kernel panic - BUG in sched.c using SMB protocol

[kaleidoscopeit]

Recently I have got a VIA Epia mini-itx motherboard.

Randomly it drop in kernel panic, but when many connections from the clients are established,
kernel panic becames more frequent and the machine becomes useless.

My attempts were as follows :

- Kernels releases from 2.6.16 to 2.6.24 ---> No difference
- Kernel option "ACPI=off" ---> Good improvement
- Either on Debian and Ubuntu Server ---> No difference
- Blacklist unnecessary modules ---> Seems a little improvement
- Two different memory bank with long memory tests performed ---> No difference
- MS Windows with hardware stress sofware ---> No problems

After a period of observation and some empiric tests I got the impression that the smb protocol is involved.

My interesting empiric tests were as follow :

with "socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=8192 SO_SNDBUF=8192" in smb.conf

  Kernel panic always happens :

  - When I put a directory with many files in a samba share using Ubuntu or Windows
  - When I copy a single file beginning from 10 Mb

  Kernel panic doesn't happens :

  - When I put a file or a directory with many files with ssh protocol using Nautilus
  - When I copy a file filled with zeroes using smb protocol

Without "socket options = TCP_NODELAY IPTOS_LOWDELAY SO_RCVBUF=8192 SO_SNDBUF=8192" in smb.conf

  Kernel panic always happens :

  - When I copy directly from another PC to the Via Epia using smb protocol a file or a directory through third computer
    with Ubuntu, with Windows no problem.

  Kernel panic rarely happens :

  - during normal use

Kernel Panic snapshot attached

My lspci output

00:00.0 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.1 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.2 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.3 Host bridge: VIA Technologies, Inc. PT890 Host Bridge
00:00.4 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:00.7 Host bridge: VIA Technologies, Inc. CN700/VN800/P4M800CE/Pro Host Bridge
00:01.0 PCI bridge: VIA Technologies, Inc. VT8237 PCI Bridge
00:09.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8110SC/8169SC Gigabit Ethernet (rev 10)
00:0b.0 Ethernet controller: Realtek Semiconductor Co., Ltd. RTL-8110SC/8169SC Gigabit Ethernet (rev 10)
00:0f.0 IDE interface: VIA Technologies, Inc. VT82C586A/B/VT82C686/A/B/VT823x/A/C PIPC Bus Master IDE (rev 06)
00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.1 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.2 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.3 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 81)
00:10.4 USB Controller: VIA Technologies, Inc. USB 2.0 (rev 86)
00:11.0 ISA bridge: VIA Technologies, Inc. VT8237 ISA bridge [KT600/K8T800/K8T890 South]
01:00.0 VGA compatible controller: VIA Technologies, Inc. UniChrome Pro IGP (rev 01)

My cat /proc/cpuinfo

processor : 0
vendor_id : CentaurHauls
cpu family : 6
model : 10
model name : VIA Esther processor 1500MHz
stepping : 9
cpu MHz : 1500.099
cache size : 128 KB
fdiv_bug : no
hlt_bug : no
f00f_bug : no
coma_bug : no
fpu : yes
fpu_exception : yes
cpuid level : 1
wp : yes
flags : fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge cmov pat clflush acpi mmx fxsr sse sse2 tm nx up pni est tm2 rng rng_en ace ace_en ace2 ace2_en phe phe_en pmm pmm_en
bogomips : 3001.85
clflush size : 64

My lsmod

Module Size Used by
ipv6 272804 12
iptable_filter 3840 0
ip_tables 14820 1 iptable_filter
x_tables 16132 1 ip_tables
aes_i586 33536 0
dm_crypt 15236 0
dm_mod 62532 1 dm_crypt
lp 12324 0
loop 19076 0
evdev 12928 0
parport_pc 36644 1
parport 37704 2 lp,parport_pc
serio_raw 7940 0
psmouse 40208 0
i2c_viapro 9876 0
i2c_core 24832 1 i2c_viapro
pcspkr 4224 0
shpchp 34452 0
pci_hotplug 30880 1 shpchp
via_agp 11136 1
agpgart 34760 1 via_agp
reiserfs 238720 5
usb_storage 73408 0
libusual 18980 1 usb_storage
sg 36496 0
sd_mod 30720 7
pata_via 13316 6
ehci_hcd 38412 0
uhci_hcd 27152 0
ata_generic 8324 0
pata_acpi 8320 0
usbcore 146028 5 usb_storage,libusual,ehci_hcd,uhci_hcd
libata 159344 3 pata_via,ata_generic,pata_acpi
scsi_mod 151180 4 usb_storage,sg,sd_mod,libata
r8169 32772 0
fuse 50580 1
vesafb 8964 1
fbcon 42656 70
tileblit 3456 1 fbcon
font 9472 1 fbcon
bitblit 6784 1 fbcon
softcursor 3072 1 bitblit

[Leann Ogasawara (leannogasawara)]

The Ubuntu Kernel Team is planning to move to the 2.6.27 kernel for the upcoming Intrepid Ibex 8.10 release. As a result, the kernel team would appreciate it if you could please test this newer 2.6.27 Ubuntu kernel. There are one of two ways you should be able to test:

1) If you are comfortable installing packages on your own, the linux-image-2.6.27-* package is currently available for you to install and test.

--or--

2) The upcoming Alpha5 for Intrepid Ibex 8.10 will contain this newer 2.6.27 Ubuntu kernel. Alpha5 is set to be released Thursday Sept 4. Please watch http://www.ubuntu.com/testing for Alpha5 to be announced. You should then be able to test via a LiveCD.

Please let us know immediately if this newer 2.6.27 kernel resolves the bug reported here or if the issue remains. More importantly, please open a new bug report for each new bug/regression introduced by the 2.6.27 kernel and tag the bug report with 'linux-2.6.27'. Also, please specifically note if the issue does or does not appear in the 2.6.26 kernel. Thanks again, we really appreicate your help and feedback.

[Ralph Janke (txwikinger)]

The Intrepid Ibex 8.10 Beta release was most recently announced - http://www.ubuntu.com/testing/intrepid/beta . It contains the 2.6.27 Ubuntu kernel. It would be great if you could test and verify if this is still an issue. The status is being set to Incomplete until we receive further feedback. Thanks.

[kaleidoscopeit (jaater)]

Seem to be solved!

After I move the PC in another room, without any other pc running close to it no more kernel panics are issued.

I had verified the overheating of the components, but everything was okay.

I believe that this problem has occurred as a result of a lack of immunity to electro-magnetic radiation of the VIA Epia mini-itx motherboard.

Now this mini server is up for two months without any kernel panic.

[Leann Ogasawara (leannogasawara)]

THanks for the note, I'll go ahead and close this bug.

[Launchpad Janitor (janitor)]

Per a decision made by the Ubuntu Kernel Team, bugs will longer be assigned to the ubuntu-kernel-team in Launchpad as part of the bug triage process. The ubuntu-kernel-team is being unassigned from this bug report. Refer to https://wiki.ubuntu.com/KernelTeamBugPolicies for more information. Thanks.