Re: [RFC][PATCH 04/17] objtool/x86: Fix SRSO mess

[Peter Zijlstra]

On Thu, Aug 10, 2023 at 05:02:01PM +0200, Borislav Petkov wrote:
> On Thu, Aug 10, 2023 at 02:50:05PM +0200, Peter Zijlstra wrote:
> > Notably 'call RET' is not what this is about. I hope the below
> > clarifies.
> 
> Yah, it does, now that you've taken the time to explain it. Looking at
> the commit which added it:
> 
>   15e67227c49a ("x86: Undo return-thunk damage")
> 
> it doesn't even begin to explain it. Can you please put the gist of what
> you've explained here in a comment over patch_return() as it is not
> really obvious - at least to me it isn't - what the rules for the thunks
> are.
> 
> I mean, they're clear now but I think we should hold them down
> explicitly. Especially with all the crazy patching we're doing now.

Will update.