Hello,
syzbot found the following issue on:
HEAD commit: 1dc30a6de584 last_addr no longer needs to be a global vari..
git tree: openbsd
console output:
https://syzkaller.appspot.com/x/log.txt?x=10691f1a580000
kernel config:
https://syzkaller.appspot.com/x/.config?x=7058272de1526588
dashboard link:
https://syzkaller.appspot.com/bug?extid=bfefe75352578cb7301a
Unfortunately, I don't have any reproducer for this issue yet.
Downloadable assets:
disk image:
https://storage.googleapis.com/syzbot-assets/49172e428804/disk-1dc30a6d.raw.xz
bsd.gdb:
https://storage.googleapis.com/syzbot-assets/45d9828a8a7e/bsd-1dc30a6d.gdb.xz
kernel image:
https://storage.googleapis.com/syzbot-assets/29fcf19c0ce4/kernel-1dc30a6d.xz
IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by:
syzbot+bfefe7...@syzkaller.appspotmail.com
uvm_fault(0xffffffff839809c0, 0x0, 0, 2) -> e
kernel: page fault trap, code=2
Stopped at km_free+0x191: movq $0,0(%rax)
TID PID UID PRFLAGS PFLAGS CPU COMMAND
*126777 43464 0 0x14000 0x200 0 systqmp
km_free(0,1000,ffffffff8351ec08,ffffffff8351ec20) at km_free+0x191 sys/uvm/uvm_km.c:672
pool_p_free(ffffffff83a0de20,fffffd8079199f90) at pool_p_free+0x1d0 sys/kern/subr_pool.c:1014
pool_gc_pages(0) at pool_gc_pages+0x357 sys/kern/subr_pool.c:1587
taskq_thread(ffffffff83822e10) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: 11
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
*cpu0: uvm_fault(0xffffffff839809c0, 0x0, 0, 2) -> e
ddb{0}> trace
km_free(0,1000,ffffffff8351ec08,ffffffff8351ec20) at km_free+0x191 sys/uvm/uvm_km.c:672
pool_p_free(ffffffff83a0de20,fffffd8079199f90) at pool_p_free+0x1d0 sys/kern/subr_pool.c:1014
pool_gc_pages(0) at pool_gc_pages+0x357 sys/kern/subr_pool.c:1587
taskq_thread(ffffffff83822e10) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: -4
ddb{0}> show registers
rdi 0x1000 __ALIGN_SIZE
rsi 0x28000000
rbp 0xffff80002a20a6e0
rbx 0xffffffff8351ec08 kv_page
rdx 0
rcx 0xffff8000ffffe000
rax 0
r8 0xffffffffffffffff
r9 0
r10 0xed06b602bbc5f718
r11 0xd07acfcc6183665a
r12 0x1000 __ALIGN_SIZE
r13 0
r14 0x1000 __ALIGN_SIZE
r15 0x28000000000
rip 0xffffffff8159ac21 km_free+0x191
cs 0x8
rflags 0x10246 __ALIGN_SIZE+0xf246
rsp 0xffff80002a20a670
ss 0x10
km_free+0x191: movq $0,0(%rax)
ddb{0}> show proc
PROC (systqmp) tid=126777 pid=43464 tcnt=1 stat=onproc
flags process=14000<NOZOMBIE,SYSTEM> proc=200<SYSTEM>
runpri=32, usrpri=51, slppri=32, nice=20
wchan=0x0, wmesg=, ps_single=0x0 scnt=0 ecnt=0
forw=0xffffffffffffffff, list=0xffff8000ffffe298,0xffff8000ffffe540
process=0xffff8000ffff8e70 user=0xffff80002a205000, vmspace=0xffffffff839809c0
estcpu=1, cpticks=2, pctcpu=0.0, user=0, sys=0, intr=0
ddb{0}> ps
PID TID PPID UID S FLAGS WAIT COMMAND
79616 186634 14234 60929 3 0x90 nanoslp syz-executor
79616 309851 14234 60929 3 0x4000090 kqsel syz-executor
79616 429950 14234 60929 3 0x4000090 kqsel syz-executor
79616 332401 14234 60929 3 0x4000090 fsleep syz-executor
14234 211803 86853 0 2 0x2 syz-executor
29878 380137 86853 0 3 0x82 piperd syz-executor
46119 196984 1 0 3 0x100083 ttyopn getty
15881 158229 86853 0 3 0x82 piperd syz-executor
30421 45122 86853 0 3 0x82 piperd syz-executor
7396 377777 86853 0 3 0x82 piperd syz-executor
18399 495959 86853 0 3 0x82 nanoslp syz-executor
45541 244473 86853 0 3 0x82 piperd syz-executor
86853 240987 51327 0 3 0x82 nanoslp syz-executor
51327 330809 47790 0 3 0x10008a sigsusp ksh
47790 226411 50321 0 3 0x98 kqread sshd-session
50321 112822 69444 0 3 0x92 kqread sshd-session
69444 200080 1 0 3 0x88 kqread sshd
75158 275260 24949 74 3 0x1100092 bpf pflogd
24949 415801 1 0 3 0x80 sbwait pflogd
11884 471082 97753 73 3 0x1100090 kqread syslogd
97753 246499 1 0 3 0x100082 sbwait syslogd
49272 313466 1 0 3 0x100080 kqread resolvd
21844 406100 24376 77 3 0x100092 kqread dhcpleased
17783 131687 24376 77 3 0x100092 kqread dhcpleased
24376 27828 1 0 3 0x80 kqread dhcpleased
8241 391178 0 0 3 0x14200 bored smr
5102 200716 0 0 3 0x14200 pgzero zerothread
40947 12750 0 0 3 0x14200 aiodoned aiodoned
32568 349607 0 0 3 0x14200 syncer update
83336 222010 0 0 3 0x14200 cleaner cleaner
40929 516323 0 0 3 0x14200 reaper reaper
41273 238396 0 0 3 0x14200 pgdaemon pagedaemon
97881 483722 0 0 3 0x14200 bored viomb
68374 376666 0 0 3 0x40014200 acpi0 acpi0
26762 21329 0 0 7 0x40014200 idle1
39256 165824 0 0 3 0x14200 bored softnet1
93262 344362 0 0 3 0x14200 bored softnet0
*43464 126777 0 0 7 0x14200 systqmp
33493 400766 0 0 3 0x14200 bored systq
43560 282190 0 0 3 0x14200 tmoslp softclockmp
88069 3984 0 0 3 0x40014200 tmoslp softclock
59031 8299 0 0 3 0x40014200 idle0
1 26529 0 0 3 0x80082 wait init
0 0 -1 0 3 0x10010200 scheduler swapper
ddb{0}> show all locks
Process 43464 (systqmp) thread 0xffff8000ffffe000 (126777)
shared rwlock pools r = 0 (0xffffffff837ec348)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 rw_do_enter_read+0x3e8 sys/kern/kern_rwlock.c:413
#2 pool_gc_pages+0x2e sys/kern/subr_pool.c:1564
#3 taskq_thread+0x157 sys/kern/kern_task.c:446
#4 proc_trampoline+0x10
shared rwlock systqmp r = 0 (0xffffffff83822e88)
#0 witness_lock+0x5f1 stacktrace_save sys/sys/stacktrace.h:37 [inline]
#0 witness_lock+0x5f1 sys/kern/subr_witness.c:1160
#1 taskq_thread+0x12a sys/kern/kern_task.c:442
#2 proc_trampoline+0x10
ddb{0}> show malloc
Type InUse MemUse HighUse Limit Requests Type Lim
devbuf 11096 12101K 14165K 166960K 14721 0
pcb 17 19K 24K 166960K 282 0
rtable 176 10K 10K 166960K 685 0
pf 37 18K 82K 166960K 180 0
ifaddr 33 5K 7K 166960K 126 0
ifgroup 55 2K 2K 166960K 191 0
sysctl 4 1K 9K 166960K 12 0
counters 70 37K 38K 166960K 336 0
ioctlops 0 0K 4K 166960K 1936 0
iov 0 0K 24K 166960K 71 0
mount 1 1K 1K 166960K 1 0
log 0 0K 0K 166960K 4 0
vnodes 1514 95K 96K 166960K 2716 0
UFS quota 1 32K 32K 166960K 1 0
UFS mount 5 36K 36K 166960K 5 0
shm 2 1K 5K 166960K 11 0
VM map 2 1K 1K 166960K 2 0
sem 12 0K 0K 166960K 165 0
dirhash 12 2K 2K 166960K 24 0
ACPI 1692 195K 286K 166960K 12470 0
file desc 11 37K 106K 166960K 1129 0
sigio 0 0K 0K 166960K 60 0
proc 72 115K 163K 166960K 795 0
subproc 63 3K 4K 166960K 126 0
NFS srvsock 1 0K 0K 166960K 1 0
NFS daemon 1 16K 16K 166960K 1 0
ip_moptions 0 0K 0K 166960K 327 0
in_multi 61 4K 7K 166960K 225 0
ether_multi 1 0K 0K 166960K 9 0
mrt 1 0K 0K 166960K 8 0
ISOFS mount 1 32K 32K 166960K 1 0
MSDOSFS mount 1 16K 16K 166960K 1 0
ttys 229 1023K 1023K 166960K 229 0
exec 0 0K 1K 166960K 600 0
fusefs mount 1 32K 32K 166960K 1 0
tdb 3 0K 0K 166960K 3 0
VM swap 8 62K 64K 166960K 10 0
UVM amap 195 149K 173K 166960K 11681 0
UVM aobj 88 9K 9K 166960K 93 0
pinsyscall 36 72K 104K 166960K 2406 0
memdesc 1 4K 4K 166960K 1 0
crypto data 1 1K 1K 166960K 1 0
ip6_options 0 0K 1K 166960K 83 0
NDP 12 0K 2K 166960K 90 0
temp 67 8676K 8798K 166960K 41882 0
kqueue 15 22K 32K 166960K 215 0
SYN cache 2 16K 16K 166960K 2 0
ddb{0}> show all pools
Name Size Requests Fail Releases Pgreq Pgrel Npage Hiwat Minpg Maxpg Idle
plcache 128 26 0 0 1 0 1 1 0 8 0
rtpcb 120 215 0 212 3 2 1 3 0 8 0
rtentry 176 201 0 140 6 1 5 6 0 8 0
unpcb 144 633 0 615 6 4 2 4 0 8 1
syncache 336 4 0 4 2 2 0 1 0 8 0
tcpqe 32 1 0 1 1 1 0 1 0 8 0
tcpcb 736 269 0 265 4 3 1 4 0 8 0
arp 136 32 0 21 1 0 1 1 0 8 0
inpcb 328 1320 0 1313 22 14 8 13 0 8 7
nd6 152 43 0 31 1 0 1 1 0 8 0
pkpcb 40 4 0 4 3 2 1 1 0 8 1
kcovpl 48 14 0 7 1 0 1 1 0 8 0
mppekey 1024 1 0 1 1 1 0 1 0 8 0
ppxss 1192 117 0 117 1 0 1 1 0 8 1
pppxif 1504 4 0 4 2 2 0 1 0 8 0
pfstscr 40 1 0 1 1 1 0 1 0 8 0
pffrag 232 15 0 0 1 0 1 1 0 482 0
pffrnode 88 14 0 0 1 0 1 1 0 8 0
pffrent 40 18 0 3 1 0 1 1 0 8 0
pfosfp 40 1428 0 1005 5 0 5 5 0 8 0
pfosfpen 112 1428 0 714 21 0 21 21 0 8 0
pfrktable 1344 1 0 1 1 1 0 1 0 8 0
pfstitem 24 66 0 22 1 0 1 1 0 8 0
pfstkey 128 70 0 26 2 0 2 2 0 8 0
pfstate 448 68 0 24 5 0 5 5 0 8 0
pfrule 1344 31 0 25 2 1 1 2 0 8 0
rttmr 136 2 0 2 1 1 0 1 0 8 0
art_heap8 4096 4 0 0 4 0 4 4 0 8 0
art_heap4 256 895 0 619 32 11 21 29 0 8 1
art_table 40 899 0 619 5 0 5 5 0 8 0
art_node 32 198 0 143 1 0 1 1 0 8 0
sysvmsgpl 40 7 0 5 1 0 1 1 0 8 0
semapl 112 162 0 152 1 0 1 1 0 8 0
shmpl 112 88 0 4 3 0 3 3 0 8 0
dirhash 1024 26 0 9 3 0 3 3 0 8 0
dino2pl 256 3525 0 2014 96 0 96 96 0 8 0
ffsino 296 3525 0 2014 118 1 117 118 0 8 0
nchpl 144 5071 0 3353 65 0 65 65 0 8 0
rtmask 32 12 0 12 1 1 0 1 0 8 0
vnodes 216 4393 0 0 245 0 245 245 0 8 0
namei 1024 18755 0 18755 2 1 1 2 0 8 1
percpumem 16 183 0 133 1 0 1 1 0 8 0
vcpupl 3968 2 0 1 1 0 1 1 0 8 0
vmpool 848 2 0 1 1 0 1 1 0 8 0
kstatmem 264 124 0 94 3 0 3 3 0 8 0
scsiplug 72 4 0 4 1 1 0 1 0 8 0
scxspl 216 20253 0 20253 11 9 2 8 1 8 2
plimitpl 152 166 0 150 1 0 1 1 0 8 0
sigapl 424 1421 0 1380 7 1 6 7 0 8 0
knotepl 120 555 0 0 17 0 17 17 0 8 0
kqueuepl 224 425 0 412 6 5 1 5 0 8 0
pipepl 344 243 0 216 6 3 3 6 0 8 0
fdescpl 528 1398 0 1373 3 0 3 3 0 8 0
filepl 160 9889 0 9689 30 13 17 22 0 8 7
lockfpl 104 326 0 324 1 0 1 1 0 8 0
lockfspl 48 127 0 125 1 0 1 1 0 8 0
sessionpl 144 30 0 21 1 0 1 1 0 8 0
pgrppl 48 54 0 38 1 0 1 1 0 8 0
ucredpl 104 1824 0 1810 1 0 1 1 0 8 0
zombiepl 144 1381 0 1380 1 0 1 1 0 8 0
processpl 1232 1421 0 1380 6 2 4 5 0 8 0
procpl 664 2864 0 2820 6 0 6 6 0 8 0
sosppl 176 2 0 2 2 2 0 1 0 8 0
sockpl 752 2269 0 2241 37 27 10 25 0 8 6
mcl64k 65536 3 0 0 1 0 1 1 0 8 0
mcl16k 16384 3 0 0 1 0 1 1 0 8 0
mcl9k 9216 1 0 0 1 0 1 1 0 8 0
mcl8k 8192 2 0 0 1 0 1 1 0 8 0
mcl4k 4096 132 0 0 16 0 16 16 0 8 0
mcl2k 2048 51 0 0 6 0 6 6 0 8 0
mtagpl 96 97 0 0 3 0 3 3 0 8 0
mbufpl 256 1296 0 0 81 0 81 81 0 8 0
bufpl 280 10017 0 3881 439 0 439 439 0 8 0
anonpl 32 11066 0 0 90 0 90 90 0 246 0
amapchunkpl 152 38022 0 37686 34 8 26 30 0 158 6
amappl16 200 4340 0 4317 38 27 11 22 0 8 8
amappl15 192 4 0 4 2 2 0 1 0 8 0
amappl14 184 4 0 4 1 1 0 1 0 8 0
amappl13 176 516 0 515 1 0 1 1 0 8 0
amappl12 168 1791 0 1755 3 0 3 3 0 8 0
amappl11 160 4 0 4 1 1 0 1 0 8 0
amappl10 152 48 0 34 1 0 1 1 0 8 0
amappl9 144 290 0 289 2 1 1 1 0 8 0
amappl8 136 30 0 28 1 0 1 1 0 8 0
amappl7 128 102 0 101 1 0 1 1 0 8 0
amappl6 120 359 0 344 1 0 1 1 0 8 0
amappl5 112 79 0 68 1 0 1 1 0 8 0
amappl4 104 450 0 420 1 0 1 1 0 8 0
amappl3 96 7538 0 7465 5 1 4 4 0 8 0
amappl2 88 575 0 515 2 0 2 2 0 8 0
amappl1 80 13539 0 12969 14 1 13 14 0 8 0
amappl 88 10717 0 10598 5 0 5 5 0 92 0
uvmvnodes 80 137 0 0 3 0 3 3 0 8 0
dma4096 4096 1 0 1 1 1 0 1 0 8 0
dma1024 1024 2 0 1 1 0 1 1 0 8 0
dma256 256 6 0 6 1 1 0 1 0 8 0
dma128 128 254 0 254 2 2 0 1 0 8 0
dma64 64 7 0 7 2 2 0 1 0 8 0
dma32 32 7 0 7 1 1 0 1 0 8 0
dma16 16 19 0 18 1 0 1 1 0 8 0
aobjpl 72 92 0 5 2 0 2 2 0 8 0
uaddrrnd 24 1398 0 1373 1 0 1 1 0 8 0
uaddrbest 32 2 0 0 1 0 1 1 0 8 0
uaddr 24 1398 0 1373 1 0 1 1 0 8 0
vmmpekpl 168 12267 0 12215 3 0 3 3 0 8 0
vmmpepl 168 93372 0 91763 109 12 97 105 0 357 11
vmsppl 488 1397 0 1373 6 1 5 5 0 8 0
rwobjpl 80 26307 0 25228 32 4 28 31 0 8 0
pdppl 4096 2808 0 2749 123 48 75 86 0 8 16
pvpl 32 20349 0 0 164 0 164 164 0 265 0
pmappl 256 1399 0 1374 3 0 3 3 0 8 0
extentpl 40 45 0 27 1 0 1 1 0 8 0
phpool 112 384 0 68 10 0 10 10 0 8 0
ddb{0}> machine ddbcpu 0
Invalid cpu 0
ddb{0}> trace
km_free(0,1000,ffffffff8351ec08,ffffffff8351ec20) at km_free+0x191 sys/uvm/uvm_km.c:672
pool_p_free(ffffffff83a0de20,fffffd8079199f90) at pool_p_free+0x1d0 sys/kern/subr_pool.c:1014
pool_gc_pages(0) at pool_gc_pages+0x357 sys/kern/subr_pool.c:1587
taskq_thread(ffffffff83822e10) at taskq_thread+0x157 sys/kern/kern_task.c:446
end trace frame: 0x0, count: -4
ddb{0}> machine ddbcpu 1
Stopped at x86_ipi_db+0x27: addq $0x8,%rsp
x86_ipi_db(ffff8000299ddff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
acpicpu_idle() at acpicpu_idle+0x457 sys/dev/acpi/acpicpu_x86.c:1224
sched_idle(ffff8000299ddff0) at sched_idle+0x391 sys/kern/kern_sched.c:191
end trace frame: 0x0, count: 10
ddb{1}> trace
x86_ipi_db(ffff8000299ddff0) at x86_ipi_db+0x27 sys/arch/amd64/amd64/db_interface.c:394
x86_ipi_handler() at x86_ipi_handler+0xd9 sys/arch/amd64/amd64/ipi.c:106
Xresume_lapic_ipi() at Xresume_lapic_ipi+0x27
acpicpu_idle() at acpicpu_idle+0x457 sys/dev/acpi/acpicpu_x86.c:1224
sched_idle(ffff8000299ddff0) at sched_idle+0x391 sys/kern/kern_sched.c:191
end trace frame: 0x0, count: -5
---
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