Re: [PATCH bpf-next v2 4/4] selftests/bpf: Test jited inline of bpf_get_smp_processor_id() for LoongArch

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Medium] Broken selftest due to missing kernel JIT implementation and incorrect structural offset
--

commit 8f74b6910905428534e06ac6efaea6a8091a844f
Author: Tiezhu Yang <yangtiezhu@loongson.cn>

selftests/bpf: Test jited inline of bpf_get_smp_processor_id() for LoongArch

This commit adds a BPF selftest for LoongArch to verify that the
bpf_get_smp_processor_id() helper is correctly inlined by the JIT compiler.

> diff --git a/tools/testing/selftests/bpf/progs/verifier_jit_inline.c b/tools/testing/selftests/bpf/progs/verifier_jit_inline.c
> index 8560577f25576..02e562f56f9d3 100644
> --- a/tools/testing/selftests/bpf/progs/verifier_jit_inline.c
> +++ b/tools/testing/selftests/bpf/progs/verifier_jit_inline.c
> @@ -21,4 +21,15 @@ int inline_bpf_get_current_task(void)
>  	return 0;
>  }
>  
> +SEC("fentry/bpf_fentry_test2")
> +__success __retval(0)
> +__arch_loongarch
> +__jited("	ld.wu	$a5, $tp, 16")

[Severity: Medium]
Will this test fail in the current tree? It appears the kernel-side JIT 
implementation to inline this helper on LoongArch is missing. Without it, 
this test will expect an inline load but the JIT will generate a standard 
function call, causing the assertion to fail.

Also, is the offset 16 correct here? In the current tree's LoongArch layout,
struct thread_info contains a task pointer at offset 0, which means the cpu
field is at offset 24, not 16. The test appears to rely on an out-of-tree
configuration or prerequisite patch where the offset is 16.

> +int inline_bpf_get_smp_processor_id(void)
> +{
> +	bpf_get_smp_processor_id();
> +
> +	return 0;
> +}
> +
>  char _license[] SEC("license") = "GPL";

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260615100506.19558-1-yangtiezhu@loongson.cn?part=4