[lug] kernel paging request errors

[rm at mamma.varadinet.de]

On Tue, Mar 27, 2001 at 07:17:54AM -0700, D. Stimits wrote:
> dan radom wrote:
> > 
> > hi,
> > 
> > every 10 minutes i get the following error in my logs...
> > 
> > Mar 26 15:50:01 mars kernel: Unable to handle kernel paging request at virtual address 5760c297
> 
> Does the address "5760c297" consistently appear? Is it always that
> address? If and only if it is that address at all times, do you have
> more than one DIMM or other memory type that you can swap locations with
> (if so, physically swap memory and see if the address changes or the
> machine has other problems that then show up)?
> 

Hmm, the error messages  is from the file fault.c in the architecture
dependend parts of your kernel sources <arch>/mm/fault.c in the
function 'do_page_fault(...' This is a central function for the
memory manaegment. The comment here is:



/* ops. The kernel tried to access some bad page. We'll have to
 * terminate things with extreme prejudice.
 *
 * First we check if it was the bootup rw-test, though..
 */

which of course can mean a lot of things. It _could_ mean bad RAM
but i also could mean _non_existing_ RAM. I had a similar problem
recently with a server that had plenty of RAM. Unfortunately the
super-new BIOS couldn't handle it. The box would boot up with a
random amount of memory available. Somtimes the whole RAM was there,
sometimes only 55Mb ... Adding an expicit mem=521M to the kernel
startup parameters fixed it. What does 'free' show?
BTW, the address in the error report won't be the same (exept in a
very rare coincidence); as the message states, this is a _virtual_
address, not the hardware address.

 Ralf

> D. Stimits, stimits at idcomm.com