Re: [RFC][PATCH 1/2] x86: Allow breakpoints to emulate call functions

[Steven Rostedt]

On Thu, 2 May 2019 11:02:40 -0700
Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> Indeed, the 32-bit case for same-RPL exceptions/iret is entirely
> different, and I'd forgotten about that.
> 
> And honestly, this makes the 32-bit case much worse. Now the entry
> stack modifications of int3 suddenly affect not just the entry, but
> every exit too.
> 
> This is _exactly_ the kind of subtle kernel entry/exit code I wanted
> us to avoid.

I just want to point out that I never got the trampoline version
working on i386. I didn't have the time to debug why it would crash
when stressed.

-- Steve