panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 951 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 472970 21293 0 0x2 0x1 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff8336edd9) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833afff6,ffffffff833c2f1e,3b7,ffffffff833ed01e) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002a3cf508,ffffffff8336a3ec) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952 pppx_if_destroy(205b9a,ffff80002a3cf500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,83,2000,ffff80002a2e5508) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80002a35bb00) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805a4db2c8,83,fffffd80097fb208,ffff80002a2e5508) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805c9a0960,ffff80002a2e5508) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805c9a0960,ffff80002a2e5508) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80002a2e5508) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80002a2e5508,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80002a2e5508,ffff80002a35be70,ffff80002a35bdc0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 end trace frame: 0xffff80002a35be60, count: 0 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: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 951 ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff8336edd9) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833afff6,ffffffff833c2f1e,3b7,ffffffff833ed01e) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002a3cf508,ffffffff8336a3ec) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952 pppx_if_destroy(205b9a,ffff80002a3cf500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,83,2000,ffff80002a2e5508) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80002a35bb00) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805a4db2c8,83,fffffd80097fb208,ffff80002a2e5508) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805c9a0960,ffff80002a2e5508) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805c9a0960,ffff80002a2e5508) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80002a2e5508) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80002a2e5508,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80002a2e5508,ffff80002a35be70,ffff80002a35bdc0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a35be70) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a35be70) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x6fa199f55240, count: -16 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff80002a35b8d0 rbx 0xffff8000299eeddf rdx 0 rcx 0xffff80002a2e5508 rax 0xffff8000299edff0 r8 0x101010101010101 r9 0x8080808080808080 r10 0x4a1b9abbe77d3a06 r11 0x2165f94c14b79fbe r12 0xffff8000299eebe0 r13 0 r14 0 r15 0x1 rip 0xffffffff83152035 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80002a35b8c0 ss 0 db_enter+0x25: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor) tid=60928 pid=41033 tcnt=0 stat=onproc flags process=1008 proc=2000 runpri=32, usrpri=86, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0xffff80002a2e5508 scnt=-1 ecnt=1 forw=0xffffffffffffffff, list=0xffff80002a2e4aa8,0xffff80002a2e5a48 process=0xffff80002a2c1398 user=0xffff80002a356000, vmspace=0xfffffd8075a443e0 estcpu=36, cpticks=4, pctcpu=0.0, user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 49556 380911 74443 0 2 0x100002 ndp 74443 471769 34270 0 3 0x10008a sigsusp sh 72433 179227 21293 0 2 0 syz-executor 72433 452011 21293 0 2 0x4000000 syz-executor 18798 422406 73457 0 3 0x80 nanoslp syz-executor 18798 254758 73457 0 3 0x4000000 smrbar syz-executor 45530 267363 40388 0 2 0 syz-executor 45530 287583 40388 0 3 0x4000080 rest syz-executor 45530 250352 40388 0 3 0x4000080 pipewr syz-executor 34270 243888 319 0 3 0x82 wait syz-executor 35488 448857 319 0 2 0x2 syz-executor 38100 517329 319 0 3 0x82 nanoslp syz-executor 47036 288251 1 0 3 0x100083 ttyin getty 40636 22633 0 0 3 0x14200 bored sosplice 73457 494370 319 0 3 0x82 nanoslp syz-executor 63528 155736 319 0 2 0x3 syz-executor 40388 336833 319 0 2 0x3 syz-executor 21293 472970 319 0 7 0x3 syz-executor 37648 377099 319 0 2 0x3 syz-executor 319 375762 49232 0 3 0x82 kqread syz-executor 49232 451807 86777 0 3 0x10008a sigsusp ksh 86777 300118 63704 0 3 0x98 kqread sshd-session 63704 182625 76410 0 3 0x92 kqread sshd-session 76410 302228 1 0 3 0x88 kqread sshd 14630 508605 61846 74 3 0x1100092 bpf pflogd 61846 285780 1 0 3 0x80 sbwait pflogd 47425 413566 39482 73 3 0x1100090 kqread syslogd 39482 71424 1 0 3 0x100082 sbwait syslogd 4310 455654 1 0 3 0x100080 kqread resolvd 53927 324263 59459 77 3 0x100092 kqread dhcpleased 67942 338205 59459 77 3 0x100092 kqread dhcpleased 59459 488963 1 0 3 0x80 kqread dhcpleased 81204 492464 0 0 3 0x14200 bored smr 64225 138395 0 0 2 0x14200 zerothread 66109 390920 0 0 3 0x14200 aiodoned aiodoned 32351 4092 0 0 3 0x14200 syncer update 4432 125999 0 0 3 0x14200 cleaner cleaner 33883 78670 0 0 2 0x14200 reaper 73817 404636 0 0 3 0x14200 pgdaemon pagedaemon 81020 120020 0 0 3 0x14200 bored viomb 1881 340600 0 0 3 0x40014200 acpi0 acpi0 7781 179396 0 0 3 0x40014200 idle1 81667 491803 0 0 3 0x14200 bored softnet7 76361 260708 0 0 3 0x14200 bored softnet6 97622 292729 0 0 3 0x14200 bored softnet5 83950 174632 0 0 3 0x14200 bored softnet4 3982 188004 0 0 3 0x14200 bored softnet3 37020 280613 0 0 3 0x14200 bored softnet2 61357 217286 0 0 3 0x14200 bored softnet1 3837 254850 0 0 3 0x14200 bored softnet0 86242 62430 0 0 3 0x14200 smrbar systqmp 40906 130539 0 0 3 0x14200 bored systq 16898 170590 0 0 3 0x14200 tmoslp softclockmp 64266 149851 0 0 3 0x40014200 tmoslp softclock 82468 1820 0 0 3 0x40014200 idle0 1 389638 0 0 3 0x82 wait init 0 0 -1 0 3 0x10010200 scheduler swapper ddb{1}> show all locks Process 35488 (syz-executor) thread 0xffff80003c4ce570 (448857) Process 86242 (systqmp) thread 0xffff8000ffffe000 (62430) ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 10231 11040K 13021K 166960K 14555 0 pcb 17 15K 28K 166960K 613 0 rtable 188 12K 13K 166960K 844 0 pf 46 19K 21K 166960K 310 0 ifaddr 35 5K 8K 166960K 195 0 ifgroup 71 3K 3K 166960K 372 0 sysctl 4 1K 9K 166960K 33 0 counters 76 37K 38K 166960K 504 0 ioctlops 0 0K 4K 166960K 2107 0 iov 0 0K 32K 166960K 345 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1557 98K 99K 166960K 3921 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 8 0 VM map 2 1K 1K 166960K 2 0 sem 12 0K 0K 166960K 214 0 dirhash 12 2K 2K 166960K 51 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 17 61K 236K 166960K 3282 0 sigio 1 0K 0K 166960K 124 0 proc 73 115K 164K 166960K 1024 0 subproc 72 4K 4K 166960K 110 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 657 0 in_multi 57 4K 7K 166960K 253 0 ether_multi 1 0K 0K 166960K 36 0 mrt 2 0K 0K 166960K 27 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 91 413K 413K 166960K 91 0 exec 0 0K 1K 166960K 920 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 3 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 236 171K 187K 166960K 32055 0 UVM aobj 68 7K 7K 166960K 76 0 pinsyscall 43 86K 104K 166960K 4461 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 192 0 NDP 17 0K 2K 166960K 150 0 temp 85 8652K 8908K 166960K 170805 0 kqueue 14 22K 30K 166960K 612 0 SYN cache 2 16K 16K 166960K 2 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle plcache 128 26 0 0 1 0 1 1 0 8 0 rtpcb 120 394 0 390 4 3 1 3 0 8 0 rtentry 176 289 0 228 5 1 4 5 0 8 0 unpcb 144 2490 0 2473 14 12 2 6 0 8 1 syncache 336 6 0 6 2 2 0 1 0 8 0 tcpqe 32 1 0 1 1 1 0 1 0 8 0 tcpcb 736 910 0 904 11 9 2 6 0 8 0 arp 128 37 0 27 1 0 1 1 0 8 0 inpcb 328 3195 0 3182 31 29 2 10 0 8 0 nd6 144 31 0 19 1 0 1 1 0 8 0 pkpcb 40 94 0 94 8 7 1 1 0 8 1 kcovpl 48 12 0 4 1 0 1 1 0 8 0 mppekey 1024 1 0 1 1 1 0 1 0 8 0 ppxss 1192 185 0 184 2 1 1 1 0 8 0 pppxif 1504 12 0 11 5 4 1 1 0 8 0 pffrag 232 43 0 35 1 0 1 1 0 482 0 pffrnode 88 39 0 33 1 0 1 1 0 8 0 pffrent 40 80 0 71 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 pfrktable 1344 4 0 4 4 4 0 1 0 8 0 pftag 88 1 0 0 1 0 1 1 0 8 0 pfstitem 24 186 0 112 1 0 1 1 0 8 0 pfstkey 128 186 0 112 3 0 3 3 0 8 0 pfstate 384 186 0 112 8 0 8 8 0 8 0 pfrule 1344 24 0 19 2 1 1 2 0 8 0 rttmr 136 8 0 8 6 6 0 1 0 8 0 art_heap8 4096 2 0 0 2 0 2 2 0 8 0 art_heap4 256 1334 0 1073 47 26 21 43 0 8 3 art_table 40 1336 0 1073 7 2 5 7 0 8 0 art_node 32 286 0 234 1 0 1 1 0 8 0 sysvmsgpl 40 1 0 1 1 1 0 1 0 8 0 semapl 112 208 0 198 1 0 1 1 0 8 0 shmpl 112 73 0 8 2 0 2 2 0 8 0 dirhash 1024 43 0 26 3 0 3 3 0 8 0 dino2pl 256 7501 0 5987 97 1 96 96 0 8 0 ffsino 296 7501 0 5987 118 0 118 118 0 8 0 nchpl 144 12057 0 10357 64 0 64 64 0 8 0 rtmask 32 35 0 35 6 5 1 1 0 8 1 uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0 vnodes 216 5926 0 0 330 0 330 330 0 8 0 namei 1024 44795 0 44794 12 10 2 3 0 8 1 percpumem 16 267 0 214 1 0 1 1 0 8 0 kstatmem 264 258 0 222 4 1 3 3 0 8 0 acpiwqpl 32 2 0 2 1 0 1 1 1 8 1 scsiplug 72 5 0 5 5 5 0 1 0 8 0 scxspl 216 77731 0 77731 13 12 1 8 1 8 1 plimitpl 152 869 0 852 1 0 1 1 0 8 0 sigapl 424 3560 0 3506 10 3 7 9 0 8 0 knotepl 120 724 0 0 22 0 22 22 0 8 0 kqueuepl 224 1411 0 1398 19 18 1 9 0 8 0 pipepl 344 560 0 532 16 12 4 9 0 8 0 fdescpl 528 3510 0 3479 3 0 3 3 0 8 0 filepl 160 25675 0 25452 41 28 13 20 0 8 0 lockfpl 104 1999 0 1997 5 3 2 2 0 8 1 lockfspl 48 647 0 645 1 0 1 1 0 8 0 sessionpl 144 30 0 21 1 0 1 1 0 8 0 pgrppl 48 175 0 158 1 0 1 1 0 8 0 ucredpl 104 5168 0 5155 1 0 1 1 0 8 0 zombiepl 144 4748 0 4747 2 1 1 1 0 8 0 processpl 1248 3560 0 3506 6 0 6 6 0 8 0 procpl 664 8886 0 8827 10 3 7 8 0 8 1 sosppl 168 17 0 17 6 6 0 1 0 8 0 sockpl 752 6401 0 6367 56 51 5 18 0 8 0 mcl64k 65536 20 0 0 3 1 2 3 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 2 0 0 1 0 1 1 0 8 0 mcl9k 9216 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 4 0 0 1 0 1 1 0 8 0 mcl4k 4096 130 0 0 15 0 15 15 0 8 0 mcl2k2 2112 2 0 0 1 0 1 1 0 8 0 mcl2k 2048 96 0 0 7 0 7 7 0 8 0 mtagpl 96 11 0 0 1 0 1 1 0 8 0 mbufpl 256 1257 0 0 72 0 72 72 0 8 0 bufpl 280 31517 0 25374 441 1 440 440 0 8 0 anonpl 32 18834 0 0 152 0 152 152 0 246 0 amapchunkpl 152 109070 0 108535 72 41 31 39 0 158 5 amappl16 200 11066 0 10952 155 137 18 47 0 8 8 amappl15 192 35 0 34 1 0 1 1 0 8 0 amappl14 184 126 0 113 1 0 1 1 0 8 0 amappl13 176 7 0 7 1 1 0 1 0 8 0 amappl12 168 4239 0 4208 4 1 3 3 0 8 0 amappl11 160 55 0 41 1 0 1 1 0 8 0 amappl10 152 5 0 5 2 2 0 1 0 8 0 amappl9 144 255 0 254 2 1 1 1 0 8 0 amappl8 136 19 0 16 1 0 1 1 0 8 0 amappl7 128 121 0 107 1 0 1 1 0 8 0 amappl6 120 229 0 223 1 0 1 1 0 8 0 amappl5 112 213 0 202 1 0 1 1 0 8 0 amappl4 104 329 0 309 1 0 1 1 0 8 0 amappl3 96 22490 0 22390 5 1 4 4 0 8 0 amappl2 88 742 0 674 2 0 2 2 0 8 0 amappl1 80 21739 0 21116 16 3 13 15 0 8 0 amappl 88 30745 0 30588 5 0 5 5 0 92 0 dma4096 4096 1 0 1 1 1 0 1 0 8 0 dma2048 2048 1 0 1 1 1 0 1 0 8 0 dma1024 1024 3 0 2 1 0 1 1 0 8 0 dma256 256 6 0 6 1 1 0 1 0 8 0 dma128 128 256 0 256 4 3 1 1 0 8 1 dma64 64 7 0 7 2 2 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 19 0 18 1 0 1 1 0 8 0 aobjpl 72 75 0 8 2 0 2 2 0 8 0 uaddrrnd 24 3511 0 3480 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 3511 0 3480 1 0 1 1 0 8 0 vmmpekpl 168 27827 0 27782 3 0 3 3 0 8 0 vmmpepl 168 220766 0 218699 184 74 110 129 0 357 6 vmsppl 488 3510 0 3480 9 4 5 5 0 8 0 rwobjpl 80 61378 0 54330 168 17 151 159 0 8 0 pdppl 4096 7030 0 6960 120 46 74 86 0 8 4 pvpl 32 28037 0 0 226 0 226 226 0 265 0 pmappl 256 3510 0 3480 3 0 3 3 0 8 0 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 401 0 99 9 0 9 9 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff83837ff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x4f sys/dev/kcov.c:159 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff8398dd88) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff8398dd88) at __mp_lock+0x192 sys/kern/kern_lock.c:165 ktrsyscall(ffff8000ffff2fa0,5b,10,ffff80002a383780) at ktrsyscall+0x2c7 ktrwrite sys/kern/kern_ktrace.c:-1 [inline] ktrsyscall(ffff8000ffff2fa0,5b,10,ffff80002a383780) at ktrsyscall+0x2c7 sys/kern/kern_ktrace.c:183 syscall(ffff80002a383780) at syscall+0x304 mi_syscall sys/sys/syscall_mi.h:154 [inline] syscall(ffff80002a383780) at syscall+0x304 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7706923f93f0, count: 4 ddb{0}> trace x86_ipi_db(ffffffff83837ff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394 x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106 Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27 __sanitizer_cov_trace_pc() at __sanitizer_cov_trace_pc+0x4f sys/dev/kcov.c:159 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:847 Xsoftclock() at Xsoftclock+0x27 __mp_lock(ffffffff8398dd88) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:134 [inline] __mp_lock(ffffffff8398dd88) at __mp_lock+0x192 sys/kern/kern_lock.c:165 ktrsyscall(ffff8000ffff2fa0,5b,10,ffff80002a383780) at ktrsyscall+0x2c7 ktrwrite sys/kern/kern_ktrace.c:-1 [inline] ktrsyscall(ffff8000ffff2fa0,5b,10,ffff80002a383780) at ktrsyscall+0x2c7 sys/kern/kern_ktrace.c:183 syscall(ffff80002a383780) at syscall+0x304 mi_syscall sys/sys/syscall_mi.h:154 [inline] syscall(ffff80002a383780) at syscall+0x304 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7706923f93f0, count: -11 ddb{0}> machine ddbcpu 1 Stopped at db_enter+0x25: addq $0x8,%rsp db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff8336edd9) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833afff6,ffffffff833c2f1e,3b7,ffffffff833ed01e) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002a3cf508,ffffffff8336a3ec) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952 pppx_if_destroy(205b9a,ffff80002a3cf500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,83,2000,ffff80002a2e5508) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80002a35bb00) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805a4db2c8,83,fffffd80097fb208,ffff80002a2e5508) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805c9a0960,ffff80002a2e5508) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805c9a0960,ffff80002a2e5508) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80002a2e5508) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80002a2e5508,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80002a2e5508,ffff80002a35be70,ffff80002a35bdc0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 end trace frame: 0xffff80002a35be60, count: 0 ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff8336edd9) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff833afff6,ffffffff833c2f1e,3b7,ffffffff833ed01e) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80002a3cf508,ffffffff8336a3ec) at refcnt_finalize+0x1db sys/kern/kern_synch.c:952 pppx_if_destroy(205b9a,ffff80002a3cf500) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,83,2000,ffff80002a2e5508) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80002a35bb00) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffffd805a4db2c8,83,fffffd80097fb208,ffff80002a2e5508) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd805c9a0960,ffff80002a2e5508) at vn_closefile+0x12b sys/kern/vfs_vnops.c:615 fdrop(fffffd805c9a0960,ffff80002a2e5508) at fdrop+0x121 sys/kern/kern_descrip.c:1280 closef(fffffd805c9a0960,ffff80002a2e5508) at closef+0x192 sys/kern/kern_descrip.c:1264 fdfree(ffff80002a2e5508) at fdfree+0x116 sys/kern/kern_descrip.c:1195 exit1(ffff80002a2e5508,0,0,1) at exit1+0x576 sys/kern/kern_exit.c:215 sys_exit(ffff80002a2e5508,ffff80002a35be70,ffff80002a35bdc0) at sys_exit+0x1a sys/kern/kern_exit.c:-1 syscall(ffff80002a35be70) at syscall+0xb17 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80002a35be70) at syscall+0xb17 sys/arch/amd64/amd64/trap.c:748 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x6fa199f55240, count: -16