panic: kernel diagnostic assertion "refs != ~0" failed: file "/syzkaller/managers/main/kernel/sys/kern/kern_synch.c", line 944 Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *292064 73702 0 0 0x4000000 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83402da5) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff833b2723,ffffffff832fcaa4,3b0,ffffffff833b5ca5) at __assert+0x29 refcnt_finalize(ffff80003c96f068,ffffffff832fcb7e) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945 pppx_if_destroy(ffff800036128000,ffff80003c96f060) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806 pppxclose(205b9a,1,2000,ffff80003a5334a8) at pppxclose+0xa0 sys/net/if_pppx.c:553 spec_close(ffff80003c95d280) at spec_close+0x412 VOP_CLOSE(fffffd806649e5e8,1,fffffd807f7d7548,ffff80003a5334a8) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156 vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615 fdrop(fffffd807bca3bd0,ffff80003a5334a8) at fdrop+0x126 sys/kern/kern_descrip.c:1265 closef(fffffd807bca3bd0,ffff80003a5334a8) at closef+0x18d sys/kern/kern_descrip.c:1249 syscall(ffff80003c95d4e0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x13a82c06250, 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 944 ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:438 panic(ffffffff83402da5) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff833b2723,ffffffff832fcaa4,3b0,ffffffff833b5ca5) at __assert+0x29 refcnt_finalize(ffff80003c96f068,ffffffff832fcb7e) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945 pppx_if_destroy(ffff800036128000,ffff80003c96f060) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806 pppxclose(205b9a,1,2000,ffff80003a5334a8) at pppxclose+0xa0 sys/net/if_pppx.c:553 spec_close(ffff80003c95d280) at spec_close+0x412 VOP_CLOSE(fffffd806649e5e8,1,fffffd807f7d7548,ffff80003a5334a8) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156 vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615 fdrop(fffffd807bca3bd0,ffff80003a5334a8) at fdrop+0x126 sys/kern/kern_descrip.c:1265 closef(fffffd807bca3bd0,ffff80003a5334a8) at closef+0x18d sys/kern/kern_descrip.c:1249 syscall(ffff80003c95d4e0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x13a82c06250, count: -13 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80003c95d060 rbx 0xffffffff81d0a460 pppxclose rdx 0xffff800001442f40 rcx 0 rax 0xffff80003a5334a8 r8 0 r9 0x8080808080808080 r10 0xe711c37d9961ae97 r11 0x84443b7838dc3c05 r12 0 r13 0 r14 0 r15 0x1 rip 0xffffffff8118f6d5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80003c95d050 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb> show proc PROC (syz-executor) tid=292064 pid=73702 tcnt=3 stat=onproc flags process=0 proc=4000000 runpri=32, usrpri=86, slppri=32, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80003a532cf8,0xffffffff838e7678 process=0xffff800035d24018 user=0xffff80003c958000, vmspace=0xfffffd806c0b5448 estcpu=36, cpticks=1, pctcpu=0.0, user=0, sys=1, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 73702 130070 62089 0 2 0 syz-executor 73702 289309 62089 0 3 0x4000000 smrbar syz-executor *73702 292064 62089 0 7 0x4000000 syz-executor 46718 257725 35384 0 3 0x80 nanoslp syz-executor 46718 335140 35384 0 3 0x4000080 lockf syz-executor 46718 261542 35384 0 3 0x4000080 fsleep syz-executor 62888 502120 7737 0 3 0x80 nanoslp syz-executor 62888 378756 7737 0 3 0x4000080 kqsel syz-executor 62888 463324 7737 0 3 0x4000080 fsleep syz-executor 2709 216293 12929 0 2 0x480 syz-executor 2709 90622 12929 0 3 0x4000080 fifor syz-executor 2709 100265 12929 0 3 0x4000080 fifor syz-executor 2709 304775 12929 0 3 0x4000080 fsleep syz-executor 77682 199030 95031 60928 3 0x90 nanoslp syz-executor 77682 276742 95031 60928 3 0x4000090 msgwait syz-executor 77682 262008 95031 60928 3 0x4000090 fsleep syz-executor 52172 151234 60340 0 2 0x480 syz-executor 52172 181680 60340 0 3 0x4000080 kqread syz-executor 3773 456518 90499 0 2 0x480 syz-executor 3773 264647 90499 0 3 0x4000080 netacc syz-executor 3773 302994 90499 0 3 0x4000080 fsleep syz-executor 92374 356799 0 0 3 0x14200 bored sosplice 35384 87141 59659 0 2 0x482 syz-executor 95031 444016 59659 0 2 0x482 syz-executor 62089 37940 59659 0 3 0x82 nanoslp syz-executor 40100 11729 59659 0 3 0x82 wait syz-executor 90499 118005 59659 0 2 0x482 syz-executor 12929 294586 59659 0 2 0x482 syz-executor 7737 34386 59659 0 3 0x82 nanoslp syz-executor 60340 195285 59659 0 2 0x482 syz-executor 59659 117689 39510 0 3 0x82 kqread syz-executor 39510 500927 76850 0 3 0x10008a sigsusp ksh 76850 459780 6940 0 3 0x98 kqread sshd-session 6940 55532 46428 0 3 0x92 kqread sshd-session 6371 444308 1 0 3 0x100083 ttyin getty 46428 176545 1 0 3 0x88 kqread sshd 71782 498781 88518 73 3 0x1100090 kqread syslogd 88518 255594 1 0 3 0x100082 sbwait syslogd 1436 449359 1 0 3 0x100080 kqread resolvd 87878 433574 20951 77 3 0x100092 kqread dhcpleased 89458 69282 20951 77 3 0x100092 kqread dhcpleased 20951 516259 1 0 3 0x80 kqread dhcpleased 46105 118300 0 0 3 0x14200 bored smr 16077 55925 0 0 2 0x14200 zerothread 84040 136754 0 0 3 0x14200 aiodoned aiodoned 29331 30591 0 0 3 0x14200 syncer update 85018 199137 0 0 3 0x14200 cleaner cleaner 7907 215737 0 0 3 0x14200 reaper reaper 88126 427641 0 0 3 0x14200 pgdaemon pagedaemon 59191 12211 0 0 3 0x14200 bored viomb 30186 276102 0 0 3 0x40014200 acpi0 acpi0 34627 170396 0 0 3 0x14200 bored softnet3 13157 260961 0 0 3 0x14200 bored softnet2 10078 274813 0 0 3 0x14200 bored softnet1 66182 166369 0 0 3 0x14200 bored softnet0 94651 120859 0 0 3 0x14200 bored systqmp 12705 248954 0 0 3 0x14200 bored systq 46404 147065 0 0 2 0x40014200 softclock 21684 517828 0 0 3 0x40014200 idle0 1 189083 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 10181 11101K 11428K 166960K 11694 0 pcb 19 14K 16K 166960K 139 0 rtable 201 6K 7K 166960K 381 0 pf 32 13K 20K 166960K 50 0 ifaddr 39 6K 7K 166960K 54 0 ifgroup 51 2K 2K 166960K 69 0 sysctl 1 1K 1K 166960K 1 0 counters 31 17K 17K 166960K 38 0 ioctlops 0 0K 4K 166960K 47 0 iov 0 0K 20K 166960K 21 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1400 88K 88K 166960K 1671 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 5K 166960K 5 0 VM map 2 1K 1K 166960K 2 0 sem 5 0K 0K 166960K 5 0 dirhash 12 2K 2K 166960K 21 0 ACPI 1692 195K 286K 166960K 12470 0 file desc 18 65K 97K 166960K 393 0 sigio 0 0K 0K 166960K 3 0 proc 60 59K 124K 166960K 504 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 58 0 in_multi 78 5K 7K 166960K 111 0 ether_multi 1 0K 0K 166960K 4 0 mrt 1 0K 0K 166960K 3 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 79 360K 360K 166960K 79 0 exec 0 0K 1K 166960K 372 0 fusefs mount 1 32K 32K 166960K 1 0 pfkey data 0 0K 0K 166960K 1 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 235 73K 77K 166960K 5012 0 UVM aobj 4 2K 4K 166960K 8 0 pinsyscall 39 78K 96K 166960K 1415 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 1 0K 0K 166960K 14 0 NDP 11 0K 2K 166960K 32 0 temp 48 8629K 8695K 166960K 19614 0 kqueue 16 26K 30K 166960K 90 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 54 0 49 1 0 1 1 0 8 0 rtentry 136 116 0 25 4 0 4 4 0 8 0 unpcb 144 565 0 544 6 0 6 6 0 8 4 syncache 336 4 0 4 1 0 1 1 0 8 1 tcpcb 808 119 0 114 7 0 7 7 0 8 6 arp 88 18 0 2 1 0 1 1 0 8 0 inpcb 344 420 0 408 7 0 7 7 0 8 5 nd6 104 25 0 6 1 0 1 1 0 8 0 pkpcb 40 2 0 2 1 0 1 1 0 8 1 kcovpl 48 8 0 0 1 0 1 1 0 8 0 ppxss 1072 5 0 4 1 0 1 1 0 8 0 pppxif 1376 3 0 2 1 0 1 1 0 8 0 pfstkey 128 2 0 2 1 0 1 1 0 8 1 pfstate 344 1 0 1 1 0 1 1 0 8 1 pfrule 1344 2 0 2 1 0 1 1 0 8 1 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 472 0 102 29 0 29 29 0 8 3 art_table 32 473 0 102 4 0 4 4 0 8 0 art_node 16 114 0 31 1 0 1 1 0 8 0 sysvmsgpl 40 8 0 6 1 0 1 1 0 8 0 semapl 112 3 0 0 1 0 1 1 0 8 0 shmpl 112 5 0 4 1 0 1 1 0 8 0 dirhash 1024 23 0 6 3 0 3 3 0 8 0 dino2pl 256 2054 0 555 95 0 95 95 0 8 0 ffsino 248 2054 0 555 95 0 95 95 0 8 0 nchpl 144 2632 0 948 63 0 63 63 0 8 0 uvmvnodes 80 2349 0 0 48 0 48 48 0 8 0 vnodes 216 2349 0 0 131 0 131 131 0 8 0 namei 1024 8534 0 8534 2 0 2 2 0 8 2 kstatmem 264 32 0 10 2 0 2 2 0 8 0 scsiplug 72 2 0 2 1 0 1 1 0 8 1 scxspl 216 7853 0 7853 3 0 3 3 1 8 3 plimitpl 152 169 0 151 1 0 1 1 0 8 0 sigapl 424 673 0 626 7 0 7 7 0 8 1 futexpl 64 4473 0 4468 1 0 1 1 0 8 0 knotepl 120 86117 0 86066 16 6 10 16 0 8 7 kqueuepl 184 189 0 108 4 0 4 4 0 8 0 pipepl 296 129 0 101 3 0 3 3 0 8 0 fdescpl 440 654 0 624 5 0 5 5 0 8 1 filepl 120 3905 0 3598 12 0 12 12 0 8 2 lockfpl 104 66 0 60 1 0 1 1 0 8 0 lockfspl 48 29 0 24 1 0 1 1 0 8 0 sessionpl 144 21 0 13 1 0 1 1 0 8 0 pgrppl 48 33 0 17 1 0 1 1 0 8 0 ucredpl 104 447 0 435 1 0 1 1 0 8 0 zombiepl 144 627 0 626 1 0 1 1 0 8 0 processpl 1104 673 0 626 4 0 4 4 0 8 0 procpl 656 1082 0 1021 6 0 6 6 0 8 0 sosppl 168 2 0 2 1 0 1 1 0 8 1 sockpl 528 1045 0 1007 11 1 10 11 0 8 7 mcl64k 65536 6 0 6 1 0 1 1 0 8 1 mcl16k 16384 1 0 1 1 0 1 1 0 8 1 mcl12k 12288 3 0 3 1 0 1 1 0 8 1 mcl9k 9216 1 0 1 1 0 1 1 0 8 1 mcl8k 8192 11 0 11 1 0 1 1 0 8 1 mcl4k 4096 2772 0 2720 14 0 14 14 0 8 6 mcl2k 2048 394 0 390 2 0 2 2 0 8 1 mtagpl 96 14 0 4 1 0 1 1 0 8 0 mbufpl 256 7237 0 7069 18 0 18 18 0 8 7 bufpl 280 2710 0 125 185 0 185 185 0 8 0 anonpl 24 128225 0 122820 57 0 57 57 0 187 17 amapchunkpl 152 16271 0 15670 31 0 31 31 0 158 7 amappl16 200 2534 0 2445 18 0 18 18 0 8 11 amappl15 192 4 0 4 1 0 1 1 0 8 1 amappl14 184 105 0 95 1 0 1 1 0 8 0 amappl13 176 25 0 25 1 0 1 1 0 8 1 amappl12 168 1280 0 1250 3 0 3 3 0 8 1 amappl11 160 48 0 38 1 0 1 1 0 8 0 amappl10 152 7 0 6 1 0 1 1 0 8 0 amappl9 144 246 0 246 1 0 1 1 0 8 1 amappl8 136 48 0 46 1 0 1 1 0 8 0 amappl7 128 96 0 85 1 0 1 1 0 8 0 amappl6 120 167 0 164 1 0 1 1 0 8 0 amappl5 112 120 0 114 1 0 1 1 0 8 0 amappl4 104 287 0 270 1 0 1 1 0 8 0 amappl3 96 2892 0 2773 4 0 4 4 0 8 0 amappl2 88 616 0 560 2 0 2 2 0 8 0 amappl1 80 8156 0 7632 13 0 13 13 0 8 1 amappl 88 4649 0 4462 5 0 5 5 0 92 0 dma65536 65536 1 0 1 1 0 1 1 0 8 1 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 128 254 0 254 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 7 0 4 1 0 1 1 0 8 0 uaddrrnd 24 654 0 624 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 654 0 624 1 0 1 1 0 8 0 vmmpekpl 168 6514 0 6482 2 0 2 2 0 8 0 vmmpepl 168 45861 0 43989 92 0 92 92 0 357 10 vmsppl 360 653 0 624 4 0 4 4 0 8 1 rwobjpl 32 17562 0 14274 28 0 28 28 0 8 1 pdppl 4096 1314 0 1248 98 32 66 82 0 8 0 pvpl 32 306295 0 295065 121 0 121 121 0 265 23 pmappl 216 653 0 624 3 0 3 3 0 8 0 extentpl 40 55 0 38 1 0 1 1 0 8 0 phpool 112 277 0 32 8 0 8 8 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(ffffffff83402da5) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff833b2723,ffffffff832fcaa4,3b0,ffffffff833b5ca5) at __assert+0x29 refcnt_finalize(ffff80003c96f068,ffffffff832fcb7e) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945 pppx_if_destroy(ffff800036128000,ffff80003c96f060) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806 pppxclose(205b9a,1,2000,ffff80003a5334a8) at pppxclose+0xa0 sys/net/if_pppx.c:553 spec_close(ffff80003c95d280) at spec_close+0x412 VOP_CLOSE(fffffd806649e5e8,1,fffffd807f7d7548,ffff80003a5334a8) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156 vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615 fdrop(fffffd807bca3bd0,ffff80003a5334a8) at fdrop+0x126 sys/kern/kern_descrip.c:1265 closef(fffffd807bca3bd0,ffff80003a5334a8) at closef+0x18d sys/kern/kern_descrip.c:1249 syscall(ffff80003c95d4e0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x13a82c06250, 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(ffffffff83402da5) at panic+0x1cf sys/kern/subr_prf.c:198 __assert(ffffffff833b2723,ffffffff832fcaa4,3b0,ffffffff833b5ca5) at __assert+0x29 refcnt_finalize(ffff80003c96f068,ffffffff832fcb7e) at refcnt_finalize+0x1c8 sys/kern/kern_synch.c:945 pppx_if_destroy(ffff800036128000,ffff80003c96f060) at pppx_if_destroy+0x3d sys/net/if_pppx.c:806 pppxclose(205b9a,1,2000,ffff80003a5334a8) at pppxclose+0xa0 sys/net/if_pppx.c:553 spec_close(ffff80003c95d280) at spec_close+0x412 VOP_CLOSE(fffffd806649e5e8,1,fffffd807f7d7548,ffff80003a5334a8) at VOP_CLOSE+0x12a sys/kern/vfs_vops.c:156 vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d vn_close sys/kern/vfs_vnops.c:292 [inline] vn_closefile(fffffd807bca3bd0,ffff80003a5334a8) at vn_closefile+0x11d sys/kern/vfs_vnops.c:615 fdrop(fffffd807bca3bd0,ffff80003a5334a8) at fdrop+0x126 sys/kern/kern_descrip.c:1265 closef(fffffd807bca3bd0,ffff80003a5334a8) at closef+0x18d sys/kern/kern_descrip.c:1249 syscall(ffff80003c95d4e0) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x13a82c06250, count: -13