Re: [PATCH bpf-next 0/4] Use correct destructor kfunc types

[Sami Tolvanen]

Hi,

On Fri, Jul 25, 2025 at 9:05 AM Yonghong Song <yonghong.song@xxxxxxxxx> wrote:
>
> I tried your patch set on top of latest bpf-next. The problem
> still exists with the following error:
>
> [   71.976265] CFI failure at bpf_obj_free_fields+0x298/0x620 (target: __bpf_crypto_ctx_release+0x0/0x10; expected type: 0xc1113566)
> [   71.980134] Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
> ...
>
>
> The following is the CFI related config items:
>
> $ grep CFI .config
> CONFIG_CFI_AUTO_DEFAULT=y
> CONFIG_FUNCTION_PADDING_CFI=11
> CONFIG_ARCH_SUPPORTS_CFI_CLANG=y
> CONFIG_ARCH_USES_CFI_TRAPS=y
> CONFIG_CFI_CLANG=y
> # CONFIG_CFI_ICALL_NORMALIZE_INTEGERS is not set
> CONFIG_HAVE_CFI_ICALL_NORMALIZE_INTEGERS_CLANG=y
> CONFIG_HAVE_CFI_ICALL_NORMALIZE_INTEGERS_RUSTC=y
> # CONFIG_CFI_PERMISSIVE is not set
>
> Did I miss anything?

Interesting. I tested this on arm64 and confirmed that the issue is
fixed there, so I wonder if we need to use KCFI_REFERENCE() here to
make sure objtool / x86 runtime patching knows this function actually
indirectly called. I'll test this on x86 and see what's going on.

Thanks for taking a look!

Sami