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

[Peter Zijlstra]

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.