panic: Data modified on freelist: word 4 of object 0xffff800000b95100 size 0xc0 previous type free (0xdeafbe00 != 0xdeafbead) Stopped at db_enter+0x18: addq $0x8,%rsp TID PID UID PRFLAGS PFLAGS CPU COMMAND 410391 2061 0 0 0 0 syz-executor.1 *255579 2061 0 0 0x4000000 1K syz-executor.1 db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 malloc(c0,5,9) at malloc+0xa23 sys/kern/kern_malloc.c:331 rtm_report(fffffd806f537000,4,35d33fc7,0) at rtm_report+0x2d9 sys/net/rtsock.c:654 route_output(fffffd807de7d000,fffffd80719a0c58,0,0) at route_output+0x6b9 sys/net/rtsock.c:824 route_usrreq(fffffd80719a0c58,9,fffffd807de7d000,0,0,ffff800020aceef0) at route_usrreq+0x363 sys/net/rtsock.c:275 sosend(fffffd80719a0c58,0,ffff800023b89010,0,0,0) at sosend+0x645 sys/kern/uipc_socket.c:524 sendit(ffff800020aceef0,5,ffff800023b890f0,0,ffff800023b891d0) at sendit+0x52b sys/kern/uipc_syscalls.c:662 sys_sendto(ffff800020aceef0,ffff800023b89188,ffff800023b891d0) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 syscall(ffff800023b89250) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800023b89250) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffd8,0,6,9bbd1766010) at Xsyscall+0x128 end of kernel end trace frame: 0x9bde8b6da80, count: 4 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 Data modified on freelist: word 4 of object 0xffff800000b95100 size 0xc0 previous type free (0xdeafbe00 != 0xdeafbead) ddb{1}> trace db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398 panic() at panic+0x15c sys/kern/subr_prf.c:207 malloc(c0,5,9) at malloc+0xa23 sys/kern/kern_malloc.c:331 rtm_report(fffffd806f537000,4,35d33fc7,0) at rtm_report+0x2d9 sys/net/rtsock.c:654 route_output(fffffd807de7d000,fffffd80719a0c58,0,0) at route_output+0x6b9 sys/net/rtsock.c:824 route_usrreq(fffffd80719a0c58,9,fffffd807de7d000,0,0,ffff800020aceef0) at route_usrreq+0x363 sys/net/rtsock.c:275 sosend(fffffd80719a0c58,0,ffff800023b89010,0,0,0) at sosend+0x645 sys/kern/uipc_socket.c:524 sendit(ffff800020aceef0,5,ffff800023b890f0,0,ffff800023b891d0) at sendit+0x52b sys/kern/uipc_syscalls.c:662 sys_sendto(ffff800020aceef0,ffff800023b89188,ffff800023b891d0) at sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 syscall(ffff800023b89250) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] syscall(ffff800023b89250) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 Xsyscall(6,0,ffffffffffffffd8,0,6,9bbd1766010) at Xsyscall+0x128 end of kernel end trace frame: 0x9bde8b6da80, count: -11 ddb{1}> show registers rdi 0xffffffff820cd6c7 db_enter+0x17 rsi 0x77a3 __ALIGN_SIZE+0x67a3 rbp 0xffff800023b88a50 rbx 0xffff800023b88b00 rdx 0x77a4 __ALIGN_SIZE+0x67a4 rcx 0xffff800020d5e000 rax 0xffff800020d5e000 r8 0xffffffff814de02f kprintf+0x16f r9 0x1 r10 0x25 r11 0x1b529f9b86730333 r12 0x3000000008 r13 0xffff800023b88a60 r14 0x100 r15 0x1 rip 0xffffffff820cd6c8 db_enter+0x18 cs 0x8 rflags 0x246 rsp 0xffff800023b88a40 ss 0x10 db_enter+0x18: addq $0x8,%rsp ddb{1}> show proc PROC (syz-executor.1) pid=255579 stat=onproc flags process=0 proc=4000000 pri=86, usrpri=86, nice=20 forw=0xffffffffffffffff, list=0xffff800020acea00,0xffffffff82642078 process=0xffff800020add180 user=0xffff800023b84000, vmspace=0xfffffd807f00a730 estcpu=36, cpticks=3, pctcpu=0.0 user=0, sys=3, intr=0 ddb{1}> ps PID TID PPID UID S FLAGS WAIT COMMAND 2061 410391 55175 0 7 0 syz-executor.1 * 2061 255579 55175 0 7 0x4000000 syz-executor.1 55175 391911 61246 0 3 0x82 nanosleep syz-executor.1 50413 483187 1 0 3 0x100083 ttyin getty 1832 285097 61246 0 3 0x82 nanosleep syz-executor.0 68104 366307 0 0 3 0x14200 acct acct 83606 5289 0 0 3 0x14200 bored sosplice 61246 39127 18192 0 3 0x82 thrsleep syz-fuzzer 61246 189552 18192 0 3 0x4000082 nanosleep syz-fuzzer 61246 149346 18192 0 3 0x4000082 thrsleep syz-fuzzer 61246 84160 18192 0 3 0x4000082 thrsleep syz-fuzzer 61246 192363 18192 0 3 0x4000082 thrsleep syz-fuzzer 61246 424304 18192 0 3 0x4000082 kqread syz-fuzzer 61246 357164 18192 0 3 0x4000082 nanosleep syz-fuzzer 61246 399612 18192 0 3 0x4000082 thrsleep syz-fuzzer 61246 470313 18192 0 3 0x4000082 thrsleep syz-fuzzer 61246 328931 18192 0 3 0x4000082 thrsleep syz-fuzzer 18192 164461 30051 0 3 0x10008a pause ksh 30051 226659 67041 0 3 0x92 select sshd 67041 429075 1 0 3 0x80 select sshd 54266 429953 12464 74 3 0x100092 bpf pflogd 12464 390036 1 0 3 0x80 netio pflogd 80171 201773 59324 73 3 0x100090 kqread syslogd 59324 300209 1 0 3 0x100082 netio syslogd 67398 446962 1 77 3 0x100090 poll dhclient 65137 457055 1 0 3 0x80 poll dhclient 99878 435862 0 0 3 0x14200 pgzero zerothread 99410 386487 0 0 3 0x14200 aiodoned aiodoned 79835 494477 0 0 3 0x14200 syncer update 48666 517603 0 0 3 0x14200 cleaner cleaner 50389 486461 0 0 3 0x14200 reaper reaper 25071 44035 0 0 3 0x14200 pgdaemon pagedaemon 28164 32804 0 0 3 0x14200 bored crynlk 52875 450869 0 0 3 0x14200 bored crypto 13516 185176 0 0 3 0x40014200 acpi0 acpi0 42017 477246 0 0 3 0x40014200 idle1 5692 276527 0 0 3 0x14200 bored softnet 30199 202797 0 0 3 0x14200 bored systqmp 89472 220424 0 0 3 0x14200 bored systq 73616 413006 0 0 3 0x40014200 bored softclock 42664 239210 0 0 3 0x40014200 idle0 40680 360677 0 0 3 0x14200 bored smr 1 189979 0 0 3 0x82 wait init 0 0 -1 0 3 0x10200 scheduler swapper ddb{1}> show all locks CPU 1: exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff825049d0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 malloc+0x23b sys/kern/kern_malloc.c:209 #4 rtm_report+0x2d9 sys/net/rtsock.c:654 #5 route_output+0x6b9 sys/net/rtsock.c:824 #6 route_usrreq+0x363 sys/net/rtsock.c:275 #7 sosend+0x645 sys/kern/uipc_socket.c:524 #8 sendit+0x52b sys/kern/uipc_syscalls.c:662 #9 sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 #10 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] #10 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 #11 Xsyscall+0x128 Process 2061 (syz-executor.1) thread 0xffff800020aceef0 (255579) exclusive kernel_lock &kernel_lock r = 0 (0xffffffff82622388) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 solock+0x66 sys/kern/uipc_socket2.c:292 #2 sosend+0x51b sys/kern/uipc_socket.c:512 #3 sendit+0x52b sys/kern/uipc_syscalls.c:662 #4 sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 #5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] #5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 #6 Xsyscall+0x128 exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff825049d0) #0 witness_lock+0x52e sys/kern/subr_witness.c:1163 #1 mtx_enter_try+0x102 #2 mtx_enter+0x4b sys/kern/kern_lock.c:266 #3 malloc+0x23b sys/kern/kern_malloc.c:209 #4 rtm_report+0x2d9 sys/net/rtsock.c:654 #5 route_output+0x6b9 sys/net/rtsock.c:824 #6 route_usrreq+0x363 sys/net/rtsock.c:275 #7 sosend+0x645 sys/kern/uipc_socket.c:524 #8 sendit+0x52b sys/kern/uipc_syscalls.c:662 #9 sys_sendto+0x80 sys/kern/uipc_syscalls.c:527 #10 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:92 [inline] #10 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:555 #11 Xsyscall+0x128 ddb{1}> show malloc Type InUse MemUse HighUse Limit Requests Type Lim Kern Lim devbuf 9628 6475K 8895K 78643K 52377 0 0 pcb 13 10K 12K 78643K 2270 0 0 rtable 128 14K 16K 78643K 11038 0 0 ifaddr 107 27K 29K 78643K 1898 0 0 counters 39 33K 33K 78643K 39 0 0 ioctlops 0 0K 4K 78643K 1994 0 0 iov 0 0K 32K 78643K 2267 0 0 mount 1 1K 1K 78643K 1 0 0 vnodes 1222 77K 78K 78643K 14201 0 0 UFS quota 1 32K 32K 78643K 1 0 0 UFS mount 5 36K 36K 78643K 5 0 0 shm 2 1K 9K 78643K 163 0 0 VM map 80 40K 40K 78643K 114 0 0 sem 12 0K 1K 78643K 1988 0 0 dirhash 12 2K 2K 78643K 12 0 0 ACPI 1808 196K 290K 78643K 12765 0 0 file desc 5 13K 25K 78643K 9635 0 0 sigio 0 0K 0K 78643K 101 0 0 proc 62 63K 95K 78643K 4103 0 0 subproc 32 2K 2K 78643K 1216 0 0 NFS srvsock 1 0K 0K 78643K 1 0 0 NFS daemon 1 16K 16K 78643K 1 0 0 ip_moptions 2 0K 1K 78643K 6047 0 0 in_multi 38 2K 3K 78643K 2349 0 0 ether_multi 1 0K 0K 78643K 120 0 0 mrt 1 0K 0K 78643K 61 0 0 ISOFS mount 1 32K 32K 78643K 1 0 0 MSDOSFS mount 1 16K 16K 78643K 1 0 0 ttys 102 450K 450K 78643K 102 0 0 exec 0 0K 1K 78643K 2109 0 0 pfkey data 0 0K 4K 78643K 8 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 261 725K 735K 78643K 35340 0 0 UVM aobj 130 4K 4K 78643K 142 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 2317 0 0 NDP 25 0K 1K 78643K 604 0 0 temp 264 3561K 4201K 78643K 341669 0 0 kqueue 0 0K 0K 78643K 76 0 0 SYN cache 2 16K 16K 78643K 2 0 0 ddb{1}> show all pools Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle arp 64 215 0 208 1 0 1 1 0 8 0 plcache 128 20 0 0 1 0 1 1 0 8 0 rtpcb 80 4241 0 4238 1 0 1 1 0 8 0 rtentry 112 1139 0 1094 2 0 2 2 0 8 0 unpcb 120 6326 0 6311 3 2 1 2 0 8 0 syncache 264 43 0 43 17 17 0 1 0 8 0 sackhl 24 1 0 1 1 1 0 1 0 8 0 tcpqe 32 21 0 21 9 9 0 1 0 8 0 tcpcb 544 4772 0 4766 24 22 2 13 0 8 1 inpcb 280 19774 0 19761 19 17 2 9 0 8 1 rttmr 72 16 0 16 2 2 0 1 0 8 0 ip6q 72 9 0 9 7 7 0 1 0 8 0 ip6af 40 19 0 19 5 5 0 1 0 8 0 nd6 48 169 0 166 6 5 1 1 0 8 0 pkpcb 40 100 0 100 21 20 1 1 0 8 1 swfcl 56 10 0 0 1 0 1 1 0 8 0 ppxss 1128 259 0 259 22 21 1 1 0 8 1 pffrag 232 269 0 269 22 21 1 1 0 482 1 pffrnode 88 269 0 269 22 21 1 1 0 8 1 pffrent 40 7522 0 7522 21 20 1 1 0 8 1 pfosfp 40 846 0 423 5 0 5 5 0 8 0 pfosfpen 112 1428 0 714 21 0 21 21 0 8 0 pfstitem 24 735 0 670 1 0 1 1 0 8 0 pfstkey 112 737 0 672 3 1 2 3 0 8 0 pfstate 328 737 0 672 9 3 6 7 0 8 0 pfrule 1360 21 0 16 2 1 1 2 0 8 0 art_heap8 4096 21 0 20 19 18 1 3 0 8 0 art_heap4 256 4747 0 4496 61 43 18 19 0 8 0 art_table 32 4768 0 4516 9 6 3 3 0 8 0 art_node 16 1127 0 1085 1 0 1 1 0 8 0 sysvmsgpl 40 24 0 17 1 0 1 1 0 8 0 semupl 112 2 0 2 1 1 0 1 0 8 0 semapl 112 1984 0 1974 1 0 1 1 0 8 0 shmpl 112 140 0 12 4 0 4 4 0 8 0 dirhash 1024 17 0 0 3 0 3 3 0 8 0 dino1pl 128 15737 0 14269 49 1 48 48 0 8 0 ffsino 272 15737 0 14269 99 0 99 99 0 8 0 nchpl 144 29748 0 29287 61 41 20 61 0 8 0 uvmvnodes 72 7769 0 0 142 0 142 142 0 8 0 vnodes 208 7769 0 0 409 0 409 409 0 8 0 namei 1024 111450 0 111450 1 0 1 1 0 8 1 percpumem 16 30 0 0 1 0 1 1 0 8 0 vcpupl 1984 79 0 1 10 0 10 10 0 8 0 vmpool 552 112 0 34 7 1 6 6 0 8 0 scsiplug 64 14 0 14 9 9 0 1 0 8 0 scxspl 192 103849 0 103849 61 58 3 7 0 8 3 plimitpl 152 852 0 844 1 0 1 1 0 8 0 sigapl 432 9631 0 9616 4 2 2 3 0 8 0 futexpl 56 229938 0 229938 1 0 1 1 0 8 1 knotepl 112 2866 0 2847 8 7 1 2 0 8 0 kqueuepl 104 2652 0 2650 4 3 1 4 0 8 0 pipepl 112 7434 0 7415 22 20 2 2 0 8 1 fdescpl 488 9632 0 9616 3 0 3 3 0 8 0 filepl 152 92547 0 92444 54 47 7 13 0 8 2 lockfpl 104 3409 0 3408 1 0 1 1 0 8 0 lockfspl 48 1156 0 1155 1 0 1 1 0 8 0 sessionpl 112 90 0 79 1 0 1 1 0 8 0 pgrppl 48 189 0 178 1 0 1 1 0 8 0 ucredpl 96 9303 0 9294 1 0 1 1 0 8 0 zombiepl 144 9622 0 9621 2 1 1 1 0 8 0 processpl 896 9655 0 9621 4 0 4 4 0 8 0 procpl 632 30941 0 30897 5 0 5 5 0 8 0 srpgc 64 110 0 110 29 28 1 1 0 8 1 sosppl 128 156 0 156 27 27 0 1 0 8 0 sockpl 384 30610 0 30582 58 53 5 14 0 8 2 mcl64k 65536 354 0 0 39 15 24 34 0 8 0 mcl16k 16384 28 0 0 4 1 3 3 0 8 0 mcl12k 12288 33 0 0 2 0 2 2 0 8 0 mcl9k 9216 31 0 0 2 0 2 2 0 8 0 mcl8k 8192 17 0 0 3 0 3 3 0 8 0 mcl4k 4096 41 0 0 4 1 3 3 0 8 0 mcl2k2 2112 10 0 0 1 0 1 1 0 8 0 mcl2k 2048 186 0 0 20 5 15 20 0 8 0 mtagpl 80 76 0 0 1 0 1 1 0 8 0 mbufpl 256 1046 0 0 36 0 36 36 0 8 0 bufpl 256 41255 0 33483 486 0 486 486 0 8 0 anonpl 16 1234823 0 1214610 311 221 90 104 0 124 0 amapchunkpl 152 73973 0 73789 164 149 15 22 0 158 4 amappl16 192 52861 0 51592 333 265 68 76 0 8 4 amappl15 184 2848 0 2848 11 11 0 1 0 8 0 amappl14 176 1734 0 1728 1 0 1 1 0 8 0 amappl13 168 1043 0 1042 7 6 1 1 0 8 0 amappl12 160 923 0 919 2 1 1 1 0 8 0 amappl11 152 531 0 516 1 0 1 1 0 8 0 amappl10 144 1352 0 1345 1 0 1 1 0 8 0 amappl9 136 3009 0 3001 1 0 1 1 0 8 0 amappl8 128 2612 0 2549 4 1 3 3 0 8 0 amappl7 120 1564 0 1554 1 0 1 1 0 8 0 amappl6 112 419 0 397 1 0 1 1 0 8 0 amappl5 104 1643 0 1630 1 0 1 1 0 8 0 amappl4 96 10232 0 10199 1 0 1 1 0 8 0 amappl3 88 2073 0 2060 1 0 1 1 0 8 0 amappl2 80 73386 0 73294 4 1 3 3 0 8 0 amappl1 72 229928 0 229493 25 14 11 20 0 8 0 amappl 80 32506 0 32417 3 0 3 3 0 84 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 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 17 0 17 1 1 0 1 0 8 0 aobjpl 64 141 0 12 3 0 3 3 0 8 0 uaddrrnd 24 9744 0 9616 1 0 1 1 0 8 0 uaddrbest 32 2 0 0 1 0 1 1 0 8 0 uaddr 24 9744 0 9616 1 0 1 1 0 8 0 vmmpekpl 168 78826 0 78773 5 2 3 3 0 8 0 vmmpepl 168 1256400 0 1253732 394 233 161 165 0 357 38 vmsppl 368 9631 0 9616 2 0 2 2 0 8 0 pdppl 4096 19495 0 19378 18 3 15 16 0 8 0 pvpl 32 3200314 0 3180201 561 375 186 220 0 265 0 pmappl 232 9743 0 9650 7 1 6 6 0 8 0 extentpl 40 41 0 26 1 0 1 1 0 8 0 phpool 112 823 0 111 21 0 21 21 0 8 0