kernel: double fault trap, code=NUM (2)

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit: a0e2ca3ce324 sshsk_sign: trim call to sshkey_fingerprint()
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=12d58450700000
kernel config: https://syzkaller.appspot.com/x/.config?x=fe55924c11e64b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=d3e202981a9681e89eeb

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

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d3e202...@syzkaller.appspotmail.com

kernel: double fault trap, code=0
Stopped at restore_saved+0x35: xorq 0x30(%rsp),%r11
ddb>
ddb> set $lines = 0
ddb> set $maxwidth = 0
ddb> show panic
the kernel did not panic
ddb> trace
end trace frame: 0x0, count: -1
ddb> show registers
rdi 0xffffffff82c5e000 end+0x25e000
rsi 0xffff80002166ba48
rbp 0
rbx 0
rdx 0
rcx 0xfffffd8061664538
rax 0x23
r8 0
r9 0
r10 0x2ee9d06d88da4b76
r11 0xb857a886b2fd0323
r12 0xffff80002166ba48
r13 0xffff8000216fe000
r14 0xffff80002166f500
r15 0xffff80002166ba48
rip 0xffffffff8205e1e7 restore_saved+0x35
cs 0x8
rflags 0x10046 __ALIGN_SIZE+0xf046
rsp 0
ss 0x10
restore_saved+0x35: xorq 0x30(%rsp),%r11
ddb> show proc
PROC (syz-executor.0) pid=172114 stat=onproc
flags process=0 proc=0
pri=84, usrpri=84, nice=20
forw=0xffffffffffffffff, list=0xffff80002166aa88,0xffff80002166a7f8
process=0xffff80002312b790 user=0xffff8000216fe000, vmspace=0xfffffd8061665448
estcpu=34, cpticks=8, pctcpu=0.0
user=0, sys=0, intr=0
ddb> ps
PID TID PPID UID S FLAGS WAIT COMMAND
*80207 172114 57985 0 7 0 syz-executor.0
80207 72676 57985 0 3 0x4000000 fltagain2 syz-executor.0
80207 235727 57985 0 3 0x4000000 biowait syz-executor.0
80207 91598 57985 0 3 0x4000080 fsleep syz-executor.0
74265 280075 66905 0 3 0x2 biowait syz-executor.3
42531 36942 66905 0 3 0x82 piperd syz-executor.1
70284 143090 0 0 3 0x14200 acct acct
70508 16261 66905 0 3 0x82 nanoslp syz-executor.2
21062 138793 1 0 3 0x100083 ttyin getty
13840 122551 0 0 3 0x14200 bored sosplice
57985 471715 66905 0 3 0x82 nanoslp syz-executor.0
66905 300403 2698 0 3 0x82 kqread syz-fuzzer
66905 438545 2698 0 3 0x4000082 nanoslp syz-fuzzer
66905 20493 2698 0 3 0x4000082 thrsleep syz-fuzzer
66905 178005 2698 0 3 0x4000082 thrsleep syz-fuzzer
66905 134701 2698 0 3 0x4000082 thrsleep syz-fuzzer
66905 36581 2698 0 3 0x4000082 thrsleep syz-fuzzer
66905 494811 2698 0 3 0x4000082 thrsleep syz-fuzzer
2698 184178 31835 0 3 0x10008a sigsusp ksh
31835 196795 4582 0 3 0x9a poll sshd
4582 429116 1 0 3 0x88 poll sshd
45270 29688 40999 73 3 0x100090 kqread syslogd
40999 179178 1 0 3 0x100082 netio syslogd
13659 247902 1 0 3 0x100080 kqread resolvd
44469 107561 93872 77 3 0x100092 kqread dhcpleased
32045 180486 93872 77 3 0x100092 kqread dhcpleased
93872 383897 1 0 3 0x80 kqread dhcpleased
96401 323239 0 0 3 0x14200 bored smr
29417 479734 0 0 2 0x14200 zerothread
94540 197143 0 0 3 0x14200 aiodoned aiodoned
16542 315728 0 0 3 0x14200 syncer update
82337 378143 0 0 3 0x14200 cleaner cleaner
18907 378517 0 0 3 0x14200 reaper reaper
19579 15452 0 0 3 0x14200 pgdaemon pagedaemon
43818 478317 0 0 3 0x14200 bored viomb
69231 273573 0 0 3 0x40014200 acpi0 acpi0
94914 456408 0 0 3 0x14200 bored softnet
78366 279394 0 0 3 0x14200 bored systqmp
99140 27491 0 0 3 0x14200 bored systq
6474 328514 0 0 3 0x40014200 bored softclock
11614 148179 0 0 3 0x40014200 idle0
1 45567 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 10176 6449K 6920K 78643K 15202 0
pcb 13 13K 15K 78643K 343 0
rtable 144 18K 19K 78643K 3414 0
ifaddr 67 16K 16K 78643K 1243 0
sysctl 2 0K 0K 78643K 2 0
counters 23 16K 17K 78643K 73 0
ioctlops 0 0K 4K 78643K 1925 0
iov 1 12K 16K 78643K 504 0
mount 1 1K 1K 78643K 1 0
log 0 0K 0K 78643K 4 0
vnodes 1293 81K 81K 78643K 2561 0
UFS quota 1 32K 32K 78643K 1 0
UFS mount 5 36K 36K 78643K 5 0
shm 2 1K 5K 78643K 17 0
VM map 2 0K 0K 78643K 2 0
sem 12 0K 0K 78643K 209 0
dirhash 12 2K 2K 78643K 12 0
ACPI 1697 195K 286K 78643K 12598 0
file desc 7 21K 41K 78643K 2967 0
sigio 0 0K 0K 78643K 6 0
proc 62 55K 71K 78643K 642 0
subproc 52 6K 6K 78643K 156 0
NFS srvsock 1 0K 0K 78643K 1 0
NFS daemon 1 16K 16K 78643K 1 0
ip_moptions 0 0K 0K 78643K 80 0
in_multi 44 2K 3K 78643K 237 0
ether_multi 1 0K 0K 78643K 38 0
mrt 1 0K 0K 78643K 28 0
ISOFS mount 1 32K 32K 78643K 1 0
MSDOSFS mount 1 16K 16K 78643K 1 0
ttys 175 784K 784K 78643K 175 0
exec 0 0K 2K 78643K 755 0
pfkey data 0 0K 1K 78643K 67 0
tdb 3 0K 0K 78643K 3 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 250 164K 164K 78643K 37433 0
UVM aobj 30 2K 2K 78643K 36 0
memdesc 1 4K 4K 78643K 1 0
crypto data 1 1K 1K 78643K 1 0
ip6_options 0 0K 0K 78643K 129 0
NDP 8 0K 1K 78643K 86 0
temp 100 4206K 4270K 78643K 20046 0
kqueue 13 15K 20K 78643K 121 0
SYN cache 2 16K 16K 78643K 2 0
ddb> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
rtpcb 120 880 0 877 13 11 2 3 0 8 1
rtentry 112 172 0 126 2 0 2 2 0 8 0
unpcb 136 2459 0 2446 21 20 1 6 0 8 0
syncache 296 35 0 35 7 7 0 1 0 8 0
tcpqe 32 148 0 148 4 4 0 1 0 8 0
tcpcb 736 961 0 957 36 28 8 10 0 8 7
arp 88 26 0 18 1 0 1 1 0 8 0
ipq 40 1 0 1 1 1 0 1 0 8 0
ipqe 40 44 0 44 1 1 0 1 0 8 0
inpcb 304 2728 0 2721 63 57 6 14 0 8 5
rttmr 72 6 0 6 2 2 0 1 0 8 0
nd6 48 40 0 31 1 0 1 1 0 8 0
pkpcb 40 7 0 7 2 2 0 1 0 8 0
kcovpl 48 12 0 8 1 0 1 1 0 8 0
ppxss 1152 12 0 12 5 5 0 1 0 8 0
pfstscr 40 6 0 6 2 1 1 1 0 8 1
pfosfp 40 1 0 0 1 0 1 1 0 8 0
pfosfpen 112 1 0 0 1 0 1 1 0 8 0
pfrktable 1344 204 0 191 2 0 2 2 0 8 0
pftag 88 37 0 31 1 0 1 1 0 8 0
pfqueue 264 1 0 0 1 0 1 1 0 8 0
pfstitem 24 2 0 2 1 1 0 1 0 8 0
pfstkey 112 12 0 12 2 1 1 1 0 8 1
pfstate 320 6 0 6 2 1 1 1 0 8 1
pfrule 1360 1006 0 818 16 0 16 16 0 8 0
art_heap8 4096 1 0 0 1 0 1 1 0 8 0
art_heap4 256 699 0 494 18 5 13 18 0 8 0
art_table 32 700 0 494 3 0 3 3 0 8 0
art_node 16 168 0 129 1 0 1 1 0 8 0
sysvmsgpl 40 38 0 5 1 0 1 1 0 8 0
semapl 112 207 0 197 1 0 1 1 0 8 0
shmpl 112 33 0 6 1 0 1 1 0 8 0
dirhash 1024 17 0 0 3 0 3 3 0 8 0
dino2pl 256 5264 0 3850 89 0 89 89 0 8 0
ffsino 240 5264 0 3850 84 0 84 84 0 8 0
nchpl 144 9285 0 7701 61 0 61 61 0 8 0
uvmvnodes 80 5926 0 0 121 0 121 121 0 8 0
vnodes 224 5926 0 0 349 0 349 349 0 8 0
namei 1024 35117 0 35116 4 3 1 1 0 8 0
vcpupl 1984 73 0 1 10 0 10 10 0 8 0
vmpool 528 79 0 7 5 0 5 5 0 8 0
pfiaddrpl 120 102 0 84 1 0 1 1 0 8 0
scxspl 216 31107 0 31105 16 15 1 8 0 8 0
plimitpl 152 251 0 241 1 0 1 1 0 8 0
sigapl 424 3164 0 3131 6 1 5 5 0 8 1
futexpl 64 29265 0 29264 4 3 1 1 0 8 0
knotepl 112 2131 0 2080 3 0 3 3 0 8 0
kqueuepl 184 550 0 541 10 9 1 4 0 8 0
pipepl 304 615 0 598 20 16 4 11 0 8 2
fdescpl 432 3149 0 3131 3 0 3 3 0 8 0
filepl 120 25078 0 24926 55 47 8 13 0 8 3
lockfpl 104 862 0 859 3 2 1 2 0 8 0
lockfspl 48 189 0 186 1 0 1 1 0 8 0
sessionpl 144 28 0 16 1 0 1 1 0 8 0
pgrppl 48 31 0 19 1 0 1 1 0 8 0
ucredpl 96 2415 0 2405 1 0 1 1 0 8 0
zombiepl 144 3131 0 3130 1 0 1 1 0 8 0
processpl 1000 3164 0 3130 5 0 5 5 0 8 0
procpl 672 8086 0 8043 13 8 5 6 0 8 0
sosppl 168 37 0 37 7 7 0 1 0 8 0
sockpl 448 6074 0 6048 119 108 11 22 0 8 7
mcl64k 65536 457 0 457 8 7 1 1 0 8 1
mcl16k 16384 76 0 76 9 8 1 1 0 8 1
mcl12k 12288 296 0 296 6 5 1 1 0 8 1
mcl9k 9216 41 0 41 12 12 0 1 0 8 0
mcl8k 8192 206 0 206 7 6 1 1 0 8 1
mcl4k 4096 344 0 344 5 4 1 1 0 8 1
mcl2k2 2112 22 0 22 8 8 0 1 0 8 0
mcl2k 2048 82186 0 82125 25 16 9 16 0 8 0
mtagpl 96 577 0 309 8 1 7 7 0 8 0
mbufpl 256 172806 0 172081 525 472 53 441 0 8 5
bufpl 288 9492 0 3075 459 0 459 459 0 8 0
anonpl 24 855232 0 837553 151 39 112 135 0 188 1
amapchunkpl 152 102970 0 102376 65 38 27 37 0 158 1
amappl16 200 7582 0 6940 54 19 35 45 0 8 1
amappl15 192 13 0 11 2 1 1 1 0 8 0
amappl14 184 106 0 105 1 0 1 1 0 8 0
amappl13 176 1104 0 1102 1 0 1 1 0 8 0
amappl12 168 812 0 808 1 0 1 1 0 8 0
amappl11 160 284 0 273 1 0 1 1 0 8 0
amappl10 152 411 0 406 1 0 1 1 0 8 0
amappl9 144 468 0 464 1 0 1 1 0 8 0
amappl8 136 835 0 777 3 0 3 3 0 8 0
amappl7 128 394 0 386 1 0 1 1 0 8 0
amappl6 120 195 0 176 1 0 1 1 0 8 0
amappl5 112 3084 0 3068 1 0 1 1 0 8 0
amappl4 104 1277 0 1253 1 0 1 1 0 8 0
amappl3 96 1715 0 1697 1 0 1 1 0 8 0
amappl2 88 1588 0 1547 2 0 2 2 0 8 0
amappl1 80 58252 0 57808 12 1 11 12 0 8 0
amappl 88 36898 0 36738 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
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 72 35 0 6 1 0 1 1 0 8 0
uaddrrnd 24 3228 0 3138 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 3228 0 3138 1 0 1 1 0 8 0
vmmpekpl 168 24528 0 24496 2 0 2 2 0 8 0
vmmpepl 168 290922 0 288833 192 90 102 129 0 357 2
vmsppl 272 3227 0 3138 8 1 7 7 0 8 0
rwobjpl 24 73993 0 66619 45 0 45 45 0 8 0
pdppl 4096 6464 0 6348 158 37 121 124 0 8 5
pvpl 32 1547135 0 1525973 275 94 181 236 0 265 2
pmappl 216 3227 0 3138 6 0 6 6 0 8 0
extentpl 40 57 0 38 1 0 1 1 0 8 0
phpool 112 1577 0 697 35 9 26 35 0 8 0
ddb> machine ddbcpu 0
No such command
ddb> trace
end trace frame: 0x0, count: -1
ddb> machine ddbcpu 1
No such command
ddb> trace
end trace frame: 0x0, count: -1


---
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[syzbot]

syzbot has found a reproducer for the following issue on:

HEAD commit: a26a77a095e7 Use NULL instead of 0 for pointer.
git tree: openbsd
console output: https://syzkaller.appspot.com/x/log.txt?x=147327b9700000

kernel config: https://syzkaller.appspot.com/x/.config?x=fe55924c11e64b0a
dashboard link: https://syzkaller.appspot.com/bug?extid=d3e202981a9681e89eeb

syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17b32b49700000
C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12f9fa21700000

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+d3e202...@syzkaller.appspotmail.com

kernel: double fault trap, code=0

Stopped at kerntrap+0x1f: callq __sanitizer_cov_trace_pc+0x4
ddb>