panic: Data modified on freelist: word 4 of object 0xffff8000009d7000 size 0xe10 previous type free (0x0 != 0xdeaf4152)
Stopped at db_enter+0x18: addq $0x8,%rsp
TID PID UID PRFLAGS PFLAGS CPU COMMAND
* 84685 83679 0 0x2 0 0K syz-executor.0
419208 63957 0 0x2 0x4000000 1 syz-fuzzer
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821f5e43) at panic+0x15c sys/kern/subr_prf.c:207
malloc(e10,27,9) at malloc+0xa23 sys/kern/kern_malloc.c:331
fdcopy(ffff800020ec9b00) at fdcopy+0x1fa sys/kern/kern_descrip.c:1135
process_new(ffff800020e929d8,ffff800020ec9b00,1) at process_new+0x12c sys/kern/kern_fork.c:253
fork1(ffff800020e6c758,1,ffffffff81e1e3b0,0,ffff800020f6b130,0) at fork1+0x31b sys/kern/kern_fork.c:377
syscall(ffff800020f6b1b0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020f6b1b0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7fffff1b70, count: 7
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}> set $maxwidth = 0
ddb{0}> show panic
Data modified on freelist: word 4 of object 0xffff8000009d7000 size 0xe10 previous type free (0x0 != 0xdeaf4152)
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821f5e43) at panic+0x15c sys/kern/subr_prf.c:207
malloc(e10,27,9) at malloc+0xa23 sys/kern/kern_malloc.c:331
fdcopy(ffff800020ec9b00) at fdcopy+0x1fa sys/kern/kern_descrip.c:1135
process_new(ffff800020e929d8,ffff800020ec9b00,1) at process_new+0x12c sys/kern/kern_fork.c:253
fork1(ffff800020e6c758,1,ffffffff81e1e3b0,0,ffff800020f6b130,0) at fork1+0x31b sys/kern/kern_fork.c:377
syscall(ffff800020f6b1b0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020f6b1b0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7fffff1b70, count: -8
ddb{0}> show registers
rdi 0
rsi 0x1
rbp 0xffff800020f6add0
rbx 0xffff800020f6ae80
rdx 0x8b
rcx 0x2
rax 0x1
r8 0xffffffff81f3c28f kprintf+0x16f
r9 0x1
r10 0x2
r11 0x590321589b1e6cb7
r12 0x3000000008
r13 0xffff800020f6ade0
r14 0x100
r15 0x1
rip 0xffffffff8149f5a8 db_enter+0x18
cs 0x8
rflags 0x246
rsp 0xffff800020f6adc0
ss 0x10
db_enter+0x18: addq $0x8,%rsp
ddb{0}> show proc
PROC (syz-executor.0) pid=84685 stat=onproc
flags process=2<EXEC,8ORPHAN> proc=0
pri=78, usrpri=78, nice=20
forw=0xffffffffffffffff, list=0xffff800020e6cc38,0xffff800020e93888
process=0xffff800020ec9b00 user=0xffff800020f66000, vmspace=0xfffffd807efffcf0
estcpu=36, cpticks=7, pctcpu=0.24
user=0, sys=2, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
88696 457489 0 0 3 0x14280 nfsidl nfsio
5550 480626 0 0 3 0x14280 nfsidl nfsio
51593 489497 0 0 3 0x14280 nfsidl nfsio
15779 39639 0 0 3 0x14280 nfsidl nfsio
7684 207121 0 0 3 0x14280 nfsidl nfsio
81794 202327 0 0 3 0x14280 nfsidl nfsio
63255 137976 0 0 3 0x14280 nfsidl nfsio
43702 160956 0 0 3 0x14280 nfsidl nfsio
14529 464600 0 0 3 0x14280 nfsidl nfsio
19953 161141 0 0 3 0x14280 nfsidl nfsio
69335 45620 0 0 3 0x14280 nfsidl nfsio
95533 67601 0 0 3 0x14280 nfsidl nfsio
1773 223175 0 0 3 0x14280 nfsidl nfsio
52938 157846 0 0 3 0x14280 nfsidl nfsio
95581 16793 0 0 3 0x14280 nfsidl nfsio
46043 220120 0 0 3 0x14280 nfsidl nfsio
81608 460845 0 0 3 0x14280 nfsidl nfsio
11512 96565 0 0 3 0x14280 nfsidl nfsio
15898 371835 0 0 3 0x14280 nfsidl nfsio
36310 56019 0 0 3 0x14280 nfsidl nfsio
34256 274945 0 0 3 0x14200 bored sosplice
1289 514990 63957 0 3 0x82 piperd syz-executor.1
*83679 84685 63957 0 7 0x2 syz-executor.0
63957 485527 18588 0 3 0x82 kqread syz-fuzzer
63957 447593 18588 0 3 0x4000082 nanosleep syz-fuzzer
63957 421724 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 132969 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 358776 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 319494 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 177625 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 274348 18588 0 3 0x4000082 thrsleep syz-fuzzer
63957 419208 18588 0 7 0x4000002 syz-fuzzer
63957 279351 18588 0 3 0x4000082 thrsleep syz-fuzzer
18588 241951 88017 0 3 0x10008a pause ksh
88017 405284 56050 0 3 0x92 select sshd
21469 478791 1 0 3 0x100083 ttyin getty
56050 197792 1 0 3 0x80 select sshd
62277 197262 41300 74 3 0x100092 bpf pflogd
41300 193707 1 0 3 0x80 netio pflogd
55514 121373 11390 73 3 0x100090 kqread syslogd
11390 392648 1 0 3 0x100082 netio syslogd
25289 365690 1 77 3 0x100090 poll dhclient
59768 47915 1 0 3 0x80 poll dhclient
26728 465666 0 0 3 0x14200 bored smr
27439 41579 0 0 2 0x14200 zerothread
83041 108047 0 0 3 0x14200 aiodoned aiodoned
12502 449573 0 0 3 0x14200 syncer update
88326 72357 0 0 3 0x14200 cleaner cleaner
18917 123567 0 0 3 0x14200 reaper reaper
22758 452364 0 0 3 0x14200 pgdaemon pagedaemon
21750 255139 0 0 3 0x14200 bored crynlk
54265 80914 0 0 3 0x14200 bored crypto
98093 470158 0 0 3 0x40014200 acpi0 acpi0
84643 205664 0 0 3 0x40014200 idle1
27755 301333 0 0 3 0x14200 bored softnet
14390 90602 0 0 3 0x14200 bored systqmp
13142 369477 0 0 3 0x14200 bored systq
73950 176054 0 0 3 0x40014200 bored softclock
16238 204979 0 0 3 0x40014200 idle0
1 13534 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{0}> show all locks
CPU 0:
exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff824a2390)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#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 fdcopy+0x1fa sys/kern/kern_descrip.c:1135
#5 process_new+0x12c sys/kern/kern_fork.c:253
#6 fork1+0x31b sys/kern/kern_fork.c:377
#7 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#7 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#8 Xsyscall+0x128
Process 83679 (syz-executor.0) thread 0xffff800020e6c758 (84685)
exclusive rwlock fdlock r = 0 (0xfffffd807cf85068)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#1 fdcopy+0x131 sys/kern/kern_descrip.c:1111
#2 process_new+0x12c sys/kern/kern_fork.c:253
#3 fork1+0x31b sys/kern/kern_fork.c:377
#4 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#4 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#5 Xsyscall+0x128
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8266d5a0)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#1 syscall+0x400 mi_syscall sys/sys/syscall_mi.h:93 [inline]
#1 syscall+0x400 sys/arch/amd64/amd64/trap.c:570
#2 Xsyscall+0x128
exclusive mutex /syzkaller/managers/multicore/kernel/sys/kern/kern_malloc.c:104 r = 0 (0xffffffff824a2390)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#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 fdcopy+0x1fa sys/kern/kern_descrip.c:1135
#5 process_new+0x12c sys/kern/kern_fork.c:253
#6 fork1+0x31b sys/kern/kern_fork.c:377
#7 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#7 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#8 Xsyscall+0x128
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9527 6419K 7190K 78643K 11980 0
pcb 13 8K 8K 78643K 77 0
rtable 83 2K 3K 78643K 271 0
ifaddr 83 16K 16K 78643K 105 0
counters 43 33K 34K 78643K 47 0
ioctlops 0 0K 4K 78643K 1483 0
iov 0 0K 32K 78643K 77 0
mount 1 1K 1K 78643K 1 0
vnodes 1224 77K 77K 78643K 1582 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 3 0
VM map 2 1K 1K 78643K 2 0
sem 11 1K 1K 78643K 17 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1824 197K 290K 78643K 13058 0
file desc 4 13K 25K 78643K 333 0
sigio 0 0K 0K 78643K 5 0
proc 61 63K 95K 78643K 478 0
subproc 32 2K 2K 78643K 34 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 14 0
in_multi 60 3K 3K 78643K 89 0
ether_multi 1 0K 0K 78643K 10 0
mrt 0 0K 0K 78643K 3 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 49 228K 228K 78643K 49 0
exec 0 0K 1K 78643K 240 0
pagedep 1 8K 8K 78643K 1 0
inodedep 1 32K 32K 78643K 1 0
newblk 1 0K 0K 78643K 1 0
VM swap 7 26K 26K 78643K 7 0
UVM amap 116 22K 39K 78643K 1959 0
UVM aobj 11 2K 3K 78643K 15 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 48 0
NDP 13 0K 0K 78643K 20 0
temp 111 3036K 3100K 78643K 10489 0
kqueue 3 4K 10K 78643K 16 0
SYN cache 2 16K 16K 78643K 2 0
ddb{0}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp 64 7 0 1 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 80 40 0 38 1 0 1 1 0 8 0
rtentry 112 54 0 21 2 0 2 2 0 8 0
unpcb 120 273 0 263 1 0 1 1 0 8 0
syncache 264 4 0 4 1 1 0 1 0 8 0
tcpqe 32 543 0 543 1 1 0 1 0 8 0
tcpcb 544 107 0 103 1 0 1 1 0 8 0
inpcb 280 340 0 333 4 2 2 2 0 8 1
rttmr 72 1 0 1 1 0 1 1 0 8 1
nd6 48 8 0 3 1 0 1 1 0 8 0
pkpcb 40 3 0 3 2 1 1 1 0 8 1
pffrag 232 5 0 5 3 3 0 1 0 482 0
pffrnode 88 5 0 5 3 3 0 1 0 8 0
pffrent 40 139 0 139 3 3 0 1 0 8 0
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 42 0 9 1 0 1 1 0 8 0
pfstkey 112 42 0 9 1 0 1 1 0 8 0
pfstate 328 42 0 9 3 0 3 3 0 8 0
pfrule 1360 21 0 16 2 1 1 2 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 258 0 83 12 1 11 12 0 8 0
art_table 32 259 0 83 2 0 2 2 0 8 0
art_node 16 53 0 26 1 0 1 1 0 8 0
sysvmsgpl 40 10 0 3 1 0 1 1 0 8 0
semupl 112 3 0 3 2 2 0 1 0 8 0
semapl 112 9 0 0 1 0 1 1 0 8 0
shmpl 112 13 0 4 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 1861 0 457 89 0 89 89 0 8 0
ffsino 272 1861 0 457 95 1 94 94 0 8 0
nchpl 144 2607 0 1000 60 0 60 60 0 8 0
uvmvnodes 72 2214 0 0 41 0 41 41 0 8 0
vnodes 208 2214 0 0 117 0 117 117 0 8 0
namei 1024 7174 0 7174 2 1 1 1 0 8 1
percpumem 16 34 0 2 1 0 1 1 0 8 0
vmpool 560 2 0 2 1 0 1 1 0 8 1
scxspl 192 7217 0 7217 10 7 3 7 0 8 3
plimitpl 152 23 0 15 1 0 1 1 0 8 0
sigapl 424 569 0 518 6 0 6 6 0 8 0
futexpl 56 5591 0 5591 1 0 1 1 0 8 1
knotepl 112 78 0 59 1 0 1 1 0 8 0
kqueuepl 144 42 0 40 1 0 1 1 0 8 0
pipelkpl 48 127 0 117 1 0 1 1 0 8 0
pipepl 120 254 0 235 1 0 1 1 0 8 0
fdescpl 496 534 0 518 3 0 3 3 0 8 0
filepl 152 3370 0 3270 7 1 6 6 0 8 2
lockfpl 104 163 0 162 1 0 1 1 0 8 0
lockfspl 48 51 0 50 1 0 1 1 0 8 0
sessionpl 112 18 0 7 1 0 1 1 0 8 0
pgrppl 48 22 0 11 1 0 1 1 0 8 0
ucredpl 96 260 0 251 1 0 1 1 0 8 0
zombiepl 144 518 0 518 2 1 1 1 0 8 1
processpl 984 570 0 518 8 1 7 7 0 8 0
procpl 624 1211 0 1150 6 0 6 6 0 8 1
sosppl 128 5 0 5 2 1 1 1 0 8 1
sockpl 400 661 0 642 7 2 5 5 0 8 3
mcl64k 65536 8 0 0 1 0 1 1 0 8 0
mcl12k 12288 4 0 0 1 0 1 1 0 8 0
mcl9k 9216 1 0 0 1 0 1 1 0 8 0
mcl8k 8192 3 0 0 1 0 1 1 0 8 0
mcl4k 4096 7 0 0 1 0 1 1 0 8 0
mcl2k2 2112 2 0 0 1 0 1 1 0 8 0
mcl2k 2048 233 0 0 29 1 28 29 0 8 0
mtagpl 80 184 0 0 4 0 4 4 0 8 0
mbufpl 256 520 0 0 30 0 30 30 0 8 0
bufpl 280 4174 0 137 289 0 289 289 0 8 0
anonpl 16 63617 0 49072 77 16 61 75 0 124 1
amapchunkpl 152 2829 0 2702 18 5 13 13 0 158 7
amappl16 192 2459 0 1672 52 11 41 52 0 8 0
amappl15 184 69 0 67 1 0 1 1 0 8 0
amappl14 176 22 0 18 1 0 1 1 0 8 0
amappl13 168 262 0 257 1 0 1 1 0 8 0
amappl12 160 8 0 6 2 1 1 1 0 8 0
amappl11 152 57 0 42 1 0 1 1 0 8 0
amappl10 144 29 0 23 1 0 1 1 0 8 0
amappl9 136 377 0 375 1 0 1 1 0 8 0
amappl8 128 355 0 317 2 0 2 2 0 8 0
amappl7 120 117 0 107 1 0 1 1 0 8 0
amappl6 112 26 0 20 1 0 1 1 0 8 0
amappl5 104 451 0 436 1 0 1 1 0 8 0
amappl4 96 716 0 687 1 0 1 1 0 8 0
amappl3 88 112 0 107 1 0 1 1 0 8 0
amappl2 80 3343 0 3282 2 0 2 2 0 8 0
amappl1 72 21107 0 20675 24 14 10 18 0 8 0
amappl 80 1434 0 1394 2 0 2 2 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 18 0 17 1 0 1 1 0 8 0
aobjpl 64 14 0 4 1 0 1 1 0 8 0
uaddrrnd 24 535 0 520 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 535 0 520 1 0 1 1 0 8 0
vmmpekpl 168 7950 0 7917 2 0 2 2 0 8 0
vmmpepl 168 71095 0 69257 119 31 88 108 0 357 0
vmsppl 368 534 0 520 2 0 2 2 0 8 0
pdppl 4096 1078 0 1040 6 0 6 6 0 8 0
pvpl 32 203581 0 185864 184 16 168 182 0 265 22
pmappl 232 534 0 520 2 1 1 2 0 8 0
extentpl 40 53 0 36 1 0 1 1 0 8 0
phpool 112 290 0 9 9 0 9 9 0 8 0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
db_enter() at db_enter+0x18 sys/arch/amd64/amd64/db_interface.c:398
panic(ffffffff821f5e43) at panic+0x15c sys/kern/subr_prf.c:207
malloc(e10,27,9) at malloc+0xa23 sys/kern/kern_malloc.c:331
fdcopy(ffff800020ec9b00) at fdcopy+0x1fa sys/kern/kern_descrip.c:1135
process_new(ffff800020e929d8,ffff800020ec9b00,1) at process_new+0x12c sys/kern/kern_fork.c:253
fork1(ffff800020e6c758,1,ffffffff81e1e3b0,0,ffff800020f6b130,0) at fork1+0x31b sys/kern/kern_fork.c:377
syscall(ffff800020f6b1b0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020f6b1b0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7fffff1b70, count: -8
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffff800020e00ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xc6 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
end of kernel
end trace frame: 0xc0003eec58, count: 12
ddb{1}> trace
x86_ipi_db(ffff800020e00ff0) at x86_ipi_db+0x1a sys/arch/amd64/amd64/db_interface.c:352
x86_ipi_handler() at x86_ipi_handler+0xc6 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x23
end of kernel
end trace frame: 0xc0003eec58, count: -3