Hi All!
It is fully reproductable under 2.6.22.15, 2.6.23.13 (all tainted and

not tainted [4 different kernel] ) and 2 different PC:
[BUG] skge 0000:02:05: read data parity error

[BUG] skge 0000:02:05: read data parity error
steps:

1. login as root

2. start mc

3. cd /sys/bus/pci/drivers/skge/0000:02:05.0

4. press F3 (mcview) on resource0

5. the system hang up, without panic or bug ... only this message

printed 2x: [BUG] skge 0000:02:05: read data parity error
when I used cat for show what is in file , then bocome this message:

 cat: resource0: Input/output error

but the permissions is:

 -rw------- 1 root root 16384 2008-01-14 20:36 resource0
when I used mcview for show whats in file, then the system hang up,

and not reagiert neither for SysRQ-s, only for hard reset.
-----------
PC1.:

00:00.0 Host bridge [0600]: Intel Corporation 945G/GZ/P/PL Express

Memory Controller Hub [8086:2770] (rev 02)

00:01.0 PCI bridge [0604]: Intel Corporation 945G/GZ/P/PL Express PCI

Express Root Port [8086:2771] (rev 02)

00:1b.0 Audio device [0403]: Intel Corporation 82801G (ICH7 Family)

High Definition Audio Controller [8086:27d8] (rev 01)

00:1d.0 USB Controller [0c03]: Intel Corporation 82801G (ICH7 Family)

USB UHCI #1 [8086:27c8] (rev 01)

00:1d.1 USB Controller [0c03]: Intel Corporation 82801G (ICH7 Family)

USB UHCI #2 [8086:27c9] (rev 01)

00:1d.2 USB Controller [0c03]: Intel Corporation 82801G (ICH7 Family)

USB UHCI #3 [8086:27ca] (rev 01)

00:1d.3 USB Controller [0c03]: Intel Corporation 82801G (ICH7 Family)

USB UHCI #4 [8086:27cb] (rev 01)

00:1d.7 USB Controller [0c03]: Intel Corporation 82801G (ICH7 Family)

USB2 EHCI Controller [8086:27cc] (rev 01)

00:1e.0 PCI bridge [0604]: Intel Corporation 82801 PCI Bridge

[8086:244e] (rev e1)

00:1f.0 ISA bridge [0601]: Intel Corporation 82801GB/GR (ICH7 Family)

LPC Interface Bridge [8086:27b8] (rev 01)

00:1f.2 IDE interface [0101]: Intel Corporation 82801GB/GR/GH (ICH7

Family) Serial ATA Storage Controller IDE [8086:27c0] (rev 01)

00:1f....
[ message continues ]

On Mon, 14 Jan 2008 20:57:49 +0100
This is not a bug.
The hardware has some debug registers that if accessed cause a read

back to the host. Since this can point anywhere, it will cause errors

or system hang.
The point is don't do it.
--

Stephen Hemminger <stephen.hemminger@vyatta.com>

--

Is it really a good idea that _reading_ files under /sys can kill your

machine?
That sounds like a huge trap for people debugging their machine (or e.g.

forgetting to exclude /sys from their backup).
cu

Adrian
-- 
       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed
--

I think, it is a potential security breakpoint, when applications with

root permission its read, then a machine is freezed, or only i thin

it's?
--

Thanks,

Oliver

--

I'm sorry, I don't quite understand what you are trying to say here.

--

huh, sorry, it's typo and i'm not learn english,  only myself ... and

my spelling is very bad, sorry
--

Thanks,

Oliver

--

When you are root there are infinite ways to kill your machine, so 
cu

Adrian
-- 
       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed
--

Yes, i know, but when some application or daemons read some file with

running root privileges, then ...
--

Thanks,

Oliver

--

It might be a bug in the application.
But there are worse things than crashing your machine (e.g. getting your

/etc/shadow) that can happen when someone with bad intentions can read 
cu

Adrian
-- 
       "Is there not promise of rain?" Ling Tan asked suddenly out

        of the darkness. There had been need of rain for many days.

       "Only a promise," Lao Er said.

                                       Pearl S. Buck - Dragon Seed
--

I "tested" other devices resources file, and only with skge freezed

the system. from this think, that is skge driver bug
--

Thanks,

Oliver

--

On Mon, 14 Jan 2008 22:58:51 +0100
Its a property of the hardware, and the current device model has

no way to stop it.  Other devices are worse and can die if you access

pci config space.
--

Stephen Hemminger <stephen.hemminger@vyatta.com>

--

It's always been that way, this is nothing new.
thanks,
greg k-h

--

No, but mmapping them as root and then doing bad things with that data

isn't recommended :)
Note that this is a special file, just like the ones in /proc, that

provide a mmap interface into the pci card's resource.  This is nothing

new...
thanks,
greg k-h

--