Re: [PATCH] Subject: kprobes-x86: correct post-eip value inpost_hander()

From: Ananth N Mavinakayanahalli
Date: Fri Mar 21 2008 - 07:31:31 EST


On Fri, Mar 21, 2008 at 12:08:04PM +0100, Ingo Molnar wrote:
>
> * Yakov Lerner <iler.ml@xxxxxxxxx> wrote:
>
> > I was trying to get the address of instruction to be executed next
> > after the kprobed instruction. But regs->eip in post_handler()
> > contains value which is useless to the user. It's pre-corrected value.
> > This value is difficult to use without access to resume_execution(),
> > which is not exported anyway. I moved the invocation of post_handler()
> > to *after* resume_execution(). Now regs->eip contains meaningful value
> > in post_handler().
> >
> > I do not think this change breaks any backward-compatibility. To make
> > meaning of the old value, post_handler() would need access to
> > resume_execution() which is not exported. I have difficulty to
> > believe that previous, uncorrected, regs->eip can be meaningfully used
> > in post_handler().
>
> thanks, i've added your patch to the .26 bucket of x86.git, but it would
> be nice to get an Ack/Nack from a kprobes person as well.

Ingo,

I've tested Yakov's more comprehensive patch on powerpc too. This has my
ack.

Acked-by: Ananth N Mavinakayanahalli <ananth@xxxxxxxxxx>
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