Messages in this thread | | | Date | Wed, 18 Nov 2020 13:58:23 -0500 | From | Steven Rostedt <> | Subject | Re: violating function pointer signature |
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On Wed, 18 Nov 2020 19:31:50 +0100 Florian Weimer <fw@deneb.enyo.de> wrote:
> * Segher Boessenkool: > > > On Wed, Nov 18, 2020 at 12:17:30PM -0500, Steven Rostedt wrote: > >> I could change the stub from (void) to () if that would be better. > > > > Don't? In a function definition they mean exactly the same thing (and > > the kernel uses (void) everywhere else, which many people find clearer). > > And I think () functions expected a caller-provided parameter save > area on powerpc64le, while (void) functions do not. It does not > matter for an empty function, but GCC prefers to use the parameter > save area instead of setting up a stack frame if it is present. So > you get stack corruption if you call a () function as a (void) > function. (The other way round is fine.)
I wonder if we should define on all architectures a void void_stub(void), in assembly, that just does a return, an not worry about gcc messing up the creation of the stub function.
On x86_64:
GLOBAL(void_stub) retq
And so on.
-- Steve
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