panicW: ARpNoIoNlG_:c aScPhLe _NiOteT mL_OmWaEgRiEc_D cOhNe cSkY: SCmAbLuLf pl2 2c1p4u 23f6r0e46e0 lEisXItT m0o ad

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syzbot

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May 26, 2020, 9:17:14 AM5/26/20
to syzkaller-o...@googlegroups.com
Hello,

syzbot found the following crash on:

HEAD commit: 4e2f099e sync from MAKEDEV.md
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=170b6016100000
kernel config: https://syzkaller.appspot.com/x/.config?x=bf87b6915a88cd0d
dashboard link: https://syzkaller.appspot.com/bug?extid=b172bd0be6cd543047bc

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+b172bd...@syzkaller.appspotmail.com

panicW: ARpNoIoNlG_:c aScPhLe _NiOteT mL_OmWaEgRiEc_D cOhNe cSkY: SCmAbLuLf pl2 2c1p4u 23f6r0e46e0 lEisXItT m0o ad
i
fStopped at savectx+0xb1: movl $0,%gs:0x530
TID PID UID PRFLAGS PFLAGS CPU COMMAND
* 63287 72384 0 0x2 0 1 syz-executor.1
339181 54047 0 0x12 0 0 sshd
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffe3eb0, 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{1}>
ddb{1}> set $lines = 0
ddb{1}> set $maxwidth = 0
ddb{1}> show panic
pool_cache_item_magic_check: mbufpl cpu free list modified: item addr 0xfffffd8068e3d900+16 0x0!=0x294b71bdefa9d10b
ddb{1}> trace
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffe3eb0, count: -1
ddb{1}> show registers
rdi 0
rsi 0
rbp 0xffff800021f832a0
rbx 0
rdx 0x8b
rcx 0x2
rax 0x3a
r8 0xffffffff8210a11f kprintf+0x16f
r9 0x1
r10 0x2
r11 0x8e3d8e4369933997
r12 0
r13 0
r14 0xffff800020ecf128
r15 0
rip 0xffffffff8115d3f1 savectx+0xb1
cs 0x8
rflags 0x46
rsp 0xffff800021f83220
ss 0x10
savectx+0xb1: movl $0,%gs:0x530
ddb{1}> show proc
PROC (syz-executor.1) pid=63287 stat=onproc
flags process=2<EXEC,8ORPHAN> proc=0
pri=16, usrpri=54, nice=20
forw=0xffffffffffffffff, list=0xffff800020ece4f8,0xffff800020ece028
process=0xffff800020ed8bb0 user=0xffff800021f7e000, vmspace=0xfffffd807efff5c0
estcpu=4, cpticks=1, pctcpu=0.3
user=0, sys=1, intr=0
ddb{1}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
64891 461231 72384 0 2 0 syz-executor.1
*72384 63287 18635 0 7 0x2 syz-executor.1
43727 94719 0 0 3 0x14200 acct acct
56888 434341 0 0 3 0x14200 bored sosplice
16727 100802 18635 0 3 0x82 piperd syz-executor.0
18635 24963 18502 0 3 0x82 thrsleep syz-fuzzer
18635 21350 18502 0 2 0x4000482 syz-fuzzer
18635 399744 18502 0 3 0x4000082 thrsleep syz-fuzzer
18635 427369 18502 0 3 0x4000082 thrsleep syz-fuzzer
18635 229518 18502 0 3 0x4000082 thrsleep syz-fuzzer
18635 380333 18502 0 3 0x4000082 thrsleep syz-fuzzer
18635 150102 18502 0 3 0x4000082 thrsleep syz-fuzzer
18635 399139 18502 0 2 0x4000002 syz-fuzzer
18635 5757 18502 0 2 0x4000002 syz-fuzzer
18635 307095 18502 0 3 0x4000082 thrsleep syz-fuzzer
18502 145376 54047 0 3 0x10008a pause ksh
54047 339181 35917 0 7 0x12 sshd
95172 284131 1 0 3 0x100083 ttyin getty
35917 494958 1 0 3 0x80 select sshd
96642 482120 53704 74 3 0x100092 bpf pflogd
53704 291621 1 0 3 0x80 netio pflogd
33663 426200 57260 73 3 0x100090 kqread syslogd
57260 7559 1 0 3 0x100082 netio syslogd
28511 519518 1 77 3 0x100090 poll dhclient
65936 516021 1 0 3 0x80 poll dhclient
11676 332729 0 0 3 0x14200 bored smr
93434 426086 0 0 2 0x14200 zerothread
99432 289126 0 0 3 0x14200 aiodoned aiodoned
36422 300508 0 0 3 0x14200 syncer update
53506 113263 0 0 3 0x14200 cleaner cleaner
95510 488207 0 0 3 0x14200 reaper reaper
11337 103437 0 0 3 0x14200 pgdaemon pagedaemon
61506 431770 0 0 3 0x14200 bored crynlk
79062 285566 0 0 3 0x14200 bored crypto
84696 117005 0 0 3 0x40014200 acpi0 acpi0
85980 18767 0 0 3 0x40014200 idle1
82492 30185 0 0 3 0x14200 bored softnet
84475 175683 0 0 3 0x14200 bored systqmp
61305 412363 0 0 3 0x14200 bored systq
1718 396561 0 0 3 0x40014200 bored softclock
4793 476608 0 0 3 0x40014200 idle0
1 465712 0 0 3 0x82 wait init
0 0 -1 0 3 0x10200 scheduler swapper
ddb{1}> show all locks
CPU 1:
exclusive mutex vmmpekpl r = 0 (0xffffffff8264f970)
#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 pool_put+0x64 sys/kern/subr_pool.c:792
#4 uvm_unmap_detach+0x231 sys/uvm/uvm_map.c:1581
#5 uvm_map+0xe0c sys/uvm/uvm_map.c:1420
#6 uvm_km_kmemalloc_pla+0x11d sys/uvm/uvm_km.c:335
#7 uvm_uarea_alloc+0x51 sys/uvm/uvm_glue.c:274
#8 fork1+0x271 sys/kern/kern_fork.c:365
#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
Process 72384 (syz-executor.1) thread 0xffff800020ecf128 (63287)
exclusive kernel_lock &kernel_lock r = 1 (0xffffffff8268a470)
#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 vmmpekpl r = 0 (0xffffffff8264f970)
#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 pool_put+0x64 sys/kern/subr_pool.c:792
#4 uvm_unmap_detach+0x231 sys/uvm/uvm_map.c:1581
#5 uvm_map+0xe0c sys/uvm/uvm_map.c:1420
#6 uvm_km_kmemalloc_pla+0x11d sys/uvm/uvm_km.c:335
#7 uvm_uarea_alloc+0x51 sys/uvm/uvm_glue.c:274
#8 fork1+0x271 sys/kern/kern_fork.c:365
#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
Process 54047 (sshd) thread 0xffff800020ed1390 (339181)
exclusive rwlock netlock r = 0 (0xffffffff824b44a8)
#0 witness_lock+0x4c7 stacktrace_save sys/sys/stacktrace.h:36 [inline]
#0 witness_lock+0x4c7 sys/kern/subr_witness.c:1164
#1 solock+0x5a sys/kern/uipc_socket2.c:282
#2 sosend+0x559 sys/kern/uipc_socket.c:537
#3 dofilewritev+0x1b6 sys/kern/sys_generic.c:365
#4 sys_write+0x83 sys/kern/sys_generic.c:285
#5 syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
#5 syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
#6 Xsyscall+0x128
ddb{1}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 9507 6426K 6932K 78643K 10866 0
pcb 13 8K 8K 78643K 57 0
rtable 105 3K 3K 78643K 302 0
ifaddr 63 13K 13K 78643K 85 0
counters 43 33K 34K 78643K 47 0
ioctlops 0 0K 4K 78643K 1472 0
iov 0 0K 12K 78643K 10 0
mount 1 1K 1K 78643K 1 0
vnodes 1219 77K 77K 78643K 1320 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 1K 78643K 2 0
VM map 2 1K 1K 78643K 2 0
sem 12 0K 0K 78643K 24 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1824 197K 290K 78643K 13058 0
file desc 5 13K 25K 78643K 197 0
sigio 0 0K 0K 78643K 2 0
proc 61 63K 95K 78643K 483 0
subproc 32 2K 2K 78643K 51 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 40 2K 2K 78643K 98 0
ether_multi 1 0K 0K 78643K 10 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 43 201K 201K 78643K 43 0
exec 0 0K 1K 78643K 238 0
pfkey data 0 0K 0K 78643K 2 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 120 38K 39K 78643K 1569 0
UVM aobj 6 2K 2K 78643K 6 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 40 0
NDP 10 0K 0K 78643K 22 0
temp 88 3033K 3101K 78643K 4351 0
kqueue 3 4K 12K 78643K 20 0
SYN cache 2 16K 16K 78643K 2 0
ddb{1}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
arp 64 8 0 2 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 72 0 28 2 0 2 2 0 8 0
unpcb 120 165 0 155 1 0 1 1 0 8 0
syncache 264 5 0 5 2 2 0 1 0 8 0
tcpqe 32 769 0 769 1 1 0 1 0 8 0
tcpcb 544 75 0 71 1 0 1 1 0 8 0
inpcb 280 268 0 261 2 1 1 2 0 8 0
nd6 48 13 0 7 1 0 1 1 0 8 0
pkpcb 40 2 0 2 1 1 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 25 0 4 1 0 1 1 0 8 0
pfstkey 112 25 0 4 1 0 1 1 0 8 0
pfstate 328 25 0 4 2 0 2 2 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 256 328 0 140 14 2 12 13 0 8 0
art_table 32 329 0 140 2 0 2 2 0 8 0
art_node 16 71 0 31 1 0 1 1 0 8 0
sysvmsgpl 40 5 0 4 1 0 1 1 0 8 0
semapl 112 22 0 12 1 0 1 1 0 8 0
shmpl 112 4 0 0 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 1642 0 236 89 0 89 89 0 8 0
ffsino 272 1642 0 236 96 1 95 95 0 8 0
nchpl 144 2115 0 521 60 0 60 60 0 8 0
uvmvnodes 72 1761 0 0 33 0 33 33 0 8 0
vnodes 208 1761 0 0 93 0 93 93 0 8 0
namei 1024 5744 0 5744 2 1 1 1 0 8 1
percpumem 16 34 0 2 1 0 1 1 0 8 0
vcpupl 1984 1 0 0 1 0 1 1 0 8 0
vmpool 560 1 0 0 1 0 1 1 0 8 0
scsiplug 64 2 0 2 1 0 1 1 0 8 1
scxspl 192 6942 0 6942 8 7 1 7 0 8 1
plimitpl 152 28 0 20 1 0 1 1 0 8 0
sigapl 424 411 0 378 4 0 4 4 0 8 0
futexpl 56 2308 0 2308 1 0 1 1 0 8 1
knotepl 112 92 0 73 1 0 1 1 0 8 0
kqueuepl 144 38 0 36 1 0 1 1 0 8 0
pipelkpl 48 120 0 110 1 0 1 1 0 8 0
pipepl 120 240 0 221 1 0 1 1 0 8 0
fdescpl 496 394 0 378 3 0 3 3 0 8 0
filepl 152 2309 0 2209 6 1 5 5 0 8 1
lockfpl 104 38 0 37 1 0 1 1 0 8 0
lockfspl 48 17 0 16 1 0 1 1 0 8 0
sessionpl 112 19 0 8 1 0 1 1 0 8 0
pgrppl 48 21 0 10 1 0 1 1 0 8 0
ucredpl 96 154 0 144 1 0 1 1 0 8 0
zombiepl 144 378 0 378 2 1 1 1 0 8 1
processpl 984 411 0 378 6 1 5 5 0 8 0
procpl 624 757 0 715 4 0 4 4 0 8 0
sosppl 128 5 0 5 2 1 1 1 0 8 1
sockpl 400 460 0 441 5 2 3 4 0 8 1
mcl64k 65536 4 0 0 1 0 1 1 0 8 0
mcl12k 12288 2 0 0 1 0 1 1 0 8 0
mcl9k 9216 1 0 0 1 0 1 1 0 8 0
mcl4k 4096 5 0 0 1 0 1 1 0 8 0
mcl2k2 2112 1 0 0 1 0 1 1 0 8 0
mcl2k 2048 176 0 0 21 0 21 21 0 8 0
mtagpl 80 24 0 0 1 0 1 1 0 8 0
mbufpl 256 503 0 0 31 0 31 31 0 8 0
bufpl 280 4992 0 135 347 0 347 347 0 8 0
anonpl 16 55042 0 43598 75 1 74 74 0 124 16
amapchunkpl 152 2156 0 2016 9 2 7 8 0 158 0
amappl16 192 1848 0 1094 50 4 46 50 0 8 7
amappl15 184 9 0 7 1 0 1 1 0 8 0
amappl14 176 97 0 89 1 0 1 1 0 8 0
amappl13 168 47 0 42 1 0 1 1 0 8 0
amappl12 160 78 0 73 2 1 1 1 0 8 0
amappl11 152 55 0 40 1 0 1 1 0 8 0
amappl10 144 18 0 11 1 0 1 1 0 8 0
amappl9 136 357 0 355 1 0 1 1 0 8 0
amappl8 128 443 0 411 2 0 2 2 0 8 0
amappl7 120 127 0 114 1 0 1 1 0 8 0
amappl6 112 28 0 23 1 0 1 1 0 8 0
amappl5 104 487 0 471 1 0 1 1 0 8 0
amappl4 96 507 0 476 1 0 1 1 0 8 0
amappl3 88 115 0 108 1 0 1 1 0 8 0
amappl2 80 2187 0 2126 2 0 2 2 0 8 0
amappl1 72 18785 0 18358 23 13 10 18 0 8 0
amappl 80 1028 0 982 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 5 0 0 1 0 1 1 0 8 0
uaddrrnd 24 395 0 378 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 395 0 378 1 0 1 1 0 8 0
vmmpekpl 168 7070 0 7039 2 0 2 2 0 8 0
vmmpepl 168 55626 0 53746 126 13 113 113 0 357 28
vmsppl 368 394 0 378 2 0 2 2 0 8 0
pdppl 4096 798 0 757 6 0 6 6 0 8 0
pvpl 32 178238 0 163703 181 4 177 177 0 265 34
pmappl 232 394 0 378 3 1 2 2 0 8 1
extentpl 40 53 0 36 1 0 1 1 0 8 0
phpool 112 281 0 9 8 0 8 8 0 8 0
ddb{1}> machine ddbcpu 0
Stopped at x86_ipi_db+0x1a: addq $0x8,%rsp
x86_ipi_db(ffffffff824b2ff0) 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
x86_bus_space_io_read_1(3f8,5) at x86_bus_space_io_read_1+0x3c sys/arch/amd64/amd64/bus_space.c:639
comcnputc(800,69) at comcnputc+0xb8 sys/dev/ic/com.c:1250
cnputc(69) at cnputc+0x4c sys/dev/cons.c:239
kputchar(69,5,0) at kputchar+0x219 sys/kern/subr_prf.c:343
kprintf() at kprintf+0x15c sys/kern/subr_prf.c:700
panic(ffffffff821fb214) at panic+0xf3 vprintf sys/kern/subr_prf.c:528 [inline]
panic(ffffffff821fb214) at panic+0xf3 sys/kern/subr_prf.c:197
pool_cache_get(ffffffff82667020) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline]
pool_cache_get(ffffffff82667020) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884
pool_get(ffffffff82667020,2) at pool_get+0x91 sys/kern/subr_pool.c:572
m_copym(fffffd8068e3c600,0,580,2) at m_copym+0x174 m_get sys/kern/uipc_mbuf.c:250 [inline]
m_copym(fffffd8068e3c600,0,580,2) at m_copym+0x174 sys/kern/uipc_mbuf.c:667
tcp_output(ffff800000a0b100) at tcp_output+0x15ba sys/netinet/tcp_output.c:673
tcp_usrreq(fffffd806eb407d8,9,fffffd8068e3c600,0,0,ffff800020ed1390) at tcp_usrreq+0xa55
end trace frame: 0xffff800020ed7480, count: 0
ddb{0}> trace
x86_ipi_db(ffffffff824b2ff0) 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
x86_bus_space_io_read_1(3f8,5) at x86_bus_space_io_read_1+0x3c sys/arch/amd64/amd64/bus_space.c:639
comcnputc(800,69) at comcnputc+0xb8 sys/dev/ic/com.c:1250
cnputc(69) at cnputc+0x4c sys/dev/cons.c:239
kputchar(69,5,0) at kputchar+0x219 sys/kern/subr_prf.c:343
kprintf() at kprintf+0x15c sys/kern/subr_prf.c:700
panic(ffffffff821fb214) at panic+0xf3 vprintf sys/kern/subr_prf.c:528 [inline]
panic(ffffffff821fb214) at panic+0xf3 sys/kern/subr_prf.c:197
pool_cache_get(ffffffff82667020) at pool_cache_get+0x323 pool_cache_item_magic_check sys/kern/subr_pool.c:1781 [inline]
pool_cache_get(ffffffff82667020) at pool_cache_get+0x323 sys/kern/subr_pool.c:1884
pool_get(ffffffff82667020,2) at pool_get+0x91 sys/kern/subr_pool.c:572
m_copym(fffffd8068e3c600,0,580,2) at m_copym+0x174 m_get sys/kern/uipc_mbuf.c:250 [inline]
m_copym(fffffd8068e3c600,0,580,2) at m_copym+0x174 sys/kern/uipc_mbuf.c:667
tcp_output(ffff800000a0b100) at tcp_output+0x15ba sys/netinet/tcp_output.c:673
tcp_usrreq(fffffd806eb407d8,9,fffffd8068e3c600,0,0,ffff800020ed1390) at tcp_usrreq+0xa55
sosend(fffffd806eb407d8,0,ffff800020ed7548,0,0,80) at sosend+0x671 sys/kern/uipc_socket.c:549
dofilewritev(ffff800020ed1390,4,ffff800020ed7548,0,ffff800020ed7630) at dofilewritev+0x1b6 sys/kern/sys_generic.c:365
sys_write(ffff800020ed1390,ffff800020ed75e0,ffff800020ed7630) at sys_write+0x83 sys/kern/sys_generic.c:285
syscall(ffff800020ed76b0) at syscall+0x4a4 mi_syscall sys/sys/syscall_mi.h:102 [inline]
syscall(ffff800020ed76b0) at syscall+0x4a4 sys/arch/amd64/amd64/trap.c:570
Xsyscall() at Xsyscall+0x128
end of kernel
end trace frame: 0x7f7ffffd9330, count: -19
ddb{0}> machine ddbcpu 1
Stopped at savectx+0xb1: movl $0,%gs:0x530
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffe3eb0, count: 14
ddb{1}> trace
savectx() at savectx+0xb1
end of kernel
end trace frame: 0x7f7ffffe3eb0, count: -1


---
This bug is generated by a bot. It may contain errors.
See https://goo.gl/tpsmEJ for more information about syzbot.
syzbot engineers can be reached at syzk...@googlegroups.com.

syzbot will keep track of this bug report. See:
https://goo.gl/tpsmEJ#status for how to communicate with syzbot.

Anton Lindqvist

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May 27, 2020, 3:26:55 AM5/27/20
to syzbot, syzkaller-o...@googlegroups.com
#syz dup: pool: cpu free list modified: mbufpl
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