Re: violating function pointer signature

Steven Rostedt
2020-11-18T14:03:26Z

On Wed, 18 Nov 2020 14:21:36 +0100
Peter Zijlstra <peterz@infradead.org> wrote:

> I think that as long as the function is completely empty (it never
> touches any of the arguments) this should work in practise.
>
> That is:
>
> void tp_nop_func(void) { }

My original version (the OP of this thread) had this:

+static void tp_stub_func(void)
+{
+ return;
+}

>
> can be used as an argument to any function pointer that has a void
> return. In fact, I already do that, grep for __static_call_nop().
>
> I'm not sure what the LLVM-CFI crud makes of it, but that's their
> problem.

If it is already done elsewhere in the kernel, then I will call this
precedence, and keep the original version.

This way Alexei can't complain about adding a check in the fast path of
more than one callback attached.

-- Steve