panic: pool_cache_item_magic_check: mbufpWlA RcNpIuN Gf:r eSeP Ll iNstO Tm oLdifOiWEeRdED: OiNt eSmYS CaAdLdLr 1306x -

[syzbot]

Hello,

syzbot found the following crash on:

HEAD commit: 6a1018b1 Do not move the cursor to the existing y position..
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=17dd38d7e00000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf87b6915a88cd0d
dashboard link: https://syzkaller.appspot.com/bug?extid=b57dab58c5ff5979dcd0

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+b57dab...@syzkaller.appspotmail.com

panic: pool_cache_item_magic_check: mbufpWlA RcNpIuN Gf:r eSeP Ll iNstO Tm oLdifOiWEeRdED: OiNt eSmYS CaAdLdLr 1306x -f2ff39f7f1d28 0E7XfI0T1 e60 090
+
16Stopped at savectx+0xb1: movl $0,%gs:0x530
TID PID UID PRFLAGS PFLAGS CPU COMMAND
* 61888 65740 0 0x2 0 0 syz-executor.0
150230 53860 0 0x14000 0x200 1 softnet
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffc5810, count: 14
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
pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd807f01e600+16 0x0!=0x7e98d6dc37f89af4
ddb{0}> trace
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffc5810, count: -1
ddb{0}> show registers
rdi 0
rsi 0
rbp 0xffff800020f8b580
rbx 0
rdx 0xffff800020e6d388
rcx 0
rax 0x39
r8 0xffffffff81ce227f kprintf+0x16f
r9 0x1
r10 0x25
r11 0x1c6cc8b14a823a10
r12 0
r13 0
r14 0xffff800020e6d388
r15 0
rip 0xffffffff815413f1 savectx+0xb1
cs 0x8
rflags 0x46
rsp 0xffff800020f8b500
ss 0x10
savectx+0xb1: movl $0,%gs:0x530
ddb{0}> show proc
PROC (syz-executor.0) pid=61888 stat=onproc
flags process=2<EXEC,8ORPHAN> proc=0
pri=17, usrpri=86, nice=20
forw=0xffffffffffffffff, list=0xffff800020e6c9c8,0xffff800020ec6ec8
process=0xffff800020e80b98 user=0xffff800020f86000, vmspace=0xfffffd807efff170
estcpu=36, cpticks=1, pctcpu=0.10
user=0, sys=1, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
31466 225082 68 0 2 0 syz-executor.1
31466 223072 68 0 3 0x4000080 netcon syz-executor.1
79520 169170 0 0 3 0x14200 bored sosplice
*65740 61888 9402 0 7 0x2 syz-executor.0
68 458702 9402 0 3 0x82 nanosleep syz-executor.1
9402 357401 53620 0 3 0x82 thrsleep syz-fuzzer
9402 462710 53620 0 3 0x4000082 nanosleep syz-fuzzer
9402 274159 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 148022 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 213038 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 126134 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 311353 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 273473 53620 0 3 0x4000082 thrsleep syz-fuzzer
9402 252 53620 0 3 0x4000082 kqread syz-fuzzer
9402 414488 53620 0 3 0x4000082 thrsleep syz-fuzzer
53620 35769 63121 0 3 0x10008a pause ksh
63121 273575 36805 0 3 0x92 select sshd
56666 389505 1 0 3 0x100083 ttyin getty
36805 278705 1 0 3 0x80 select sshd
47857 71148 15856 74 3 0x100092 bpf pflogd
15856 91491 1 0 3 0x80 netio pflogd
45642 493433 56791 73 3 0x100090 kqread syslogd
56791 326380 1 0 3 0x100082 netio syslogd
74571 181055 1 77 3 0x100090 poll dhclient
7671 169553 1 0 3 0x80 poll dhclient
15547 130897 0 0 3 0x14200 bored smr
27073 315539 0 0 3 0x14200 pgzero zerothread
79571 156872 0 0 3 0x14200 aiodoned aiodoned
74888 220703 0 0 3 0x14200 syncer update
1090 431237 0 0 3 0x14200 cleaner cleaner
1635 423720 0 0 3 0x14200 reaper reaper
51031 129589 0 0 3 0x14200 pgdaemon pagedaemon
6926 54092 0 0 3 0x14200 bored crynlk
32191 132667 0 0 3 0x14200 bored crypto
40092 89395 0 0 3 0x40014200 acpi0 acpi0
71179 25625 0 0 3 0x40014200 idle1
53860 150230 0 0 7 0x14200 softnet
1885 405497 0 0 3 0x14200 bored systqmp
51234 41995 0 0 3 0x14200 bored systq
409 435325 0 0 3 0x40014200 bored softclock
71898 438189 0 0 3 0x40014200 idle0
1 483852 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{0}> show all locks
CPU 0:
exclusive mutex scxspl r = 0 (0xffffffff8263d4c8)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 mtx_enter_try+0x102
#2 mtx_enter+0x4b sys/kern/kern_lock.c:266
#3 pool_get+0xbf sys/kern/subr_pool.c:578
#4 scsi_xs_io+0x4d sys/scsi/scsi_base.c:760
#5 scsi_xsh_ioh+0x35 sys/scsi/scsi_base.c:607
#6 scsi_iopool_run+0x129 scsi_ioh_pending sys/scsi/scsi_base.c:404 [inline]
#6 scsi_iopool_run+0x129 sys/scsi/scsi_base.c:420
#7 scsi_xsh_runqueue+0x210 sys/scsi/scsi_base.c:596
#8 scsi_xsh_add+0xc9 sys/scsi/scsi_base.c:535
#9 sdstrategy+0x187 sys/scsi/sd.c:585
#10 spec_strategy+0x74 sys/kern/spec_vnops.c:468
#11 ufs_strategy+0x17c
#12 VOP_STRATEGY+0x99 sys/kern/vfs_vops.c:712
#13 bwrite+0x1b9 sys/kern/vfs_bio.c:756
#14 VOP_BWRITE+0x4a sys/kern/vfs_vops.c:724
#15 ufs_mkdir+0x6b7 sys/ufs/ufs/ufs_vnops.c:1248
#16 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450
#17 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051
#18 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#18 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Process 65740 (syz-executor.0) thread 0xffff800020e6d388 (61888)
exclusive kernel_lock &kernel_lock r = 0 (0xffffffff8268ff78)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 __mp_acquire_count+0x51 sys/kern/kern_lock.c:227
#2 mi_switch+0x392 sys/kern/sched_bsd.c:435
#3 sleep_finish+0x113 sys/kern/kern_synch.c:418
#4 sleep_finish_all+0x32 sleep_finish_timeout sys/kern/kern_synch.c:447 [inline]
#4 sleep_finish_all+0x32 sys/kern/kern_synch.c:393
#5 tsleep+0x1cc sys/kern/kern_synch.c:155
#6 biowait+0xa6 sys/kern/vfs_bio.c:1255
#7 bwrite+0x1e4 sys/kern/vfs_bio.c:765
#8 ffs_update+0x2c2 sys/ufs/ffs/ffs_inode.c:113
#9 ufs_mkdir+0x665 sys/ufs/ufs/ufs_vnops.c:1232
#10 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450
#11 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051
#12 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#12 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#13 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd806ed4e3c8)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 rw_enter+0x453 sys/kern/kern_rwlock.c:311
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462
#3 ufs_ihashins+0x45 sys/ufs/ufs/ufs_ihash.c:140
#4 ffs_vget+0x13e sys/ufs/ffs/ffs_vfsops.c:1358
#5 ffs_inode_alloc+0x1cf sys/ufs/ffs/ffs_alloc.c:392
#6 ufs_mkdir+0xf4 sys/ufs/ufs/ufs_vnops.c:1162
#7 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450
#8 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051
#9 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#9 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#10 Xsyscall+0x128
exclusive rrwlock inode r = 0 (0xfffffd806b3866f8)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 rw_enter+0x453 sys/kern/kern_rwlock.c:311
#2 rrw_enter+0x88 sys/kern/kern_rwlock.c:462
#3 VOP_LOCK+0x4b sys/kern/vfs_vops.c:603
#4 vn_lock+0x81 sys/kern/vfs_vnops.c:575
#5 vfs_lookup+0xe6 sys/kern/vfs_lookup.c:419
#6 namei+0x63c sys/kern/vfs_lookup.c:249
#7 domkdirat+0x75 sys/kern/vfs_syscalls.c:3036
#8 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#8 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#9 Xsyscall+0x128
exclusive mutex scxspl r = 0 (0xffffffff8263d4c8)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 mtx_enter_try+0x102
#2 mtx_enter+0x4b sys/kern/kern_lock.c:266
#3 pool_get+0xbf sys/kern/subr_pool.c:578
#4 scsi_xs_io+0x4d sys/scsi/scsi_base.c:760
#5 scsi_xsh_ioh+0x35 sys/scsi/scsi_base.c:607
#6 scsi_iopool_run+0x129 scsi_ioh_pending sys/scsi/scsi_base.c:404 [inline]
#6 scsi_iopool_run+0x129 sys/scsi/scsi_base.c:420
#7 scsi_xsh_runqueue+0x210 sys/scsi/scsi_base.c:596
#8 scsi_xsh_add+0xc9 sys/scsi/scsi_base.c:535
#9 sdstrategy+0x187 sys/scsi/sd.c:585
#10 spec_strategy+0x74 sys/kern/spec_vnops.c:468
#11 ufs_strategy+0x17c
#12 VOP_STRATEGY+0x99 sys/kern/vfs_vops.c:712
#13 bwrite+0x1b9 sys/kern/vfs_bio.c:756
#14 VOP_BWRITE+0x4a sys/kern/vfs_vops.c:724
#15 ufs_mkdir+0x6b7 sys/ufs/ufs/ufs_vnops.c:1248
#16 VOP_MKDIR+0xc6 sys/kern/vfs_vops.c:450
#17 domkdirat+0x121 sys/kern/vfs_syscalls.c:3051
#18 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#18 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Process 53860 (softnet) thread 0xffff800020e18270 (150230)
exclusive rwlock netlock r = 0 (0xffffffff82494738)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 if_input_process+0x84 sys/net/if.c:941
#2 ifiq_process+0x80 sys/net/ifq.c:646
#3 taskq_thread+0x9c sys/kern/kern_task.c:369
#4 proc_trampoline+0x1c
shared rwlock softnet r = 0 (0xffff80000002b0e0)
#0 witness_lock+0x4c5 sys/kern/subr_witness.c:1164
#1 taskq_thread+0x8f sys/kern/kern_task.c:368
#2 proc_trampoline+0x1c
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9484 6402K 6660K 78643K 10725 0
pcb 13 8K 8K 78643K 31 0
rtable 109 3K 3K 78643K 253 0
ifaddr 57 13K 14K 78643K 84 0
counters 43 33K 34K 78643K 53 0
ioctlops 0 0K 4K 78643K 1482 0
iov 0 0K 8K 78643K 5 0
mount 1 1K 1K 78643K 1 0
vnodes 1217 77K 77K 78643K 1262 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 4 0
VM map 2 1K 1K 78643K 2 0
sem 9 0K 1K 78643K 12 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1809 196K 290K 78643K 12766 0
file desc 5 13K 25K 78643K 128 0
sigio 0 0K 0K 78643K 2 0
proc 61 63K 95K 78643K 459 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 119 0
in_multi 59 3K 3K 78643K 73 0
ether_multi 1 0K 0K 78643K 4 0
mrt 0 0K 0K 78643K 2 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 222 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 103 53K 62K 78643K 1320 0
UVM aobj 11 2K 2K 78643K 12 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 20 0
NDP 7 0K 0K 78643K 16 0
temp 74 3036K 3100K 78643K 3901 0
kqueue 3 4K 8K 78643K 17 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 8 0 1 1 0 1 1 0 8 0
plcache 128 20 0 0 1 0 1 1 0 8 0
rtpcb 80 25 0 23 1 0 1 1 0 8 0
rtentry 112 51 0 5 2 0 2 2 0 8 0
unpcb 120 75 0 65 1 0 1 1 0 8 0
syncache 264 4 0 4 1 1 0 1 0 8 0
tcpqe 32 61 0 61 1 1 0 1 0 8 0
tcpcb 544 106 0 101 1 0 1 1 0 8 0
inpcb 280 201 0 193 2 0 2 2 0 8 1
rttmr 72 1 0 1 1 0 1 1 0 8 1
nd6 48 6 0 0 1 0 1 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 20 0 1 1 0 1 1 0 8 0
pfstkey 112 20 0 1 1 0 1 1 0 8 0
pfstate 328 20 0 1 2 0 2 2 0 8 0
pfrule 1360 21 0 16 2 1 1 2 0 8 0
art_heap8 4096 2 0 0 2 0 2 2 0 8 0
art_heap4 256 204 0 2 13 0 13 13 0 8 0
art_table 32 206 0 2 2 0 2 2 0 8 0
art_node 16 50 0 8 1 0 1 1 0 8 0
sysvmsgpl 40 4 0 4 1 0 1 1 0 8 1
semapl 112 8 0 1 1 0 1 1 0 8 0
shmpl 112 10 0 1 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 1557 0 152 89 0 89 89 0 8 0
ffsino 272 1557 0 152 94 0 94 94 0 8 0
nchpl 144 1961 0 346 61 0 61 61 0 8 0
uvmvnodes 72 1631 0 0 30 0 30 30 0 8 0
vnodes 208 1631 0 0 86 0 86 86 0 8 0
namei 1024 5175 0 5175 1 0 1 1 0 8 1
percpumem 16 37 0 5 1 0 1 1 0 8 0
vcpupl 1984 3 0 0 1 0 1 1 0 8 0
vmpool 560 9 0 6 1 0 1 1 0 8 0
scxspl 192 5713 0 5713 8 1 7 7 0 8 7
plimitpl 152 23 0 15 1 0 1 1 0 8 0
sigapl 424 344 0 312 4 0 4 4 0 8 0
futexpl 56 1670 0 1670 1 0 1 1 0 8 1
knotepl 112 63 0 44 1 0 1 1 0 8 0
kqueuepl 144 21 0 18 1 0 1 1 0 8 0
pipelkpl 48 98 0 88 1 0 1 1 0 8 0
pipepl 120 196 0 177 1 0 1 1 0 8 0
fdescpl 496 328 0 312 3 0 3 3 0 8 0
filepl 152 1811 0 1707 5 0 5 5 0 8 0
lockfpl 104 40 0 39 1 0 1 1 0 8 0
lockfspl 48 12 0 11 1 0 1 1 0 8 0
sessionpl 112 18 0 7 1 0 1 1 0 8 0
pgrppl 48 20 0 9 1 0 1 1 0 8 0
ucredpl 96 119 0 110 1 0 1 1 0 8 0
zombiepl 144 312 0 312 1 0 1 1 0 8 1
processpl 984 344 0 312 5 0 5 5 0 8 0
procpl 624 564 0 522 4 0 4 4 0 8 0
sosppl 128 4 0 4 1 0 1 1 0 8 1
sockpl 400 301 0 280 4 0 4 4 0 8 1
mcl64k 65536 3 0 0 1 0 1 1 0 8 0
mcl16k 16384 1 0 0 1 0 1 1 0 8 0
mcl12k 12288 2 0 0 1 0 1 1 0 8 0
mcl9k 9216 3 0 0 1 0 1 1 0 8 0
mcl8k 8192 1 0 0 1 0 1 1 0 8 0
mcl4k 4096 3 0 0 1 0 1 1 0 8 0
mcl2k 2048 188 0 0 23 0 23 23 0 8 0
mtagpl 80 11 0 0 1 0 1 1 0 8 0
mbufpl 256 197 0 0 12 0 12 12 0 8 0
bufpl 280 4249 0 190 290 0 290 290 0 8 0
anonpl 16 48712 0 34372 74 1 73 73 0 124 14
amapchunkpl 152 1764 0 1620 11 0 11 11 0 158 4
amappl16 192 1524 0 755 50 0 50 50 0 8 11
amappl15 184 2 0 1 2 1 1 1 0 8 0
amappl14 176 22 0 18 1 0 1 1 0 8 0
amappl13 168 26 0 25 1 0 1 1 0 8 0
amappl12 160 15 0 14 2 1 1 1 0 8 0
amappl11 152 150 0 131 1 0 1 1 0 8 0
amappl10 144 18 0 14 1 0 1 1 0 8 0
amappl9 136 397 0 393 1 0 1 1 0 8 0
amappl8 128 290 0 277 1 0 1 1 0 8 0
amappl7 120 118 0 107 1 0 1 1 0 8 0
amappl6 112 121 0 113 1 0 1 1 0 8 0
amappl5 104 182 0 168 1 0 1 1 0 8 0
amappl4 96 530 0 499 1 0 1 1 0 8 0
amappl3 88 112 0 107 1 0 1 1 0 8 0
amappl2 80 1699 0 1628 3 1 2 3 0 8 0
amappl1 72 17285 0 16845 25 14 11 20 0 8 1
amappl 80 820 0 771 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 11 0 1 1 0 1 1 0 8 0
uaddrrnd 24 337 0 318 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 337 0 318 1 0 1 1 0 8 0
vmmpekpl 168 6552 0 6521 2 0 2 2 0 8 0
vmmpepl 168 46985 0 45078 105 6 99 99 0 357 12
vmsppl 368 336 0 318 2 0 2 2 0 8 0
pdppl 4096 682 0 639 6 0 6 6 0 8 0
pvpl 32 157490 0 140004 176 0 176 176 0 265 34
pmappl 232 336 0 318 2 0 2 2 0 8 0
extentpl 40 46 0 29 1 0 1 1 0 8 0
phpool 112 262 0 3 8 0 8 8 0 8 0


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
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syzbot will keep track of this bug report. See:
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[Anton Lindqvist]

#syz dup: pool: cpu free list modified: mbufpl