Re: [PATCH v3 18/39] x86/ibt,ftrace: Make function-graph play nice

[Peter Zijlstra]

On Fri, Mar 04, 2022 at 09:51:54AM -0800, Josh Poimboeuf wrote:
> On Thu, Mar 03, 2022 at 12:23:39PM +0100, Peter Zijlstra wrote:
> > +
> > +	addq $16, %rsp
> > +	ANNOTATE_INTRA_FUNCTION_CALL
> > +	call .Ldo_rop
> > +	int3
> > +.Ldo_rop:
> > +	mov %rdi, (%rsp)
> > +	UNWIND_HINT_FUNC
> > +	RET
> 
> Why the int3?

Speculation trap :-) Either I'm too paranoid or not paranoid enough; but
without it it's just too close to a retpoline and it doesn't feel right.