Re: violating function pointer signature

Steven Rostedt
2020-11-18T20:02:59Z

On Wed, 18 Nov 2020 11:46:02 -0800
Alexei Starovoitov <alexei.starovoitov@gmail.com> wrote:

> On Wed, Nov 18, 2020 at 6:22 AM Steven Rostedt <rostedt@goodmis.org> wrote:
> >
> > Thus, all functions will be non-variadic in these cases.
>
> That's not the only case where it will blow up.
> Try this on sparc:
> struct foo {
> int a;
> };
>
> struct foo foo_struct(void) {
> struct foo f = {};
> return f;
> }
> int foo_int(void) {
> return 0;
> }
> or this link:
> https://godbolt.org/z/EdM47b
>
> Notice:
> jmp %i7+12
> The function that returns small struct will jump to a different
> instruction in the caller.
>
> I think none of the tracepoints return structs and void foo(void) is
> fine on x86.
> Just pointing out that it's more than just variadic.

I also said that this is limited to only functions that have void return.

-- Steve