panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/multicore/kernel/sys/kern/kern_synch.c", line 959 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *301544 94894 0 0 0x4000000 1K syz-executor 326165 62947 0 0 0 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff834bceaa) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff834fbf34,ffffffff83507ca1,3bf,ffffffff835307be) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80003c3fab20,ffffffff834b0973) at refcnt_finalize+0x1e7 sys/kern/kern_synch.c:960 pppx_if_destroy(ffff800033b92000,ffff80003c3fab18) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,81,2000,ffff8000387b9a10) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c401370) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff1006ccc9448,81,fffff100097fd478,ffff8000387b9a10) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621 fdrop(fffff10069905a48,ffff8000387b9a10) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff10069905a48,ffff8000387b9a10) at closef+0x192 sys/kern/kern_descrip.c:1265 sys_closefrom(ffff8000387b9a10,ffff80003c401640,ffff80003c401590) at sys_closefrom+0x13c sys/kern/kern_descrip.c:1471 syscall(ffff80003c401640) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c401640) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf80c53d9df0, count: 1 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 959 ddb{1}> show kasan No such command ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff834bceaa) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff834fbf34,ffffffff83507ca1,3bf,ffffffff835307be) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80003c3fab20,ffffffff834b0973) at refcnt_finalize+0x1e7 sys/kern/kern_synch.c:960 pppx_if_destroy(ffff800033b92000,ffff80003c3fab18) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,81,2000,ffff8000387b9a10) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c401370) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff1006ccc9448,81,fffff100097fd478,ffff8000387b9a10) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621 fdrop(fffff10069905a48,ffff8000387b9a10) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff10069905a48,ffff8000387b9a10) at closef+0x192 sys/kern/kern_descrip.c:1265 sys_closefrom(ffff8000387b9a10,ffff80003c401640,ffff80003c401590) at sys_closefrom+0x13c sys/kern/kern_descrip.c:1471 syscall(ffff80003c401640) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c401640) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf80c53d9df0, count: -14 ddb{1}> show registers rdi 0 rsi 0x1 rbp 0xffff80003c401130 rbx 0xffff80002999ee07 rdx 0xffff800001601280 rcx 0xffff8000387b9a10 rax 0xffff80002999dff0 r8 0x101010101010101 r9 0x8080808080808080 r10 0xa426c37f60115791 r11 0x718d19d84cfecb37 r12 0xffff80002999ec08 r13 0 r14 0 r15 0x1 rip 0xffffffff827f3715 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80003c401120 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor) tid=301544 pid=94894 tcnt=3 stat=onproc flags process=0 proc=4000000 runpri=32, usrpri=72, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000387b8fb0,0xffff8000387b8d28 process=0xffff80002a37dcf8 user=0xffff80003c3fc000, vmspace=0xfffff1006ceed7b8 estcpu=22, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0 ddb{1}> ps PID TID PPID UID S PRLAGS PFLAGS WAIT COMMAND 28065 406035 67909 0 2 0 0 syz-executor 28065 436514 67909 0 2 0 0x4000000 syz-executor 68752 341829 70672 0 2 0 0 syz-executor 56513 413471 22019 0 2 0 0 syz-executor 56513 147078 22019 0 3 0 0x4000080 fsleep syz-executor 86460 146517 79659 0 2 0 0 syz-executor 86460 330247 79659 0 2 0 0x4000000 syz-executor 94894 30394 81871 0 2 0 0 syz-executor 94894 179774 81871 0 3 0 0x4000000 smrbar syz-executor *94894 301544 81871 0 7 0 0x4000000 syz-executor 62947 326165 35471 0 7 0 0 syz-executor 62947 396549 35471 0 3 0 0x4000080 lockf syz-executor 62947 231214 35471 0 3 0 0x4000080 lockf syz-executor 60701 202722 91715 0 2 0 0 syz-executor 60701 336341 91715 0 3 0 0x4000080 fsleep syz-executor 60701 303525 91715 0 3 0 0x4000080 fsleep syz-executor 19162 138533 28285 0 2 0 0 syz-executor 19162 68311 28285 0 2 0 0x4000000 syz-executor 22019 121347 68431 0 3 0x2 0x80 nanoslp syz-executor 91715 442633 68431 0 3 0x2 0x80 nanoslp syz-executor 81871 33908 68431 0 3 0x2 0x80 nanoslp syz-executor 35471 19712 68431 0 3 0x2 0x80 nanoslp syz-executor 67909 315392 68431 0 3 0x2 0x80 nanoslp syz-executor 79659 417278 68431 0 2 0x2 0 syz-executor 70672 478134 68431 0 3 0x2 0x80 nanoslp syz-executor 28285 148263 68431 0 3 0x2 0x80 nanoslp syz-executor 68431 18998 43801 0 3 0x2 0x80 kqread syz-executor 43801 342190 79056 0 3 0x100002 0x88 sigsusp ksh 79056 160273 46648 0 3 0x10 0x88 kqread sshd-session 46648 145389 40490 0 3 0x12 0x80 kqread sshd-session 2769 190609 1 0 3 0x100003 0x80 ttyin getty 40490 454241 1 0 3 0 0x88 kqread sshd 1093 226698 61732 74 3 0x1100012 0x80 bpf pflogd 61732 99579 1 0 3 0 0x80 sbwait pflogd 69229 312389 1346 73 3 0x1100010 0x80 kqread syslogd 1346 47869 1 0 3 0x100002 0x80 sbwait syslogd 4670 280432 1 0 3 0x100000 0x80 kqread resolvd 860 139372 55431 77 3 0x100012 0x80 kqread dhcpleased 84306 87895 55431 77 3 0x100012 0x80 kqread dhcpleased 55431 154718 1 0 3 0 0x80 kqread dhcpleased 99548 73483 0 0 3 0x14000 0x200 bored smr 12953 503896 0 0 2 0x14000 0x200 zerothread 51138 254563 0 0 3 0x14000 0x200 aiodoned aiodoned 87563 502243 0 0 3 0x14000 0x200 syncer update 58576 165434 0 0 3 0x14000 0x200 cleaner cleaner 23914 80841 0 0 3 0x14000 0x200 reaper reaper 82821 123830 0 0 3 0x14000 0x200 pgdaemon pagedaemon 52397 341928 0 0 3 0x14000 0x200 bored viomb 11893 312863 0 0 3 0x14000 0x40000200 acpi0 acpi0 55881 425395 0 0 3 0x14000 0x40000200 idle1 14269 457360 0 0 3 0x14000 0x200 bored softnet1 4939 470215 0 0 3 0x14000 0x200 bored softnet0 78549 494333 0 0 3 0x14000 0x200 smrbar systqmp 16092 383158 0 0 3 0x14000 0x200 bored systq 36216 143254 0 0 3 0x14000 0x200 tmoslp softclockmp 4892 122339 0 0 3 0x14000 0x40000200 tmoslp softclock 66907 28919 0 0 3 0x14000 0x40000200 idle0 1 140438 0 0 3 0x2 0x80 wait init 0 0 -1 0 3 0x10000 0x200 scheduler swapper ddb{1}> show all locks Process 94894 (syz-executor) thread 0xffff8000387b9a10 (301544) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff83aef6c0) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 vn_closefile+0x41 sys/kern/vfs_vnops.c:614 #2 fdrop+0x121 sys/kern/kern_descrip.c:1281 #3 closef+0x192 sys/kern/kern_descrip.c:1265 #4 sys_closefrom+0x13c sys/kern/kern_descrip.c:1471 #5 syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] #5 syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 #6 Xsyscall+0x128 Process 78549 (systqmp) thread 0xffff800045ffe530 (494333) shared rwlock systqmp r = 0 (0xffffffff839dd068) #0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline] #0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160 #1 taskq_thread+0x12a sys/kern/kern_task.c:442 #2 proc_trampoline+0x10 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 11062 12090K 12150K 166960K 12161 0 pcb 17 12K 12K 166960K 17 0 rtable 239 7K 7K 166960K 360 0 pf 40 18K 20K 166960K 53 0 ifaddr 46 7K 7K 166960K 48 0 ifgroup 62 2K 2K 166960K 62 0 sysctl 1 1K 9K 166960K 5 0 counters 76 37K 37K 166960K 76 0 ioctlops 0 0K 4K 166960K 1493 0 iov 0 0K 0K 166960K 1 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1298 82K 82K 166960K 1380 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 3 5K 5K 166960K 3 0 VM map 2 1K 1K 166960K 2 0 sem 2 0K 0K 166960K 2 0 dirhash 12 2K 2K 166960K 12 0 ACPI 1734 201K 291K 166960K 11964 0 file desc 18 65K 93K 166960K 158 0 proc 70 115K 180K 166960K 557 0 subproc 72 4K 4K 166960K 72 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 1 0 in_multi 100 7K 7K 166960K 102 0 ether_multi 1 0K 0K 166960K 2 0 mrt 0 0K 0K 166960K 4 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 37 175K 175K 166960K 37 0 exec 0 0K 1K 166960K 383 0 fusefs mount 1 32K 32K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 232 167K 177K 166960K 3253 0 UVM aobj 3 2K 2K 166960K 3 0 pinsyscall 43 86K 106K 166960K 1314 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 NDP 30 2K 2K 166960K 30 0 temp 35 9114K 9120K 166960K 3940 0 kqueue 16 26K 26K 166960K 30 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 28 0 0 1 0 1 1 0 8 0 rtpcb 120 34 0 31 1 0 1 1 0 8 0 rtentry 176 114 0 4 6 0 6 6 0 8 0 unpcb 144 55 0 37 1 0 1 1 0 8 0 syncache 336 4 0 4 1 0 1 1 0 8 1 tcpcb 736 13 0 7 1 0 1 1 0 8 0 arp 136 18 0 1 1 0 1 1 0 8 0 inpcb 328 71 0 62 1 0 1 1 0 8 0 nd6 152 24 0 0 1 0 1 1 0 8 0 kcovpl 48 8 0 0 1 0 1 1 0 8 0 ppxss 1192 2 0 0 1 0 1 1 0 8 0 pppxif 1576 1 0 0 1 0 1 1 0 8 0 pffrag 232 1 0 1 1 0 1 1 0 482 1 pffrnode 88 1 0 1 1 0 1 1 0 8 1 pffrent 40 4 0 4 1 0 1 1 0 8 1 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 19 0 0 1 0 1 1 0 8 0 pfstkey 128 19 0 0 1 0 1 1 0 8 0 pfstate 448 18 0 0 2 0 2 2 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 256 459 0 0 29 0 29 29 0 8 0 art_table 40 460 0 0 5 0 5 5 0 8 0 art_node 32 114 0 11 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1605 0 130 93 0 93 93 0 8 0 ffsino 296 1605 0 130 114 0 114 114 0 8 0 nchpl 144 1825 0 114 64 0 64 64 0 8 0 vnodes 216 1703 0 0 95 0 95 95 0 8 0 namei 1024 5541 0 5541 1 0 1 1 0 8 1 percpumem 16 54 0 0 1 0 1 1 0 8 0 kstatmem 264 31 0 0 3 0 3 3 0 8 0 scxspl 216 6156 0 6156 4 2 2 3 1 8 2 plimitpl 152 29 0 12 1 0 1 1 0 8 0 sigapl 424 475 0 427 7 0 7 7 0 8 1 knotepl 120 302 0 0 10 0 10 10 0 8 0 kqueuepl 224 28 0 14 1 0 1 1 0 8 0 pipepl 344 129 0 102 3 0 3 3 0 8 0 fdescpl 528 459 0 427 3 0 3 3 0 8 0 filepl 160 1639 0 1412 10 0 10 10 0 8 0 lockfpl 104 13 0 6 1 0 1 1 0 8 0 lockfspl 48 8 0 3 1 0 1 1 0 8 0 sessionpl 144 24 0 15 1 0 1 1 0 8 0 pgrppl 48 33 0 16 1 0 1 1 0 8 0 ucredpl 104 90 0 77 1 0 1 1 0 8 0 zombiepl 144 427 0 427 1 0 1 1 0 8 1 processpl 1232 475 0 427 5 0 5 5 0 8 1 procpl 664 514 0 456 5 0 5 5 0 8 0 sockpl 752 160 0 130 4 0 4 4 0 8 0 mcl64k 65536 3 0 0 1 0 1 1 0 8 0 mcl16k 16384 1 0 0 1 0 1 1 0 8 0 mcl12k 12288 1 0 0 1 0 1 1 0 8 0 mcl8k 8192 2 0 0 1 0 1 1 0 8 0 mcl4k 4096 116 0 0 15 0 15 15 0 8 0 mcl2k 2048 17 0 0 3 0 3 3 0 8 0 mextrefs 64 17 0 0 1 0 1 1 0 8 0 mtagpl 96 2 0 0 1 0 1 1 0 8 0 mbufpl 256 132 0 0 9 0 9 9 0 8 0 bufpl 272 2323 0 105 148 0 148 148 0 8 0 anonpl 32 3850 0 0 31 0 31 31 0 247 0 amapchunkpl 152 8810 0 8334 20 1 19 19 0 158 0 amappl16 200 1908 0 1889 5 0 5 5 0 8 3 amappl15 192 5 0 5 1 0 1 1 0 8 1 amappl14 184 431 0 430 1 0 1 1 0 8 0 amappl13 176 134 0 122 1 0 1 1 0 8 0 amappl12 168 708 0 678 2 0 2 2 0 8 0 amappl11 160 12 0 12 2 1 1 1 0 8 1 amappl10 152 64 0 49 1 0 1 1 0 8 0 amappl9 144 281 0 280 1 0 1 1 0 8 0 amappl8 136 105 0 103 1 0 1 1 0 8 0 amappl7 128 165 0 152 1 0 1 1 0 8 0 amappl6 120 152 0 151 1 0 1 1 0 8 0 amappl5 112 96 0 86 1 0 1 1 0 8 0 amappl4 104 295 0 273 1 0 1 1 0 8 0 amappl3 96 1589 0 1478 3 0 3 3 0 8 0 amappl2 88 539 0 479 2 0 2 2 0 8 0 amappl1 80 10469 0 9868 15 0 15 15 0 8 1 amappl 88 2516 0 2356 4 0 4 4 0 92 0 uvmvnodes 80 99 0 0 3 0 3 3 0 8 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 72 2 0 0 1 0 1 1 0 8 0 uaddrrnd 24 459 0 427 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 459 0 427 1 0 1 1 0 8 0 vmmpekpl 168 5784 0 5750 2 0 2 2 0 8 0 vmmpepl 168 39001 0 37078 86 0 86 86 0 357 1 vmsppl 488 458 0 427 5 0 5 5 0 8 1 rwobjpl 80 14834 0 13823 24 0 24 24 0 8 1 pdppl 4096 925 0 854 97 12 85 85 0 8 14 pvpl 32 10085 0 0 83 0 83 83 0 265 1 pmappl 256 458 0 427 3 0 3 3 0 8 0 extentpl 40 46 0 28 1 0 1 1 0 8 0 phpool 112 414 0 15 12 0 12 12 0 8 0 ddb{1}> machine ddbcpu 0 Stopped at x86_ipi_db+0x27: addq $0x8,%rsp x86_ipi_db(ffffffff838daff0) 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 __mp_lock(ffffffff83aeeec0) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:142 [inline] __mp_lock(ffffffff83aeeec0) at __mp_lock+0x192 sys/kern/kern_lock.c:173 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:862 Xsoftclock() at Xsoftclock+0x27 end of kernel end trace frame: 0x7cc23a78d810, count: 8 ddb{0}> trace x86_ipi_db(ffffffff838daff0) 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 __mp_lock(ffffffff83aeeec0) at __mp_lock+0x192 __mp_lock_spin sys/kern/kern_lock.c:142 [inline] __mp_lock(ffffffff83aeeec0) at __mp_lock+0x192 sys/kern/kern_lock.c:173 softintr_dispatch(0) at softintr_dispatch+0x125 sys/kern/kern_softintr.c:83 dosoftint(0) at dosoftint+0x54 sys/arch/amd64/amd64/intr.c:862 Xsoftclock() at Xsoftclock+0x27 end of kernel end trace frame: 0x7cc23a78d810, count: -7 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(ffffffff834bceaa) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff834fbf34,ffffffff83507ca1,3bf,ffffffff835307be) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80003c3fab20,ffffffff834b0973) at refcnt_finalize+0x1e7 sys/kern/kern_synch.c:960 pppx_if_destroy(ffff800033b92000,ffff80003c3fab18) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,81,2000,ffff8000387b9a10) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c401370) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff1006ccc9448,81,fffff100097fd478,ffff8000387b9a10) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621 fdrop(fffff10069905a48,ffff8000387b9a10) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff10069905a48,ffff8000387b9a10) at closef+0x192 sys/kern/kern_descrip.c:1265 sys_closefrom(ffff8000387b9a10,ffff80003c401640,ffff80003c401590) at sys_closefrom+0x13c sys/kern/kern_descrip.c:1471 syscall(ffff80003c401640) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c401640) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf80c53d9df0, count: 1 ddb{1}> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff834bceaa) at panic+0x1e5 sys/kern/subr_prf.c:198 __assert(ffffffff834fbf34,ffffffff83507ca1,3bf,ffffffff835307be) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff80003c3fab20,ffffffff834b0973) at refcnt_finalize+0x1e7 sys/kern/kern_synch.c:960 pppx_if_destroy(ffff800033b92000,ffff80003c3fab18) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(205b9a,81,2000,ffff8000387b9a10) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff80003c401370) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff1006ccc9448,81,fffff100097fd478,ffff8000387b9a10) at VOP_CLOSE+0x132 sys/kern/vfs_vops.c:156 vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff10069905a48,ffff8000387b9a10) at vn_closefile+0x12b sys/kern/vfs_vnops.c:621 fdrop(fffff10069905a48,ffff8000387b9a10) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff10069905a48,ffff8000387b9a10) at closef+0x192 sys/kern/kern_descrip.c:1265 sys_closefrom(ffff8000387b9a10,ffff80003c401640,ffff80003c401590) at sys_closefrom+0x13c sys/kern/kern_descrip.c:1471 syscall(ffff80003c401640) at syscall+0xbd4 mi_syscall sys/sys/syscall_mi.h:176 [inline] syscall(ffff80003c401640) at syscall+0xbd4 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xf80c53d9df0, count: -14