Subject: Re: linux-next: build warnings after merge of the tip tree

From: Peter Zijlstra <[email-masked]>
Date: Mon, 21 Mar 2022 17:50:50 +0100

On Mon, Mar 21, 2022 at 12:45:51PM -0400, Steven Rostedt wrote:
> On Mon, 21 Mar 2022 17:40:32 +0100
> Peter Zijlstra <[email-masked]> wrote:
> 
> > func_B:
> > 	call __fentry__	/* push func_B */
> > 	...
> > 	call __fexit__	/* pop 1 + tails */
> > 	ret
> > 
> > func_A:
> > 	call __fentry__ /* push func_A */
> > 	...
> > 	call __ftail__  /* mark func_A tail */
> > 	jmp func_B
> > 
> > func_C:
> > 	call __fentry__ /* push func_C */
> > 	call func_A;
> > 	...
> > 	call __fexit__  /* pop 1 + tails */
> > 	ret;
> 
> This also assumes that we need to trace everything that is marked. I
> mentioned in another email, what do we do if we only trace funcA?

Like I said later on; if we inhibit tail-calls to notrace, this goes
away.