3 0x14200 bored crypto 69426 269485 0 0 3 0x40014200 acpi0 acpi0 347 371264 0 0 3 0x40014200 idle1 *78585 102222 0 0 7 0x14200 softnet 7967 346968 0 0 3 0x14200 bored systqmp 51961 264473 0 0 3 0x14200 bored systq 68081 272363 0 0 3 0x40014200 bored softclock 28254 143909 0 0 3 0x40014200 idle0 1 241409 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff82744e30) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x100 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 kcov_remote_enter+0x62 kr_lookup sys/dev/kcov.c:676 [inline] #3 kcov_remote_enter+0x62 sys/dev/kcov.c:513 #4 taskq_thread+0xd9 sys/kern/kern_task.c:447 #5 proc_trampoline+0x1c Process 30539 (syz-executor.1) thread 0xffff800020eb33d8 (139308) exclusive rrwlock inode r = 0 (0xfffffd806e5bd1a8) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 rw_enter+0x446 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 ufs_ihashins+0x45 sys/ufs/ufs/ufs_ihash.c:140 #4 ffs_vget+0x135 sys/ufs/ffs/ffs_vfsops.c:1350 #5 ffs_inode_alloc+0x1e1 sys/ufs/ffs/ffs_alloc.c:394 #6 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162 #7 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450 #8 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051 #9 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #9 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570 #10 Xsyscall+0x128 exclusive rrwlock inode r = 0 (0xfffffd8066ca82c0) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 rw_enter+0x446 sys/kern/kern_rwlock.c:311 #2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462 #3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:603 #4 vn_lock+0x6c sys/kern/vfs_vnops.c:575 #5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419 #6 namei+0x5f7 sys/kern/vfs_lookup.c:249 #7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3036 #8 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #8 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570 #9 Xsyscall+0x128 Process 74252 (sshd) thread 0xffff8000fffff648 (374416) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82896a28) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 __mp_acquire_count+0x4c sys/kern/kern_lock.c:227 #2 mi_switch+0x390 sys/kern/sched_bsd.c:435 #3 sleep_finish+0x111 sys/kern/kern_synch.c:418 #4 rw_enter+0x3cf #5 solock+0x5a sys/kern/uipc_socket2.c:282 #6 soo_poll+0x3d sys/kern/sys_socket.c:161 #7 selscan+0x14d sys/kern/sys_generic.c:722 #8 dopselect+0x8b7 sys/kern/sys_generic.c:643 #9 sys_select+0x8b sys/kern/sys_generic.c:542 #10 syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] #10 syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570 #11 Xsyscall+0x128 Process 78585 (softnet) thread 0xffff800020d989e0 (102222) shared rwlock softnet r = 0 (0xffff80000002c070) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 taskq_thread+0xcb sys/kern/kern_task.c:445 #2 proc_trampoline+0x1c exclusive mutex /syzkaller/managers/multicore/kernel/sys/dev/kcov.c:92 r = 0 (0xffffffff82744e30) #0 witness_lock+0x4b0 stacktrace_save sys/sys/stacktrace.h:36 [inline] #0 witness_lock+0x4b0 sys/kern/subr_witness.c:1164 #1 mtx_enter_try+0x100 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 kcov_remote_enter+0x62 kr_lookup sys/dev/kcov.c:676 [inline] #3 kcov_remote_enter+0x62 sys/dev/kcov.c:513 #4 taskq_thread+0xd9 sys/kern/kern_task.c:447 #5 proc_trampoline+0x1c ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 9547 6441K 7785K 78643K 21188 0 pcb 13 8K 8K 78643K 503 0 rtable 77 11K 12K 78643K 1346 0 ifaddr 84 16K 17K 78643K 495 0 counters 43 33K 34K 78643K 207 0 ioctlops 0 0K 4K 78643K 1911 0 iov 0 0K 24K 78643K 493 0 mount 1 1K 1K 78643K 1 0 vnodes 1232 77K 78K 78643K 4944 0 UFS quota 1 32K 32K 78643K 1 0 UFS mount 5 36K 36K 78643K 5 0 shm 2 1K 9K 78643K 52 0 VM map 2 1K 1K 78643K 2 0 sem 12 0K 1K 78643K 888 0 dirhash 12 2K 2K 78643K 12 0 ACPI 1824 197K 290K 78643K 13058 0 file desc 4 9K 25K 78643K 9034 0 sigio 0 0K 0K 78643K 34 0 proc 65 63K 95K 78643K 1069 0 subproc 32 2K 2K 78643K 119 0 NFS srvsock 1 0K 0K 78643K 1 0 NFS daemon 1 16K 16K 78643K 1 0 ip_moptions 0 0K 0K 78643K 630 0 in_multi 22 1K 2K 78643K 412 0 ether_multi 1 0K 0K 78643K 71 0 mrt 0 0K 0K 78643K 69 0 ISOFS mount 1 32K 32K 78643K 1 0 MSDOSFS mount 1 16K 16K 78643K 1 0 ttys 73 334K 334K 78643K 73 0 exec 0 0K 2K 78643K 829 0 pfkey data 0 0K 1K 78643K 5 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 250 291K 291K 78643K 21796 0 UVM aobj 69 5K 5K 78643K 82 0 memdesc 1 4K 4K 78643K 1 0 crypto data 1 1K 1K 78643K 1 0 ip6_options 0 0K 0K 78643K 400 0 NDP 16 0K 0K 78643K 124 0 temp 149 3967K 4039K 78643K 50139 0 kqueue 3 4K 18K 78643K 381 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 22 0 18 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 96 313 0 311 1 0 1 1 0 8 0 rtentry 112 153 0 128 2 0 2 2 0 8 0 unpcb 120 2059 0 2003 3 1 2 3 0 8 0 syncache 272 78 0 78 10 10 0 1 0 8 0 tcpqe 32 27 0 27 4 4 0 1 0 8 0 tcpcb 592 1571 0 1567 21 19 2 5 0 8 1 inpcb 296 4484 0 4477 12 10 2 3 0 8 1 rttmr 72 33 0 33 4 3 1 1 0 8 1 nd6 48 32 0 29 1 0 1 1 0 8 0 pkpcb 40 37 0 37 5 5 0 1 0 8 0 kcovpl 48 7 0 5 1 0 1 1 0 8 0 ppxss 1136 43 0 43 6 5 1 1 0 8 1 pffrag 232 27 0 27 3 3 0 1 0 482 0 pffrnode 88 27 0 27 3 3 0 1 0 8 0 pffrent 40 612 0 612 3 3 0 1 0 8 0 pfosfp 40 847 0 423 5 0 5 5 0 8 0 pfosfpen 112 1429 0 714 21 0 21 21 0 8 0 pfrktable 1344 42 0 42 3 3 0 1 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfqueue 264 8 0 8 1 1 0 1 0 8 0 pfstitem 24 49 0 47 1 0 1 1 0 8 0 pfstkey 112 49 0 47 2 1 1 2 0 8 0 pfstate 328 49 0 47 4 3 1 4 0 8 0 pfrule 1360 65 0 64 2 1 1 2 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 419 0 282 12 3 9 12 0 8 0 art_table 32 420 0 282 2 0 2 2 0 8 0 art_node 16 152 0 132 1 0 1 1 0 8 0 sysvmsgpl 40 44 0 21 2 1 1 1 0 8 0 semapl 112 886 0 876 1 0 1 1 0 8 0 shmpl 112 79 0 13 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 13556 0 12136 92 2 90 90 0 8 0 ffsino 272 13556 0 12136 96 0 96 96 0 8 0 nchpl 144 24684 0 23093 60 0 60 60 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 208 5926 0 0 312 0 312 312 0 8 0 namei 1024 61893 0 61892 4 3 1 1 0 8 0 percpumem 16 114 0 82 1 0 1 1 0 8 0 vcpupl 1984 19 0 0 3 0 3 3 0 8 0 vmpool 560 19 0 0 2 0 2 2 0 8 0 pfiaddrpl 120 14 0 14 3 3 0 1 0 8 0 scsiplug 72 9 0 9 2 1 1 1 0 8 1 scxspl 200 73056 0 73056 18 17 1 7 0 8 1 plimitpl 152 409 0 401 1 0 1 1 0 8 0 sigapl 424 9238 0 9206 4 0 4 4 0 8 0 futexpl 56 69241 0 69241 4 3 1 1 0 8 1 knotepl 112 546 0 526 1 0 1 1 0 8 0 kqueuepl 152 4219 0 4216 1 0 1 1 0 8 0 pipepl 304 538 0 527 16 14 2 2 0 8 1 fdescpl 496 9221 0 9206 3 0 3 3 0 8 0 filepl 152 33144 0 33042 7 2 5 6 0 8 1 lockfpl 104 1002 0 1001 1 0 1 1 0 8 0 lockfspl 48 411 0 410 1 0 1 1 0 8 0 sessionpl 120 24 0 13 1 0 1 1 0 8 0 pgrppl 48 42 0 31 1 0 1 1 0 8 0 ucredpl 96 4695 0 4683 1 0 1 1 0 8 0 zombiepl 144 9207 0 9206 2 1 1 1 0 8 0 processpl 1008 9238 0 9206 5 0 5 5 0 8 0 procpl 632 20502 0 20462 13 8 5 5 0 8 1 srpgc 72 2 0 2 1 1 0 1 0 8 0 sosppl 144 117 0 117 8 7 1 1 0 8 1 sockpl 400 6908 0 6839 14 6 8 10 0 8 0 mcl64k 65536 20 0 0 3 0 3 3 0 8 0 mcl16k 16384 10 0 0 2 0 2 2 0 8 0 mcl12k 12288 25 0 0 2 0 2 2 0 8 0 mcl9k 9216 16 0 0 2 0 2 2 0 8 0 mcl8k 8192 20 0 0 3 1 2 3 0 8 0 mcl4k 4096 26 0 0 4 1 3 3 0 8 0 mcl2k2 2112 7 0 0 1 0 1 1 0 8 0 mcl2k 2048 273 0 0 15 0 15 15 0 8 0 mtagpl 96 386 0 0 8 0 8 8 0 8 0 mbufpl 256 981 0 0 58 0 58 58 0 8 0 bufpl 280 17551 0 11295 447 0 447 447 0 8 0 anonpl 16 713507 0 705408 99 64 35 54 0 124 1 amapchunkpl 152 38964 0 38786 46 38 8 19 0 158 0 amappl16 192 31426 0 31096 67 49 18 34 0 8 1 amappl15 184 3 0 1 1 0 1 1 0 8 0 amappl14 176 3754 0 3749 1 0 1 1 0 8 0 amappl13 168 103 0 101 1 0 1 1 0 8 0 amappl12 160 278 0 273 1 0 1 1 0 8 0 amappl11 152 67 0 52 1 0 1 1 0 8 0 amappl10 144 4958 0 4953 1 0 1 1 0 8 0 amappl9 136 317 0 317 1 1 0 1 0 8 0 amappl8 128 410 0 278 5 0 5 5 0 8 0 amappl7 120 5255 0 5246 1 0 1 1 0 8 0 amappl6 112 155 0 133 1 0 1 1 0 8 0 amappl5 104 9442 0 9428 1 0 1 1 0 8 0 amappl4 96 395 0 364 1 0 1 1 0 8 0 amappl3 88 4007 0 3999 1 0 1 1 0 8 0 amappl2 80 64618 0 64542 3 1 2 3 0 8 0 amappl1 72 243217 0 242782 25 15 10 19 0 8 0 amappl 80 20907 0 20836 2 0 2 2 0 84 0 dma4096 4096 1 0 1 1 1 0 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 81 0 13 2 0 2 2 0 8 0 uaddrrnd 24 9240 0 9206 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 9240 0 9206 1 0 1 1 0 8 0 vmmpekpl 168 39945 0 39898 3 0 3 3 0 8 0 vmmpepl 168 1118602 0 1117045 149 69 80 90 0 357 2 vmsppl 368 9239 0 9206 5 1 4 4 0 8 0 pdppl 4096 18487 0 18431 10 2 8 8 0 8 0 pvpl 32 3023594 0 3012586 285 171 114 151 0 265 21 pmappl 232 9239 0 9206 4 1 3 3 0 8 0 extentpl 40 53 0 36 1 0 1 1 0 8 0 phpool 112 336 0 32 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp x86_ipi_db(ffffffff826d7ff0) 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 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc pipe_poll(fffffd806fc0d720,1,ffff8000fffff648) at pipe_poll+0x17c sys/kern/sys_pipe.c:738 selscan(ffff8000fffff648,ffff800020e14810,ffff800020e1481c,c,4,ffff800020e149f0) at selscan+0x14d sys/kern/sys_generic.c:722 dopselect(ffff8000fffff648,c,4317bb3ef20,432490e29e0,0,0) at dopselect+0x8b7 sys/kern/sys_generic.c:643 sys_select(ffff8000fffff648,ffff800020e149a0,ffff800020e149f0) at sys_select+0x8b sys/kern/sys_generic.c:542 syscall(ffff800020e14a70) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020e14a70) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd4ab0, count: 5 ddb{0}> trace x86_ipi_db(ffffffff826d7ff0) 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 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc pipe_poll(fffffd806fc0d720,1,ffff8000fffff648) at pipe_poll+0x17c sys/kern/sys_pipe.c:738 selscan(ffff8000fffff648,ffff800020e14810,ffff800020e1481c,c,4,ffff800020e149f0) at selscan+0x14d sys/kern/sys_generic.c:722 dopselect(ffff8000fffff648,c,4317bb3ef20,432490e29e0,0,0) at dopselect+0x8b7 sys/kern/sys_generic.c:643 sys_select(ffff8000fffff648,ffff800020e149a0,ffff800020e149f0) at sys_select+0x8b sys/kern/sys_generic.c:542 syscall(ffff800020e14a70) at syscall+0x4a1 mi_syscall sys/sys/syscall_mi.h:102 [inline] syscall(ffff800020e14a70) at syscall+0x4a1 sys/arch/amd64/amd64/trap.c:570 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7f7ffffd4ab0, count: -10 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(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162 kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519 taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447 end trace frame: 0x0, count: 10 ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic(ffffffff823bf498) at panic+0x15e sys/kern/subr_prf.c:218 __assert(ffffffff8242d3f9,ffffffff8242c702,207,ffffffff823d1f6e) at __assert+0x2b sys/kern/subr_prf.c:162 kcov_remote_enter(0,ffff800020eb4bd8) at kcov_remote_enter+0x155 sys/dev/kcov.c:519 taskq_thread(ffff80000002c000) at taskq_thread+0xd9 sys/kern/kern_task.c:447 end trace frame: 0x0, count: -5