Re: [PATCH 1/1] ptrace: Get tracer PID without reliance on the proc FS

[Oleg Nesterov]

We certainly can't understand each other. At least, I certainly can't.

On 09/10, Roman Kisel wrote:
>
> On 09/09, Oleg wrote:
>

> > Yet another thing in this discussion I can't understand... sorry, I tried.
> > You do not need to teach, say, gdb to recognize this pattern. You can just do
> >
> > 	$ gdb -ex 'b please_insert_the_breakpoint_here' ...
> >
> > Nevermind, as I have already said you can safely ignore me. I still do not
> > see any "real" use-case for breakpoint_if_debugging(), but I guess that is
> > due to my ignorance and lack of imagination.
>
> I've started this so let me butt in and take up the gaunlet.
>
> Lambda's would be the most prominent example to me[1]. The toolchain
> doesn't give them the user-accesible type and the name as it does for
> the functions.

And?

Once again, what I tried to suggest is a single "nop" function,
"void please_insert_the_breakpoint_here()" which simply does asm("ret") and

	#define breakpoint_if_debugging()	\
		please_insert_the_breakpoint_here()

Or, to make it more cheap,

	#define breakpoint_if_debugging()	\
		asm volatile ("call please_insert_the_breakpoint_here" : ASM_CALL_CONSTRAINT);

so that compiler will know that breakpoint_if_debugging() doesn't change the regs.

Again, again, I am not saying that this is necessarily the best solution.
Just I fail to understand your email, sorry.

Oleg.