Re: [PATCH bpf-next v9 4/5] bpf, x86: Emit ENDBR for indirect jump targets

[Xu Kuohai]

On 3/13/2026 6:15 PM, Leon Hwang wrote:
> > +#ifdef CONFIG_X86_KERNEL_IBT
> > +		if (bpf_insn_is_indirect_target(env, bpf_prog, i - 1))
> > +			EMIT_ENDBR();
> > +#endif
> NIT: is this CONFIG check necessary?
>
> EMIT_ENDBR already checks it.
>
> #ifdef CONFIG_X86_KERNEL_IBT
> #define EMIT_ENDBR()		EMIT(gen_endbr(), 4)
> #define EMIT_ENDBR_POISON()	EMIT(gen_endbr_poison(), 4)
> #else
> #define EMIT_ENDBR()
> #define EMIT_ENDBR_POISON()
> #endif

Well, the code was originally written exactly without the #ifdef, but it triggered
-Wempty-body warning: https://lore.kernel.org/bpf/202603051414.AAMjmOHv-lkp@xxxxxxxxx/.