panic: Data modified on freelist: word 4 of object 0xffff8000011ec540 size 0x30 previous type free (0x0 != 0xdeadbeef) Stopped at db_enter+0x25: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND *307414 53958 0 0x2 0 0 syz-executor db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff830155fa) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(30,7f,9) at malloc+0xd7c sys/kern/kern_malloc.c:349 dopselect(ffff80002a4571c0,35,750547297100,0,0,ffff80002a4e9d18,65901f4021463528,ffff80002a4571c0) at dopselect+0xe8 sys/kern/sys_generic.c:618 sys_pselect(ffff80002a4571c0,ffff80002a4e9e60,ffff80002a4e9db0) at sys_pselect+0x263 sys/kern/sys_generic.c:592 syscall(ffff80002a4e9e60) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7505472970b0, count: 8 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: Data modified on freelist: word 4 of object 0xffff8000011ec540 size 0x30 previous type free (0x0 != 0xdeadbeef) ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff830155fa) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(30,7f,9) at malloc+0xd7c sys/kern/kern_malloc.c:349 dopselect(ffff80002a4571c0,35,750547297100,0,0,ffff80002a4e9d18,65901f4021463528,ffff80002a4571c0) at dopselect+0xe8 sys/kern/sys_generic.c:618 sys_pselect(ffff80002a4571c0,ffff80002a4e9e60,ffff80002a4e9db0) at sys_pselect+0x263 sys/kern/sys_generic.c:592 syscall(ffff80002a4e9e60) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7505472970b0, count: -7 ddb> show registers rdi 0 rsi 0x1 rbp 0xffff80002a4e9840 rbx 0xffff8000011ec540 rdx 0 rcx 0 rax 0xffff80002a4571c0 r8 0x101010101010101 r9 0x8080808080808080 r10 0xbea5c65f3c263211 r11 0x8584043adf22e179 r12 0 r13 0xffffffff835c0050 bucket+0x1b0 r14 0 r15 0x1 rip 0xffffffff81301ee5 db_enter+0x25 cs 0x8 rflags 0x246 rsp 0xffff80002a4e9830 ss 0x10 db_enter+0x25: addq $0x8,%rsp ddb> show proc PROC (syz-executor) tid=307414 pid=53958 tcnt=1 stat=onproc flags process=2 proc=0 runpri=50, usrpri=50, slppri=24, nice=20 wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0 forw=0xffffffffffffffff, list=0xffff80002a4576d0,0xffff80003761ca50 process=0xffff8000ffff8010 user=0xffff80002a4e4000, vmspace=0xfffffd807ec936b8 estcpu=0, cpticks=2, pctcpu=0.1, user=0, sys=8, intr=0 ddb> ps PID TID PPID UID S FLAGS WAIT COMMAND 64981 477536 62646 0 2 0 syz-executor 64981 467188 62646 0 3 0x4000080 fsleep syz-executor 59026 7288 32812 0 2 0 syz-executor 59026 22129 32812 0 3 0x4000080 fsleep syz-executor 98826 163280 94186 0 2 0 syz-executor 98826 428066 94186 0 3 0x4000080 fsleep syz-executor 98826 432425 94186 0 3 0x4000080 fsleep syz-executor 74731 462605 56229 0 2 0x10 syz-executor 74731 143629 56229 0 3 0x4000090 fsleep syz-executor 74731 425385 56229 0 3 0x4000090 fsleep syz-executor 43246 230982 26508 0 2 0x1 syz-executor 43246 371834 26508 0 3 0x4000080 fsleep syz-executor 43246 267501 26508 0 3 0x4000080 fsleep syz-executor 46863 366620 84620 0 2 0 syz-executor 46863 324899 84620 0 3 0x4000080 fsleep syz-executor 46863 427589 84620 0 3 0x4000080 fsleep syz-executor 62646 23295 53958 0 3 0x82 nanoslp syz-executor 26508 505130 53958 0 3 0x82 nanoslp syz-executor 56229 232166 53958 0 3 0x82 nanoslp syz-executor 94186 85300 53958 0 3 0x82 nanoslp syz-executor 32812 120104 53958 0 3 0x82 nanoslp syz-executor 82045 510507 53958 0 3 0x2 biowait syz-executor 84620 328640 53958 0 3 0x82 nanoslp syz-executor 16151 493670 53958 0 3 0x2 biowait syz-executor 97639 90011 0 0 3 0x14200 bored sosplice *53958 307414 94794 0 7 0x2 syz-executor 94794 148850 78563 0 3 0x10008a sigsusp ksh 78563 226563 18109 0 3 0x98 kqread sshd-session 18109 91190 77697 0 3 0x92 kqread sshd-session 60315 403240 1 0 3 0x100083 ttyin getty 77697 365403 1 0 3 0x88 kqread sshd 78421 469062 18053 73 3 0x1100090 kqread syslogd 18053 113564 1 0 3 0x100082 sbwait syslogd 8148 309749 1 0 3 0x100080 kqread resolvd 66449 432057 40679 77 3 0x100092 kqread dhcpleased 26671 84345 40679 77 3 0x100092 kqread dhcpleased 40679 413588 1 0 3 0x80 kqread dhcpleased 78311 428675 0 0 3 0x14200 bored smr 85997 147721 0 0 2 0x14200 zerothread 31720 77157 0 0 3 0x14200 aiodoned aiodoned 86986 78815 0 0 3 0x14200 syncer update 85648 357612 0 0 3 0x14200 cleaner cleaner 8137 122392 0 0 3 0x14200 reaper reaper 55770 65883 0 0 3 0x14200 pgdaemon pagedaemon 53906 389086 0 0 3 0x14200 bored viomb 3535 255711 0 0 3 0x40014200 acpi0 acpi0 32326 67184 0 0 3 0x14200 bored softnet3 62981 55161 0 0 3 0x14200 bored softnet2 73063 328521 0 0 3 0x14200 bored softnet1 89227 230469 0 0 3 0x14200 bored softnet0 4811 512874 0 0 3 0x14200 bored systqmp 18862 437310 0 0 3 0x14200 bored systq 6437 450841 0 0 3 0x40014200 tmoslp softclock 64926 36591 0 0 3 0x40014200 idle0 1 244010 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 10178 10029K 10350K 166960K 11528 0 pcb 17 12K 12K 166960K 49 0 rtable 200 6K 7K 166960K 634 0 pf 34 13K 14K 166960K 54 0 ifaddr 40 6K 7K 166960K 81 0 ifgroup 54 2K 2K 166960K 91 0 sysctl 2 0K 0K 166960K 2 0 counters 31 17K 17K 166960K 40 0 ioctlops 0 0K 4K 166960K 51 0 iov 0 0K 18K 166960K 17 0 mount 1 1K 1K 166960K 1 0 log 0 0K 0K 166960K 4 0 vnodes 1428 90K 90K 166960K 1675 0 UFS quota 1 32K 32K 166960K 1 0 UFS mount 5 36K 36K 166960K 5 0 shm 2 1K 9K 166960K 11 0 VM map 2 1K 1K 166960K 2 0 sem 10 0K 0K 166960K 14 0 dirhash 12 2K 2K 166960K 12 0 ACPI 1697 195K 286K 166960K 12548 0 file desc 16 57K 97K 166960K 436 0 sigio 0 0K 0K 166960K 11 0 proc 58 59K 124K 166960K 707 0 subproc 104 6K 6K 166960K 208 0 NFS srvsock 1 0K 0K 166960K 1 0 NFS daemon 1 16K 16K 166960K 1 0 ip_moptions 0 0K 0K 166960K 16 0 in_multi 85 6K 7K 166960K 190 0 ether_multi 1 0K 0K 166960K 1 0 ISOFS mount 1 32K 32K 166960K 1 0 MSDOSFS mount 1 16K 16K 166960K 1 0 ttys 55 254K 254K 166960K 55 0 exec 0 0K 1K 166960K 536 0 tdb 3 0K 0K 166960K 3 0 VM swap 8 62K 64K 166960K 10 0 UVM amap 210 72K 91K 166960K 4955 0 UVM aobj 72 3K 3K 166960K 77 0 pinsyscall 37 74K 106K 166960K 1657 0 memdesc 1 4K 4K 166960K 1 0 crypto data 1 1K 1K 166960K 1 0 ip6_options 0 0K 0K 166960K 10 0 NDP 12 0K 2K 166960K 53 0 temp 43 6808K 6872K 166960K 15037 0 kqueue 15 24K 28K 166960K 45 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 67 0 63 1 0 1 1 0 8 0 rtentry 112 210 0 120 4 0 4 4 0 8 0 unpcb 144 292 0 273 6 5 1 6 0 8 0 syncache 336 10 0 10 1 1 0 1 0 8 0 tcpqe 32 2 0 2 1 1 0 1 0 8 0 tcpcb 808 144 0 137 8 7 1 8 0 8 0 arp 88 37 0 20 1 0 1 1 0 8 0 ipq 40 1 0 1 1 1 0 1 0 8 0 ipqe 40 2 0 2 1 1 0 1 0 8 0 inpcb 336 345 0 335 7 5 2 7 0 8 0 nd6 104 51 0 29 1 0 1 1 0 8 0 kcovpl 48 16 0 8 1 0 1 1 0 8 0 pfstscr 40 1 0 1 1 1 0 1 0 8 0 pfstitem 24 2 0 0 1 0 1 1 0 8 0 pfstkey 128 4 0 2 1 0 1 1 0 8 0 pfstate 344 2 0 1 1 0 1 1 0 8 0 pfrule 1344 6 0 5 1 0 1 1 0 8 0 art_heap8 4096 1 0 0 1 0 1 1 0 8 0 art_heap4 256 815 0 444 29 0 29 29 0 8 1 art_table 32 816 0 444 4 0 4 4 0 8 0 art_node 16 208 0 128 1 0 1 1 0 8 0 sysvmsgpl 40 1 0 1 1 1 0 1 0 8 0 semapl 112 9 0 1 1 0 1 1 0 8 0 shmpl 112 74 0 5 2 0 2 2 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino2pl 256 1891 0 383 95 0 95 95 0 8 0 ffsino 240 1891 0 383 90 0 90 90 0 8 0 nchpl 144 2341 0 654 63 0 63 63 0 8 0 uvmvnodes 80 2244 0 0 46 0 46 46 0 8 0 vnodes 216 2244 0 0 125 0 125 125 0 8 0 namei 1024 8328 0 8327 3 2 1 2 0 8 0 kstatmem 264 42 0 18 2 0 2 2 0 8 0 scxspl 216 10961 0 10959 9 1 8 8 1 8 7 plimitpl 152 56 0 39 1 0 1 1 0 8 0 sigapl 424 698 0 653 7 1 6 7 0 8 0 futexpl 64 3123 0 3113 1 0 1 1 0 8 0 knotepl 120 9330 0 9282 10 8 2 10 0 8 0 kqueuepl 184 60 0 45 1 0 1 1 0 8 0 pipepl 288 145 0 118 3 0 3 3 0 8 0 fdescpl 432 681 0 653 5 1 4 5 0 8 0 filepl 120 3146 0 2896 15 7 8 15 0 8 0 lockfpl 104 86 0 84 1 0 1 1 0 8 0 lockfspl 48 35 0 33 1 0 1 1 0 8 0 sessionpl 144 29 0 21 1 0 1 1 0 8 0 pgrppl 48 45 0 29 1 0 1 1 0 8 0 ucredpl 104 217 0 205 1 0 1 1 0 8 0 zombiepl 144 661 0 661 2 1 1 1 0 8 1 processpl 1096 698 0 653 4 0 4 4 0 8 0 procpl 648 996 0 941 6 0 6 6 0 8 0 sosppl 168 4 0 4 1 1 0 1 0 8 0 sockpl 504 706 0 673 25 18 7 23 0 8 1 mcl64k 65536 78 0 78 1 1 0 1 0 8 0 mcl8k 8192 13 0 13 1 1 0 1 0 8 0 mcl4k 4096 3 0 3 1 1 0 1 0 8 0 mcl2k 2048 5511 0 5410 26 13 13 26 0 8 0 mtagpl 96 6 0 6 1 0 1 1 0 8 1 mbufpl 256 9010 0 8797 16 2 14 16 0 8 0 bufpl 280 5120 0 92 360 0 360 360 0 8 0 anonpl 24 202462 0 199227 49 4 45 49 0 187 21 amapchunkpl 152 16443 0 16004 35 15 20 35 0 158 0 amappl16 200 5698 0 5676 19 5 14 14 0 8 11 amappl15 192 12 0 12 1 1 0 1 0 8 0 amappl14 184 128 0 118 1 0 1 1 0 8 0 amappl13 176 31 0 30 1 0 1 1 0 8 0 amappl12 168 1420 0 1392 3 1 2 3 0 8 0 amappl11 160 59 0 49 1 0 1 1 0 8 0 amappl10 152 14 0 14 1 1 0 1 0 8 0 amappl9 144 155 0 155 1 1 0 1 0 8 0 amappl8 136 23 0 22 1 0 1 1 0 8 0 amappl7 128 111 0 101 1 0 1 1 0 8 0 amappl6 120 243 0 242 1 0 1 1 0 8 0 amappl5 112 162 0 154 1 0 1 1 0 8 0 amappl4 104 313 0 295 1 0 1 1 0 8 0 amappl3 96 2959 0 2875 3 0 3 3 0 8 0 amappl2 88 910 0 840 2 0 2 2 0 8 0 amappl1 80 8796 0 8258 15 3 12 15 0 8 0 amappl 88 4547 0 4391 5 0 5 5 0 92 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 dma512 512 1 0 1 1 1 0 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 8 0 8 1 1 0 1 0 8 0 dma16 16 18 0 17 1 0 1 1 0 8 0 aobjpl 72 76 0 5 2 0 2 2 0 8 0 uaddrrnd 24 681 0 653 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 681 0 653 1 0 1 1 0 8 0 vmmpekpl 168 7248 0 7189 3 0 3 3 0 8 0 vmmpepl 168 51632 0 49928 90 1 89 90 0 357 7 vmsppl 344 680 0 653 4 1 3 4 0 8 0 rwobjpl 24 21910 0 18752 21 0 21 21 0 8 1 pdppl 4096 1368 0 1306 110 44 66 82 0 8 4 pvpl 32 408888 0 398839 214 123 91 214 0 265 2 pmappl 216 680 0 653 3 1 2 3 0 8 0 extentpl 40 56 0 38 1 0 1 1 0 8 0 phpool 112 424 0 98 11 0 11 11 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:437 panic(ffffffff830155fa) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(30,7f,9) at malloc+0xd7c sys/kern/kern_malloc.c:349 dopselect(ffff80002a4571c0,35,750547297100,0,0,ffff80002a4e9d18,65901f4021463528,ffff80002a4571c0) at dopselect+0xe8 sys/kern/sys_generic.c:618 sys_pselect(ffff80002a4571c0,ffff80002a4e9e60,ffff80002a4e9db0) at sys_pselect+0x263 sys/kern/sys_generic.c:592 syscall(ffff80002a4e9e60) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7505472970b0, count: -7 ddb> machine ddbcpu 1 No such command ddb> trace db_enter() at db_enter+0x25 sys/arch/amd64/amd64/db_interface.c:437 panic(ffffffff830155fa) at panic+0x1cf sys/kern/subr_prf.c:198 malloc(30,7f,9) at malloc+0xd7c sys/kern/kern_malloc.c:349 dopselect(ffff80002a4571c0,35,750547297100,0,0,ffff80002a4e9d18,65901f4021463528,ffff80002a4571c0) at dopselect+0xe8 sys/kern/sys_generic.c:618 sys_pselect(ffff80002a4571c0,ffff80002a4e9e60,ffff80002a4e9db0) at sys_pselect+0x263 sys/kern/sys_generic.c:592 syscall(ffff80002a4e9e60) at syscall+0x97e sys/arch/amd64/amd64/trap.c:577 Xsyscall() at Xsyscall+0x128 end of kernel end trace frame: 0x7505472970b0, count: -7