Re: [PATCH] Move some more structures into "mostly_readonly"

From: Arjan van de Ven
Date: Wed Jun 08 2005 - 05:41:08 EST


On Wed, 2005-06-08 at 12:20 +0200, JÃrn Engel wrote:
> On Wed, 8 June 2005 12:07:25 +0200, Arjan van de Ven wrote:
> > On Wed, 2005-06-08 at 12:00 +0200, JÃrn Engel wrote:
> > > On Tue, 7 June 2005 17:31:19 -0400, Brian Gerst wrote:
> > > >
> > > > It doesn't really matter. .rodata isn't actually mapped read-only.
> > > > Doing so would break up the large pages used to map the kernel.
> > >
> > > Can you confirm that for every architecture? Or just i386?
> >
> > does it matter? it's supposed to be read only, only sometimes that's not
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > enforced unfortunately.
>
> I agree. What I don't agree with is "It doesn't really matter" - not
> after debugging the occasional memory corruptions.

I agree, and it would be very useful to have a debug option in the
kernel that say checksums rodata (and probably the kernel text which is
also read only) periodically and raises an alarm if the checksum
changes.

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