panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 955 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *153659 61778 0 0 0x4000000 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83488ad9) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff834c3d9f,ffffffff83523b79,3bb,ffffffff834fd361) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff8000314b71d0,ffffffff8347a970) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:956 pppx_if_destroy(285b9a,ffff8000314b71c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,41,2000,ffff8000344b8a80) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff8000390dba30) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff5806d298d88,41,fffff58007ffd7b8,ffff8000344b8a80) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156 vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d sys/kern/vfs_vnops.c:621 fdrop(fffff58073fe3268,ffff8000344b8a80) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff58073fe3268,ffff8000344b8a80) at closef+0x190 sys/kern/kern_descrip.c:1265 syscall(ffff8000390dbc80) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff8000390dbc80) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xef08cafe860, count: 2 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> ddb> set $lines = 0 ddb> set $maxwidth = 0 ddb> show panic *cpu0: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 955 ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83488ad9) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff834c3d9f,ffffffff83523b79,3bb,ffffffff834fd361) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff8000314b71d0,ffffffff8347a970) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:956 pppx_if_destroy(285b9a,ffff8000314b71c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,41,2000,ffff8000344b8a80) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff8000390dba30) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff5806d298d88,41,fffff58007ffd7b8,ffff8000344b8a80) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156 vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d sys/kern/vfs_vnops.c:621 fdrop(fffff58073fe3268,ffff8000344b8a80) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff58073fe3268,ffff8000344b8a80) at closef+0x190 sys/kern/kern_descrip.c:1265 syscall(ffff8000390dbc80) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff8000390dbc80) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xef08cafe860, count: -13 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff8000390db810 rbx 0 rdx 0 rcx 0 rax 0xffff8000344b8a80 r8 0x101010101010101 r9 0x8080808080808080 r10 0x5341b3496208caee r11 0x524fed77291452f r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff82f1a0d5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff8000390db800 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb> show proc PROC (syz-executor) tid=153659 pid=61778 tcnt=2 stat=onproc flags process=0 proc=4000000 runpri=32, usrpri=53, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff8000344b87e8,0xffff8000344b9cb8 process=0xffff80002a746888 user=0xffff8000390d6000, vmspace=0xfffff5806c91d468 estcpu=9, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 87436 185537 19396 0 2 0 syz-executor 59453 226646 3108 0 2 0 syz-executor 59453 14294 3108 0 3 0x4000080 fsleep syz-executor 46331 159715 89965 0 2 0 syz-executor 46331 281428 89965 0 3 0x4000080 fsleep syz-executor 25054 316931 36185 0 2 0 syz-executor 25054 248857 36185 0 3 0x4000080 fsleep syz-executor 61778 126666 53277 0 2 0 syz-executor *61778 153659 53277 0 7 0x4000000 syz-executor 44373 394262 16438 0 2 0 syz-executor 44373 90881 16438 0 3 0x4000080 fsleep syz-executor 44373 372276 16438 0 3 0x4000000 smrbar syz-executor 19396 57626 60152 0 2 0xc82 syz-executor 16438 449053 60152 0 2 0xc82 syz-executor 88980 461868 60152 0 2 0x2 syz-executor 53277 75132 60152 0 3 0x82 nanoslp syz-executor 89965 221269 60152 0 2 0xc82 syz-executor 3108 9745 60152 0 2 0xc82 syz-executor 36185 462705 60152 0 3 0x82 nanoslp syz-executor 42161 26287 60152 0 2 0x2 syz-executor 60152 358447 4227 0 3 0x82 kqread syz-executor 4227 508501 52827 0 3 0x10008a sigsusp ksh 52827 354778 79977 0 3 0x98 kqread sshd-session 79977 482045 21096 0 3 0x92 kqread sshd-session 85470 215692 1 0 3 0x100083 ttyin getty 21096 89037 1 0 3 0x88 kqread sshd 34937 254442 44749 73 3 0x1100090 kqread syslogd 44749 261254 1 0 3 0x100082 sbwait syslogd 53620 300473 1 0 3 0x100080 kqread resolvd 85832 422885 73960 77 3 0x100092 kqread dhcpleased 85980 405720 73960 77 3 0x100092 kqread dhcpleased 73960 41922 1 0 3 0x80 kqread dhcpleased 92389 156336 0 0 3 0x14200 bored smr 47168 190275 0 0 2 0x14200 zerothread 50452 377088 0 0 3 0x14200 aiodoned aiodoned 46062 168219 0 0 3 0x14200 syncer update 37790 321105 0 0 3 0x14200 cleaner cleaner 65843 355250 0 0 3 0x14200 reaper reaper 80388 470029 0 0 3 0x14200 pgdaemon pagedaemon 97517 29600 0 0 3 0x14200 bored viomb 81159 85407 0 0 3 0x40014200 acpi0 acpi0 35886 213185 0 0 3 0x14200 bored softnet0 65894 357450 0 0 3 0x14200 smrbar systqmp 80063 264716 0 0 3 0x14200 bored systq 83060 378499 0 0 3 0x40014200 tmoslp softclock 26273 302462 0 0 3 0x40014200 idle0 1 653 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb> show all locks No such command ddb> show malloc Type InUse MemUse HighUse Limit Requests Type Lim devbuf 11044 12233K 12296K 166960K 12143 0 pcb 17 12K 12K 166960K 27 0 rtable 241 7K 7K 166960K 360 0 pf 37 14K 14K 166960K 37 0 ifaddr 45 7K 8K 166960K 48 0 ifgroup 59 2K 2K 166960K 59 0 sysctl 1 1K 9K 166960K 5 0 counters 37 18K 18K 166960K 37 0 ioctlops 0 0K 4K 166960K 39 0 iov 0 0K 12K 166960K 4 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1294 81K 81K 166960K 1371 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 1K 166960K 2 0 VM map 2 1K 1K 166960K 2 0 sem 4 0K 0K 166960K 4 0 dirhash 12 2K 2K 166960K 12 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 16 57K 93K 166960K 156 0 proc 58 59K 91K 166960K 496 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 101 0 ether_multi 1 0K 0K 166960K 1 0 mrt 0 0K 0K 166960K 3 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 31 148K 148K 166960K 31 0 exec 0 0K 1K 166960K 365 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 203 158K 168K 166960K 3033 0 UVM aobj 3 2K 2K 166960K 3 0 pinsyscall 37 74K 92K 166960K 1256 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 4 0 NDP 30 2K 2K 166960K 30 0 temp 34 9102K 9108K 166960K 5086 0 kqueue 15 24K 24K 166960K 30 0 SYN cache 2 16K 16K 166960K 2 0 ddb> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle rtpcb 120 39 0 35 1 0 1 1 0 8 0 rtentry 136 113 0 2 4 0 4 4 0 8 0 unpcb 144 46 0 31 1 0 1 1 0 8 0 syncache 336 4 0 4 1 0 1 1 0 8 1 tcpcb 736 10 0 6 1 0 1 1 0 8 0 arp 96 18 0 0 1 0 1 1 0 8 0 inpcb 328 71 0 64 1 0 1 1 0 8 0 nd6 112 24 0 0 1 0 1 1 0 8 0 kcovpl 48 8 0 0 1 0 1 1 0 8 0 ppxss 1072 2 0 0 1 0 1 1 0 8 0 pppxif 1416 2 0 0 1 0 1 1 0 8 0 pfstscr 40 6 0 2 1 0 1 1 0 8 0 pfstitem 24 3 0 1 1 0 1 1 0 8 0 pfstkey 128 5 0 3 1 0 1 1 0 8 0 pfstate 384 3 0 1 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 458 0 0 29 0 29 29 0 8 0 art_table 40 459 0 0 5 0 5 5 0 8 0 art_node 32 113 0 11 1 0 1 1 0 8 0 semapl 72 2 0 0 1 0 1 1 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1587 0 125 92 0 92 92 0 8 0 ffsino 256 1587 0 125 92 0 92 92 0 8 0 nchpl 144 1809 0 115 63 0 63 63 0 8 0 vnodes 216 1682 0 0 94 0 94 94 0 8 0 namei 1024 5386 0 5385 2 0 2 2 0 8 1 kstatmem 264 27 0 0 2 0 2 2 0 8 0 scxspl 216 6132 0 6132 3 0 3 3 1 8 3 plimitpl 152 28 0 12 1 0 1 1 0 8 0 sigapl 424 451 0 410 6 0 6 6 0 8 1 knotepl 120 3028 0 2977 3 0 3 3 0 8 1 kqueuepl 184 31 0 18 1 0 1 1 0 8 0 pipepl 304 122 0 95 3 0 3 3 0 8 0 fdescpl 448 438 0 410 5 0 5 5 0 8 1 filepl 120 1545 0 1334 7 0 7 7 0 8 0 lockfpl 104 21 0 18 1 0 1 1 0 8 0 lockfspl 48 11 0 8 1 0 1 1 0 8 0 sessionpl 144 23 0 15 1 0 1 1 0 8 0 pgrppl 48 31 0 15 1 0 1 1 0 8 0 ucredpl 104 84 0 73 1 0 1 1 0 8 0 zombiepl 144 410 0 410 1 0 1 1 0 8 1 processpl 1152 451 0 410 4 0 4 4 0 8 0 procpl 664 480 0 433 5 0 5 5 0 8 0 sockpl 552 156 0 130 3 0 3 3 0 8 0 mcl64k 65536 2 0 2 1 0 1 1 0 8 1 mcl16k 16384 2 0 2 1 0 1 1 0 8 1 mcl12k 12288 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 5 0 5 1 0 1 1 0 8 1 mcl4k 4096 2528 0 2474 15 0 15 15 0 8 8 mcl2k 2048 121 0 118 1 0 1 1 0 8 0 mtagpl 96 4 0 4 1 0 1 1 0 8 1 mbufpl 256 4366 0 4218 11 0 11 11 0 8 1 bufpl 280 2271 0 102 155 0 155 155 0 8 0 anonpl 24 80092 0 77152 20 0 20 20 0 186 0 amapchunkpl 152 8089 0 7682 18 0 18 18 0 158 1 amappl16 200 1112 0 1097 4 0 4 4 0 8 3 amappl15 192 3 0 3 1 0 1 1 0 8 1 amappl14 184 406 0 405 1 0 1 1 0 8 0 amappl13 176 116 0 106 1 0 1 1 0 8 0 amappl12 168 673 0 646 2 0 2 2 0 8 0 amappl11 160 118 0 118 1 0 1 1 0 8 1 amappl10 152 74 0 64 1 0 1 1 0 8 0 amappl9 144 270 0 270 1 0 1 1 0 8 1 amappl8 136 97 0 96 1 0 1 1 0 8 0 amappl7 128 176 0 165 1 0 1 1 0 8 0 amappl6 120 167 0 164 1 0 1 1 0 8 0 amappl5 112 99 0 92 1 0 1 1 0 8 0 amappl4 104 257 0 241 1 0 1 1 0 8 0 amappl3 96 1596 0 1501 3 0 3 3 0 8 0 amappl2 88 519 0 468 2 0 2 2 0 8 0 amappl1 80 10207 0 9658 13 0 13 13 0 8 1 amappl 88 2343 0 2204 4 0 4 4 0 92 0 uvmvnodes 80 98 0 0 2 0 2 2 0 8 0 dma4096 4096 1 0 1 1 0 1 1 0 8 1 dma1024 1024 1 0 0 1 0 1 1 0 8 0 dma256 256 6 0 6 1 0 1 1 0 8 1 dma128 128 253 0 253 1 0 1 1 0 8 1 dma64 64 6 0 6 1 0 1 1 0 8 1 dma32 32 7 0 7 1 0 1 1 0 8 1 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 24 438 0 410 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 438 0 410 1 0 1 1 0 8 0 vmmpekpl 168 5455 0 5428 2 0 2 2 0 8 0 vmmpepl 168 37043 0 35366 78 0 78 78 0 357 2 vmsppl 368 437 0 410 4 0 4 4 0 8 1 rwobjpl 40 13657 0 12756 11 0 11 11 0 8 1 pdppl 4096 882 0 820 94 14 80 80 0 8 18 pvpl 32 204285 0 196239 71 0 71 71 0 265 3 pmappl 216 437 0 410 3 0 3 3 0 8 1 extentpl 40 45 0 27 1 0 1 1 0 8 0 phpool 112 357 0 14 10 0 10 10 0 8 0 ddb> machine ddbcpu 0 No such command ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83488ad9) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff834c3d9f,ffffffff83523b79,3bb,ffffffff834fd361) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff8000314b71d0,ffffffff8347a970) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:956 pppx_if_destroy(285b9a,ffff8000314b71c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,41,2000,ffff8000344b8a80) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff8000390dba30) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff5806d298d88,41,fffff58007ffd7b8,ffff8000344b8a80) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156 vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d sys/kern/vfs_vnops.c:621 fdrop(fffff58073fe3268,ffff8000344b8a80) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff58073fe3268,ffff8000344b8a80) at closef+0x190 sys/kern/kern_descrip.c:1265 syscall(ffff8000390dbc80) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff8000390dbc80) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xef08cafe860, count: -13 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83488ad9) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff834c3d9f,ffffffff83523b79,3bb,ffffffff834fd361) at __assert+0x29 sys/kern/subr_prf.c:-1 refcnt_finalize(ffff8000314b71d0,ffffffff8347a970) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:956 pppx_if_destroy(285b9a,ffff8000314b71c8) at pppx_if_destroy+0x3d sys/net/if_pppx.c:794 pppxclose(285b9a,41,2000,ffff8000344b8a80) at pppxclose+0xa0 sys/net/if_pppx.c:541 spec_close(ffff8000390dba30) at spec_close+0x417 sys/kern/spec_vnops.c:-1 VOP_CLOSE(fffff5806d298d88,41,fffff58007ffd7b8,ffff8000344b8a80) at VOP_CLOSE+0x129 sys/kern/vfs_vops.c:156 vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:298 [inline] vn_closefile(fffff58073fe3268,ffff8000344b8a80) at vn_closefile+0x11d sys/kern/vfs_vnops.c:621 fdrop(fffff58073fe3268,ffff8000344b8a80) at fdrop+0x121 sys/kern/kern_descrip.c:1281 closef(fffff58073fe3268,ffff8000344b8a80) at closef+0x190 sys/kern/kern_descrip.c:1265 syscall(ffff8000390dbc80) at syscall+0x962 mi_syscall sys/sys/syscall_mi.h:-1 [inline] syscall(ffff8000390dbc80) at syscall+0x962 sys/arch/amd64/amd64/trap.c:783 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0xef08cafe860, count: -13