Re: [PATCH v2 1/2] x86/kprobes: Fix kprobes instruction boudary check with CONFIG_RETHUNK

Peter Zijlstra
2022-09-08T10:08:38Z

On Thu, Sep 08, 2022 at 11:30:41AM +0200, Peter Zijlstra wrote:
> Once that lands the rules are:
>
> 0-5 INT3 after RET, !CONFIG_RETHUNK && !CONFIG_SLS: 0
> CONFIG_SLS: 1
> CONFIG_RETHUNK: 4-5 depending on compiler version
>
> 0-1 INT3 after RET: !CONFIG_SLS: 0
> CONFIG_SLS: 0-1 depending on compiler version
>
> Now, given we know the compiler version at build time, this could be
> determined and used in kprobes, but meh.

Oh also, for giggles, we have a number of sites that have ret;int3
independent of CONFIG_SLS because that was easier than figuring out what
all should be done.