panic: witness_warn Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *466329 5252 0 0 0x4000000 0 syz-executor0 246563 43510 0 0x2 0 1 syz-executor0 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_warn(564be0649ea60970,0,ffff800020b939e0) at witness_warn+0x700 witness_debugger sys/kern/subr_witness.c:2549 [inline] witness_warn(564be0649ea60970,0,ffff800020b939e0) at witness_warn+0x700 sys/kern/subr_witness.c:1465 userret(f494621538a35ff) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(c7f65ce329c6b23d) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(c7f65ce329c6b23d) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,1262718b1a0) at Xsyscall+0x128 end of kernel end trace frame: 0x1287a2eb450, count: 9 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{0}> ddb{0}> set $lines = 0 ddb{0}> show panic witness_warn ddb{0}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:399 panic() at panic+0x16c sys/kern/subr_prf.c:208 witness_warn(564be0649ea60970,0,ffff800020b939e0) at witness_warn+0x700 witness_debugger sys/kern/subr_witness.c:2549 [inline] witness_warn(564be0649ea60970,0,ffff800020b939e0) at witness_warn+0x700 sys/kern/subr_witness.c:1465 userret(f494621538a35ff) at userret+0x361 sys/kern/kern_sig.c:1899 syscall(c7f65ce329c6b23d) at syscall+0x680 mi_syscall_return sys/sys/syscall_mi.h:122 [inline] syscall(c7f65ce329c6b23d) at syscall+0x680 sys/arch/amd64/amd64/trap.c:605 Xsyscall(6,5,c,0,3,1262718b1a0) at Xsyscall+0x128 end of kernel end trace frame: 0x1287a2eb450, count: -6 ddb{0}> show registers rdi 0xffffffff81724177 db_enter+0x17 rsi 0x470a __ALIGN_SIZE+0x370a rbp 0xffff800020c92fe0 rbx 0xffff800020c93080 rdx 0x470b __ALIGN_SIZE+0x370b rcx 0xffff800000d46000 rax 0xffff800000d46000 r8 0xffffffff81d43064 kprintf+0x174 r9 0x1 r10 0x1d05874aa7a0ab3 r11 0x680d9692ed1fdc07 r12 0x3000000008 r13 0xffff800020c92ff0 r14 0x100 r15 0x1 rip 0xffffffff81724178 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800020c92fd0 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{0}> show proc PROC (syz-executor0) pid=466329 stat=onproc flags process=0 proc=4000000 pri=32, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020b93c38,0xffffffff822e8af0 process=0xffff800020b94010 user=0xffff800020c8e000, vmspace=0xfffffd807f00c2d0 estcpu=36, cpticks=3, pctcpu=0.0 user=0, sys=3, intr=0 ddb{0}> ps PID TID PPID UID S FLAGS WAIT COMMAND 5252 287167 43510 0 2 0 syz-executor0 5252 159406 43510 0 3 0x4000080 fsleep syz-executor0 5252 113204 43510 0 2 0x4000000 syz-executor0 * 5252 466329 43510 0 7 0x4000000 syz-executor0 44450 363395 1 0 3 0x100083 ttyin getty 18752 247171 0 0 3 0x14200 bored sosplice 20447 279937 14592 0 2 0x2 syz-executor1 43510 246563 14592 0 7 0x2 syz-executor0 14592 489425 33108 0 3 0x82 thrsleep syz-fuzzer 14592 48157 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 140318 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 235066 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 72809 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 44244 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 142163 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 49736 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 18198 33108 0 3 0x4000082 kqread syz-fuzzer 14592 174119 33108 0 3 0x4000082 thrsleep syz-fuzzer 14592 386576 33108 0 3 0x4000082 thrsleep syz-fuzzer 33108 323805 20728 0 3 0x10008a pause ksh 20728 495190 62025 0 3 0x92 select sshd 62025 58822 1 0 3 0x80 select sshd 48072 249084 67120 73 3 0x100010 ffs_fsync syslogd 67120 146098 1 0 3 0x100082 netio syslogd 26208 5919 1 77 3 0x100090 poll dhclient 75281 312910 1 0 3 0x80 poll dhclient 26316 114113 0 0 3 0x14200 pgzero zerothread 97289 152273 0 0 3 0x14200 aiodoned aiodoned 72297 383988 0 0 3 0x14200 syncer update 17128 166002 0 0 3 0x14200 cleaner cleaner 60368 480624 0 0 3 0x14200 reaper reaper 58320 97239 0 0 3 0x14200 pgdaemon pagedaemon 85320 128644 0 0 3 0x14200 bored crynlk 17605 516260 0 0 3 0x14200 bored crypto 86953 438161 0 0 3 0x40014200 acpi0 acpi0 2685 331072 0 0 3 0x40014200 idle1 56958 459081 0 0 3 0x14200 bored softnet 44132 187395 0 0 3 0x14200 bored systqmp 61359 202886 0 0 3 0x14200 bored systq 86541 290681 0 0 3 0x40014200 bored softclock 1598 50340 0 0 3 0x40014200 idle0 1 383587 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{0}> show all locks CPU 1: exclusive sched_lock &sched_lock r = 0 (0xffffffff8231c688) locked @ /syzkaller/managers/multicore/kernel/sys/kern/sched_bsd.c:323 Process 5252 (syz-executor0) thread 0xffff800020b939e0 (466329) exclusive rrwlock inode r = 0 (0xfffffd806e6d6c48) locked @ /syzkaller/managers/multicore/kernel/sys/ufs/ufs/ufs_vnops.c:1547 Process 48072 (syslogd) thread 0xffff800020be5c30 (249084) exclusive rrwlock inode r = 0 (0xfffffd806eb911a8) locked @ /syzkaller/managers/multicore/kernel/sys/ufs/ufs/ufs_vnops.c:1547 ddb{0}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9546 10463K 10479K 78643K 12190 0 0 pcb 23 9K 11K 78643K 3498 0 0 rtable 100 3K 4K 78643K 882 0 0 ifaddr 62 17K 19K 78643K 472 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 2K 78643K 54 0 0 iov 0 0K 32K 78643K 643 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1185 74K 76K 78643K 5182 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 5K 78643K 136 0 0 VM map 2 1K 1K 78643K 2 0 0 sem 12 1K 1K 78643K 664 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1792 194K 288K 78643K 12592 0 0 file desc 5 13K 25K 78643K 6590 0 0 sigio 0 0K 0K 78643K 96 0 0 proc 42 38K 70K 78643K 1159 0 0 subproc 64 65538K 67586K 78643K 89 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 0 0K 0K 78643K 872 0 0 in_multi 33 2K 2K 78643K 352 0 0 ether_multi 1 0K 0K 78643K 52 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 138 609K 609K 78643K 138 0 0 exec 0 0K 1K 78643K 636 0 0 pfkey data 0 0K 0K 78643K 2 0 0 pagedep 1 8K 8K 78643K 1 0 0 inodedep 1 32K 32K 78643K 1 0 0 newblk 1 0K 0K 78643K 1 0 0 VM swap 7 26K 26K 78643K 7 0 0 UVM amap 120 22K 31K 78643K 21907 0 0 UVM aobj 130 4K 4K 78643K 145 0 0 memdesc 1 4K 4K 78643K 1 0 0 crypto data 1 1K 1K 78643K 1 0 0 ip6_options 0 0K 1K 78643K 176 0 0 NDP 13 0K 0K 78643K 134 0 0 temp 177 2363K 2435K 78643K 20078 0 0 kqueue 0 0K 0K 78643K 100 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{0}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 4 0 0 1 0 1 1 0 8 0 inpcbpl 280 2819 0 2812 1 0 1 1 0 8 0 plimitpl 152 87 0 80 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtentry 112 41 0 1 2 0 2 2 0 8 0 syncache 264 4 0 4 1 1 0 1 0 8 0 tcpcb 544 1044 0 1040 1 0 1 1 0 8 0 nd6 48 4 0 0 1 0 1 1 0 8 0 ppxss 1128 63 0 63 27 27 0 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 185 0 0 12 0 12 12 0 8 0 art_table 32 186 0 0 2 0 2 2 0 8 0 art_node 16 40 0 6 1 0 1 1 0 8 0 sysvmsgpl 40 39 0 21 1 0 1 1 0 8 0 semupl 112 1 0 1 1 1 0 1 0 8 0 semapl 112 660 0 650 1 0 1 1 0 8 0 shmpl 112 143 0 15 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 14158 0 12636 50 0 50 50 0 8 0 ffsino 272 14158 0 12636 104 2 102 102 0 8 0 nchpl 144 23951 0 22372 59 0 59 59 0 8 0 uvmvnodes 72 5926 0 0 108 0 108 108 0 8 0 vnodes 200 5926 0 0 312 0 312 312 0 8 0 namei 1024 74706 0 74706 1 0 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 scsiplug 64 18 0 18 11 11 0 1 0 8 0 scxspl 192 69474 0 69473 25 24 1 6 0 8 0 sigapl 432 6758 0 6745 2 0 2 2 0 8 0 futexpl 56 80624 0 80623 2 1 1 1 0 8 0 knotepl 112 1837 0 1810 13 12 1 2 0 8 0 kqueuepl 104 2301 0 2299 1 0 1 1 0 8 0 pipepl 112 4448 0 4429 18 17 1 2 0 8 0 fdescpl 488 6759 0 6745 3 1 2 3 0 8 0 filepl 152 42836 0 42733 18 13 5 7 0 8 0 lockfpl 96 1976 0 1976 16 15 1 1 0 8 1 lockfspl 24 3325 0 3325 16 15 1 1 0 8 1 sessionpl 112 18 0 8 1 0 1 1 0 8 0 pgrppl 48 84 0 74 1 0 1 1 0 8 0 ucredpl 96 14199 0 14192 1 0 1 1 0 8 0 zombiepl 144 6745 0 6744 2 1 1 1 0 8 0 processpl 840 6774 0 6744 4 0 4 4 0 8 0 procpl 600 20964 0 20921 4 0 4 4 0 8 0 sosppl 128 113 0 113 31 30 1 1 0 8 1 sockpl 384 6174 0 6157 9 6 3 4 0 8 1 mcl64k 65536 899 0 0 88 59 29 65 0 8 0 mcl16k 16384 4 0 0 1 0 1 1 0 8 0 mcl12k 12288 33 0 0 2 1 1 2 0 8 0 mcl9k 9216 32 0 0 2 0 2 2 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 25 0 0 4 1 3 3 0 8 0 mcl2k2 2112 6 0 0 1 0 1 1 0 8 0 mcl2k 2048 138 0 0 14 3 11 14 0 8 0 mtagpl 80 1 0 0 1 0 1 1 0 8 0 mbufpl 256 976 0 0 37 2 35 37 0 8 0 bufpl 256 15184 0 8215 436 0 436 436 0 8 0 anonpl 16 772635 0 764963 252 204 48 56 0 125 10 amapchunkpl 152 42137 0 42047 91 82 9 11 0 158 4 amappl16 192 42117 0 41715 380 347 33 33 0 8 12 amappl15 184 3259 0 3256 1 0 1 1 0 8 0 amappl14 176 7 0 5 3 2 1 1 0 8 0 amappl13 168 21 0 18 1 0 1 1 0 8 0 amappl12 160 18 0 17 1 0 1 1 0 8 0 amappl11 152 3495 0 3486 1 0 1 1 0 8 0 amappl10 144 64 0 62 2 1 1 1 0 8 0 amappl9 136 3657 0 3655 1 0 1 1 0 8 0 amappl8 128 242 0 190 2 0 2 2 0 8 0 amappl7 120 35 0 28 1 0 1 1 0 8 0 amappl6 112 53 0 44 1 0 1 1 0 8 0 amappl5 104 3421 0 3408 1 0 1 1 0 8 0 amappl4 96 316 0 295 2 1 1 2 0 8 0 amappl3 88 441 0 436 1 0 1 1 0 8 0 amappl2 80 66872 0 66818 2 0 2 2 0 8 0 amappl1 72 151475 0 151051 23 13 10 19 0 8 0 amappl 72 21308 0 21273 1 0 1 1 0 75 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 dma64 64 259 0 259 1 1 0 1 0 8 0 dma32 32 7 0 7 1 1 0 1 0 8 0 dma16 16 17 0 17 1 1 0 1 0 8 0 aobjpl 64 144 0 15 3 0 3 3 0 8 0 uaddrrnd 24 6759 0 6745 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 6759 0 6745 1 0 1 1 0 8 0 vmmpekpl 168 59796 0 59773 2 0 2 2 0 8 0 vmmpepl 168 727985 0 726598 277 206 71 75 0 357 5 vmsppl 360 6758 0 6745 2 0 2 2 0 8 0 pdppl 4096 13525 0 13490 6 1 5 6 0 8 0 pvpl 32 1943673 0 1932909 443 315 128 142 0 265 37 pmappl 224 6758 0 6745 1 0 1 1 0 8 0 extentpl 40 39 0 25 1 0 1 1 0 8 0 phpool 112 713 0 70 20 0 20 20 0 8 0