[techtalk] free_one_pmd: bad directory entry 00000020

Shawn Strout sstrout at nc.rr.com
Sat Jan 20 19:26:22 EST 2001


> -----Original Message-----
> From: techtalk-admin at linuxchix.org
> [mailto:techtalk-admin at linuxchix.org]On Behalf Of Jeff Dike
> Sent: Friday, January 19, 2001 2:03 PM
> To: Shawn Strout
> Cc: techtalk
> Subject: Re: [techtalk] free_one_pmd: bad directory entry 00000020
>
>
> > free_one_pmd: bad directory entry 00000020
> > Is this a kernel error and how severe is it? Should I worry?
>
> This looks like a NULL which has had a one-bit error in it.  If
> so, you have
> some flaky memory.
>
> It could crash your system if it happens in the right place.  The
> error above
> happened in a page table, which pretty serious.  If it had
> switched a bit in a
> non-zero pmd, you could have had some pretty serious data corruption.

Could you please be more specific? IANAKH (I Am Not A Kernel Hacker). What
is a NULL in this context and what kind of "directory" is it? I thought it
referred to the disk, but it sounds like you're saying it's a RAM problem.

It is happening frequently - sometimes several in a second and sometimes 10
minutes between. It is always in the same address, 00000020.

Do you have any suggestions on how to debug or correct it? Should I start
pulling RAM out of my machine and see if goes away?

Are you sure this is related to memory, or could there be some other cause?

Thanks,
Shawn





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