Re: KVM induced panic on 2.6.38[2367] & 2.6.39

Brad Campbell
2011-06-07T03:33:55Z

On 07/06/11 04:10, Bart De Schuymer wrote:
> Hi Brad,
>
> This has probably nothing to do with ebtables, so please rmmod in case
> it's loaded.
> A few questions I didn't directly see an answer to in the threads I
> scanned...
> I'm assuming you actually use the bridging firewall functionality. So,
> what iptables modules do you use? Can you reduce your iptables rules to
> a core that triggers the bug?
> Or does it get triggered even with an empty set of firewall rules?
> Are you using a stock .35 kernel or is it patched?
> Is this something I can trigger on a poor guy's laptop or does it
> require specialized hardware (I'm catching up on qemu/kvm...)?

Not specialised hardware as such, I've just not been able to reproduce
it outside of this specific operating scenario.

I can't trigger it with empty firewall rules as it relies on a DNAT to
occur. If I try it directly to the internal IP address (as I have to
without netfilter loaded) then of course nothing fails.

It's a pain in the bum as a fault, but it's one I can easily reproduce
as long as I use the same set of circumstances.

I'll try using 3.0-rc2 (current git) tonight, and if I can reproduce it
on that then I'll attempt to pare down the IPTABLES rules to a bare minimum.

It is nothing to do with ebtables as I don't compile it. I'm not really
sure about "bridging firewall" functionality. I just use a couple of
hand coded bash scripts to set the tables up.

brad@srv:~$ lsmod
Module Size Used by
xt_iprange 1637 1
xt_DSCP 2077 2
xt_length 1216 1
xt_CLASSIFY 1091 26
sch_sfq 6681 4
xt_CHECKSUM 1229 2 brad@srv:~$ lsmod
Module Size Used by
xt_iprange 1637 1
xt_DSCP 2077 2
xt_length 1216 1
xt_CLASSIFY 1091 26
sch_sfq 6681 4
xt_CHECKSUM 1229 2
ipt_REJECT 2277 1
ipt_MASQUERADE 1759 7
ipt_REDIRECT 1133 1
xt_recent 8223 2
xt_state 1226 5
iptable_nat 3993 1
nf_nat 16773 3 ipt_MASQUERADE,ipt_REDIRECT,iptable_nat
nf_conntrack_ipv4 11868 8 iptable_nat,nf_nat
nf_conntrack 60962 5
ipt_MASQUERADE,xt_state,iptable_nat,nf_nat,nf_conntrack_ipv4
nf_defrag_ipv4 1417 1 nf_conntrack_ipv4
xt_TCPMSS 2567 2
xt_tcpmss 1469 0
xt_tcpudp 2467 56
iptable_mangle 1487 1
pppoe 9574 2
pppox 2188 1 pppoe
iptable_filter 1442 1
ip_tables 16762 3 iptable_nat,iptable_mangle,iptable_filter
x_tables 20462 17
xt_iprange,xt_DSCP,xt_length,xt_CLASSIFY,xt_CHECKSUM,ipt_REJECT,ipt_MASQUERADE,ipt_REDIRECT,xt_recent,xt_state,iptable_nat,xt_TCPMSS,xt_tcpmss,xt_tcpudp,iptable_mangle,iptable_filter,ip_tables
ppp_generic 24243 6 pppoe,pppox
slhc 5293 1 ppp_generic
cls_u32 6468 6
sch_htb 14432 2
deflate 1937 0
zlib_deflate 21228 1 deflate
des_generic 16135 0
cbc 2721 0
ecb 1975 0
crypto_blkcipher 13645 2 cbc,ecb
sha1_generic 2095 0
md5 4001 0
hmac 2977 0
crypto_hash 14519 3 sha1_generic,md5,hmac
cryptomgr 2636 0
aead 6137 1 cryptomgr
crypto_algapi 15289 9
deflate,des_generic,cbc,ecb,crypto_blkcipher,hmac,crypto_hash,cryptomgr,aead
af_key 27372 0
fuse 66747 1
w83627ehf 32052 0
hwmon_vid 2867 1 w83627ehf
vhost_net 16802 6
powernow_k8 12932 0
mperf 1263 1 powernow_k8
kvm_amd 53431 24
kvm 235155 1 kvm_amd
pl2303 12732 1
xhci_hcd 62865 0
i2c_piix4 8391 0
k10temp 3183 0
usbserial 34452 3 pl2303
usb_storage 37887 1
usb_libusual 10999 1 usb_storage
ohci_hcd 18105 0
ehci_hcd 33641 0
ahci 20748 4
usbcore 130936 7
pl2303,xhci_hcd,usbserial,usb_storage,usb_libusual,ohci_hcd,ehci_hcd
libahci 21202 1 ahci
sata_mv 26939 0
megaraid_sas 71659 14

Nat Table (external ip substituted for xxx.xxx.xxx.xxx)

Chain PREROUTING (policy ACCEPT 1761K packets, 152M bytes)
pkts bytes target prot opt in out source
destination
5 210 DNAT udp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 udp dpt:1195 to:192.168.253.199
6 252 DNAT udp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx udp dpt:1195 to:192.168.253.199
0 0 DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:25001 to:192.168.253.199:465
0 0 DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:25000 to:192.168.253.199:993
0 0 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:25001 to:192.168.253.199:465
0 0 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:25000 to:192.168.253.199:993
2 142 DNAT 47 -- ppp0 * 0.0.0.0/0
0.0.0.0/0 to:192.168.253.199
18 880 DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:1723 to:192.168.253.199
0 0 DNAT 47 -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx to:192.168.253.199
0 0 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:1723 to:192.168.253.199
2969 149K DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:443 to:192.168.253.198
20 1280 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:443 to:192.168.253.198
0 0 DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:3101 to:192.168.253.197
0 0 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:3101 to:192.168.253.197
0 0 DNAT tcp -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx tcp dpt:4101 to:192.168.253.197
44528 2718K REDIRECT tcp -- !ppp0 * 0.0.0.0/0
!192.168.0.0/16 tcp dpt:80 redir ports 8080
0 0 DNAT tcp -- * * 0.0.0.0/0
0.0.0.0/0 tcp dpt:3724 to:192.168.2.107
596K 33M DNAT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpts:2001:2030 to:10.99.99.2
1420K 119M DNAT udp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 udp dpts:2001:2030 to:10.99.99.2
7483 449K DNAT all -- !ppp0 * 0.0.0.0/0
xxx.xxx.xxx.xxx to:192.168.2.1

Mangle Table

Chain INPUT (policy ACCEPT 270K packets, 17M bytes)
pkts bytes target prot opt in out source
destination

Chain OUTPUT (policy ACCEPT 170K packets, 12M bytes)
pkts bytes target prot opt in out source
destination

Chain POSTROUTING (policy ACCEPT 2205K packets, 166M bytes)
pkts bytes target prot opt in out source
destination
0 0 MASQUERADE all -- * * 0.0.0.0/0
192.168.254.3
6 360 ACCEPT all -- * * 0.0.0.0/0
xxx.xxx.xxx.xxx
20424 2120K MASQUERADE all -- * ppp0 192.168.0.0/16
!192.168.0.0/16
0 0 MASQUERADE all -- * ppp0 10.0.0.0/24
0.0.0.0/0
3 204 MASQUERADE all -- * * 192.168.2.0/24
10.8.0.0/24
1418K 128M MASQUERADE all -- * * 10.99.99.0/24
0.0.0.0/0
68248 4095K MASQUERADE all -- * * 192.168.253.0/24
10.8.0.0/16
13305 2405K MASQUERADE all -- * * 192.168.253.0/24
!192.168.0.0/16

Chain PREROUTING (policy ACCEPT 278M packets, 293G bytes)
pkts bytes target prot opt in out source
destination
169 55528 CHECKSUM udp -- br1 * 0.0.0.0/0
0.0.0.0/0 udp dpt:67 CHECKSUM fill

Chain INPUT (policy ACCEPT 180M packets, 250G bytes)
pkts bytes target prot opt in out source
destination

Chain FORWARD (policy ACCEPT 98M packets, 44G bytes)
pkts bytes target prot opt in out source
destination

Chain OUTPUT (policy ACCEPT 155M packets, 180G bytes)
pkts bytes target prot opt in out source
destination

Chain POSTROUTING (policy ACCEPT 253M packets, 223G bytes)
pkts bytes target prot opt in out source
destination
165 54182 CHECKSUM udp -- * br1 0.0.0.0/0
0.0.0.0/0 udp spt:67 CHECKSUM fill
51 3712 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:53 CLASSIFY set 1:20
85274 6454K CLASSIFY udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp dpt:53 CLASSIFY set 1:20
187 257K CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp spt:81 CLASSIFY set 1:20
25M 1180M CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp flags:0x3F/0x10 state ESTABLISHED length 40:100
CLASSIFY set 1:15
728K 67M CLASSIFY icmp -- * ppp0 0.0.0.0/0
0.0.0.0/0 CLASSIFY set 1:15
231 23484 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:2401 CLASSIFY set 1:15
65636 5610K CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:22 CLASSIFY set 1:10
2018 315K CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp spt:22 CLASSIFY set 1:10
80 10092 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:3389 CLASSIFY set 1:10
26063 8910K CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:8080 CLASSIFY set 1:15
932K 131M CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:80 CLASSIFY set 1:15
3511 267K CLASSIFY udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp dpt:123 CLASSIFY set 1:10
0 0 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp spt:20 CLASSIFY set 1:15
3 180 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:20 CLASSIFY set 1:15
94058 38M CLASSIFY 47 -- * ppp0 0.0.0.0/0
0.0.0.0/0 CLASSIFY set 1:10
1086K 183M CLASSIFY udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp spt:1194 CLASSIFY set 1:10
1086K 183M TOS udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp spt:1194 TOS set 0x10/0x3f
48817 10M CLASSIFY udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp spt:1195 CLASSIFY set 1:10
48817 10M TOS udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp spt:1195 TOS set 0x10/0x3f
94058 38M CLASSIFY 47 -- * ppp0 0.0.0.0/0
0.0.0.0/0 CLASSIFY set 1:15
106 7207 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:1863 CLASSIFY set 1:15
188K 34M CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:443 CLASSIFY set 1:15
51541 3327K CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpts:6660:6669 CLASSIFY set 1:15
0 0 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp spts:2021:2030 CLASSIFY set 1:15
85 4944 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp dpt:19999 CLASSIFY set 1:15
208K 86M CLASSIFY udp -- * * 0.0.0.0/0
0.0.0.0/0 source IP range 192.168.2.80-192.168.2.120 CLASSIFY
set 1:10
0 0 CLASSIFY tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp spt:12345 CLASSIFY set 1:15
1 80 CLASSIFY udp -- * ppp0 0.0.0.0/0
0.0.0.0/0 udp spt:12345 CLASSIFY set 1:15

Default table

Chain INPUT (policy ACCEPT 176M packets, 247G bytes)
pkts bytes target prot opt in out source
destination
0 0 ACCEPT udp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 udp dpt:4569
1187K 582M ACCEPT udp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 udp dpt:1194
2 577 ACCEPT udp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 udp dpt:1195
28 1224 ACCEPT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:3389
230 12372 tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:22 state NEW recent: SET name: DEFAULT side:
source
3 180 DROP tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:22 state NEW recent: UPDATE seconds: 300
hit_count: 4 name: DEFAULT side: source
1750 143K ACCEPT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:22
3 144 ACCEPT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:113
120 6090 ACCEPT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:81
36094 29M ACCEPT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp dpt:25
1456K 1706M ACCEPT all -- ppp0 * 0.0.0.0/0
0.0.0.0/0 state RELATED,ESTABLISHED
31047 2334K REJECT tcp -- ppp0 * 0.0.0.0/0
0.0.0.0/0 tcp option=!2 reject-with tcp-reset
552K 60M ACCEPT all -- !ppp0 * 0.0.0.0/0
0.0.0.0/0 state NEW
13552 1207K ACCEPT icmp -- ppp0 * 0.0.0.0/0
0.0.0.0/0
5712 392K DROP all -- ppp0 * 0.0.0.0/0
0.0.0.0/0

Chain FORWARD (policy ACCEPT 98M packets, 44G bytes)
pkts bytes target prot opt in out source
destination
1207K 68M TCPMSS tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS clamp to PMTU

Chain OUTPUT (policy ACCEPT 155M packets, 180G bytes)
pkts bytes target prot opt in out source
destination
31675 1895K TCPMSS tcp -- * ppp0 0.0.0.0/0
0.0.0.0/0 tcp flags:0x06/0x02 TCPMSS clamp to PMTU

lsmod

ipt_REJECT 2277 1
ipt_MASQUERADE 1759 7
ipt_REDIRECT 1133 1
xt_recent 8223 2
xt_state 1226 5
iptable_nat 3993 1
nf_nat 16773 3 ipt_MASQUERADE,ipt_REDIRECT,iptable_nat
nf_conntrack_ipv4 11868 8 iptable_nat,nf_nat
nf_conntrack 60962 5
ipt_MASQUERADE,xt_state,iptable_nat,nf_nat,nf_conntrack_ipv4
nf_defrag_ipv4 1417 1 nf_conntrack_ipv4
xt_TCPMSS 2567 2
xt_tcpmss 1469 0
xt_tcpudp 2467 56
iptable_mangle 1487 1
pppoe 9574 2
pppox 2188 1 pppoe
iptable_filter 1442 1
ip_tables 16762 3 iptable_nat,iptable_mangle,iptable_filter
x_tables 20462 17
xt_iprange,xt_DSCP,xt_length,xt_CLASSIFY,xt_CHECKSUM,ipt_REJECT,ipt_MASQUERADE,ipt_REDIRECT,xt_recent,xt_state,iptable_nat,xt_TCPMSS,xt_tcpmss,xt_tcpudp,iptable_mangle,iptable_filter,ip_tables
ppp_generic 24243 6 pppoe,pppox
slhc 5293 1 ppp_generic
cls_u32 6468 6
sch_htb 14432 2
deflate 1937 0
zlib_deflate 21228 1 deflate
des_generic 16135 0
cbc 2721 0
ecb 1975 0
crypto_blkcipher 13645 2 cbc,ecb
sha1_generic 2095 0
md5 4001 0
hmac 2977 0
crypto_hash 14519 3 sha1_generic,md5,hmac
cryptomgr 2636 0
aead 6137 1 cryptomgr
crypto_algapi 15289 9
deflate,des_generic,cbc,ecb,crypto_blkcipher,hmac,crypto_hash,cryptomgr,aead
af_key 27372 0
fuse 66747 1
w83627ehf 32052 0
hwmon_vid 2867 1 w83627ehf
vhost_net 16802 6
powernow_k8 12932 0
mperf 1263 1 powernow_k8
kvm_amd 53431 24
kvm 235155 1 kvm_amd
pl2303 12732 1
xhci_hcd 62865 0
i2c_piix4 8391 0
k10temp 3183 0
usbserial 34452 3 pl2303
usb_storage 37887 1
usb_libusual 10999 1 usb_storage
ohci_hcd 18105 0
ehci_hcd 33641 0
ahci 20748 4
usbcore 130936 7
pl2303,xhci_hcd,usbserial,usb_storage,usb_libusual,ohci_hcd,ehci_hcd
libahci 21202 1 ahci
sata_mv 26939 0
megaraid_sas 71659 14