On Wed, 2024-08-28 at 22:45 -0700, Eduard Zingerman wrote:

[...]

> I will prepare a test case.
> Probably tomorrow.

Please find test in the attachment. This test triggers KASAN error
report as in another attachment. (I enabled CONFIG_KASAN using
menuconfig on top of regular selftest config).

On Fri, Aug 23, 2024 at 3:43 AM Jeongjun Park <aha310510@gmail.com> wrote:

[...]

> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 520f49f422fe..5c24ea1a65a4 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c
> @@ -823,6 +823,9 @@ static bool btf_name_valid_section(const struct btf *btf, u32 offset)
>         const char *src = btf_str_by_offset(btf, offset);
>         const char *src_limit;
> 
> +       if (!*src)
> +               return false;
> +

I think that correct fix would be as follows:

---

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index edad152cee8e..d583d76fcace 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -820,7 +820,6 @@ static bool btf_name_valid_section(const struct btf *btf, u32 offset)
 
        /* set a limit on identifier length */
        src_limit = src + KSYM_NAME_LEN;
-       src++;
        while (*src && src < src_limit) {
                if (!isprint(*src))
                        return false;