Re: [PATCH][2.5.47]Add exported valid_kernel_address()

Rusty Lynch (rusty@linux.co.intel.com)
Wed, 13 Nov 2002 14:30:32 -0800


To clarify further, I am talking about the sample driver I submitted earlier
at
http://marc.theaimsgroup.com/?l=linux-kernel&m=103721364225087&w=2

The patch implements a char device that enables arbitrary printk's to be
inserted at in arbitrary kernel addresses. It is used by writing strings of
the
form "0xADDRESS MESSAGE" to the device.

I was looking for a way to verify the address passed in was valid before
creating and inserting a new probe.

Maybe there is a better way to verify a kernel address is valid before
messing
with it?

-rusty
----- Original Message -----
From: "Rusty Lynch" <rusty@linux.co.intel.com>
To: "Arjan van de Ven" <arjanv@redhat.com>; "Andi Kleen" <ak@suse.de>
Cc: <linux-kernel@vger.kernel.org>; <rusty@linux.co.intel.com>
Sent: Wednesday, November 13, 2002 1:24 PM
Subject: Re: [PATCH][2.5.47]Add exported valid_kernel_address()

> I had a need for it in a sample kprobes driver where I wanted to verify
that
> some address
> was a valid kernel space address before I handed a probe to kprobes.
>
> So I would do something like:
>
> if (!valid_kernel_address(probe->addr)) {
> ret = -EINVAL;
> goto out;
> }
>
> register_kprobe(probe);
>
> and then kpboes will go and attempt to set *(probe->addr) = BREAK_POINT;
>
> -rustyl
> ----- Original Message -----
> From: "Andi Kleen" <ak@suse.de>
> To: "Arjan van de Ven" <arjanv@redhat.com>
> Cc: <linux-kernel@vger.kernel.org>; <rusty@linux.co.intel.com>
> Sent: Wednesday, November 13, 2002 1:14 PM
> Subject: Re: [PATCH][2.5.47]Add exported valid_kernel_address()
>
>
> > Arjan van de Ven <arjanv@redhat.com> writes:
> >
> > > it is customary that people who ask for an export explain why they
need
> > > it.... would you mind explaining that ?
> >
> > For modular lkcd I guess. Make a lot of sense to do it modular.
> >
> > -Andi
>
> -
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