Re: [PATCH] Kprobes i386 fix for mark ro data

From: Patrick Andrieux
Date: Mon Jun 11 2007 - 14:36:53 EST


Hi,

This patch fixed my problem. I re-enabled CONFIG_DEBUG_RODATA and I
don't have seg fault with or without your DCCP patches. Inserting
`dccp_probe` or `tcp_probe`module doesn't cause any troubles.

Patrick.


On 10/06/07, Ian McDonald <ian.mcdonald@xxxxxxxxxxx> wrote:
On 6/7/07, S. P. Prasanna <prasanna@xxxxxxxxxx> wrote:
> > >It faulted when it tried to write the breakpoint instruction into the
> > >running kernel's executable code. Apparently the kernel code is now marked
> > >read-only?
> > >
> > >
> > Yes it would appear to be the case as user has CONFIG_DEBUG_RODATA
> > set. Patrick - can you turn this off and retest? It's under Kernel
> > Hacking, Write protect kernel read only data structures.
> >
>
> Ian,
>
> Please find the fix as suggested by Andi Kleen
> for the above stated problem.
>
> Thanks
> Prasanna
>
>
I went to test the fix and first of all went to replicate the problem.
My build has CONFIG_DEBUG_RODATA set but the problem does not occur
without the patch. Should I be concerned about this and raise a bug
for that as I would think that means there is a problem that the read
only protection isn't working (this is off Linus' tree synced
tonight).

Patrick - can you test whether this patch fixes your problem? You said
disabling CONFIG_DEBUG_RODATA fixed your problem but can you try
re-enabling and testing this patch?

Ian
--
Web: http://wand.net.nz/~iam4/
Blog: http://iansblog.jandi.co.nz
WAND Network Research Group

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