On Tue, Jul 15, 2025 at 5:27 PM Ihor Solodrai <ihor.solodrai@xxxxxxxxx> wrote:
>
> On 7/14/25 4:49 PM, Ihor Solodrai wrote:
> > On 7/8/25 1:07 PM, Alexei Starovoitov wrote:
> >> On Thu, Jul 3, 2025 at 5:18 AM Menglong Dong
> >> <menglong8.dong@xxxxxxxxx> wrote:
> >>>
> >>> + return true;
> >>> +
> >>> + /* Following symbols have multi definition in kallsyms, take
> >>> + * "t_next" for example:
> >>> + *
> >>> + * ffffffff813c10d0 t t_next
> >>> + * ffffffff813d31b0 t t_next
> >>> + * ffffffff813e06b0 t t_next
> >>> + * ffffffff813eb360 t t_next
> >>> + * ffffffff81613360 t t_next
> >>> + *
> >>> + * but only one of them have corresponding mrecord:
> >>> + * ffffffff81613364 t_next
> >>> + *
> >>> + * The kernel search the target function address by the symbol
> >>> + * name "t_next" with kallsyms_lookup_name() during attaching
> >>> + * and the function "0xffffffff813c10d0" can be matched, which
> >>> + * doesn't have a corresponding mrecord. And this will make
> >>> + * the attach failing. Skip the functions like this.
> >>> + *
> >>> + * The list maybe not whole, so we still can fail......We need a
> >>> + * way to make the whole things right. Yes, we need fix it :/
> >>> + */
> >>> + if (!strcmp(name, "kill_pid_usb_asyncio"))
> >>> + return true;
> >>> + if (!strcmp(name, "t_next"))
> >>> + return true;
> >>> + if (!strcmp(name, "t_stop"))
> >>> + return true;
>
> This little patch will filter out from BTF any static functions with
> the same name that appear more than once.
>
> diff --git a/btf_encoder.c b/btf_encoder.c
> index 0bc2334..6441269 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -96,7 +96,8 @@ struct elf_function {
> const char *name;
> char *alias;
> size_t prefixlen;
> - bool kfunc;
> + uint8_t is_static:1;
> + uint8_t kfunc:1;
> uint32_t kfunc_flags;
> };
>
> @@ -1374,7 +1375,7 @@ static int saved_functions_combine(struct
> btf_encoder_func_state *a, struct btf_
> return ret;
> optimized = a->optimized_parms | b->optimized_parms;
> unexpected = a->unexpected_reg | b->unexpected_reg;
> - inconsistent = a->inconsistent_proto | b->inconsistent_proto;
> + inconsistent = a->inconsistent_proto | b->inconsistent_proto |
> a->elf->is_static | b->elf->is_static;
> if (!unexpected && !inconsistent && !funcs__match(a, b))
> inconsistent = 1;
> a->optimized_parms = b->optimized_parms = optimized;
> @@ -1461,6 +1462,8 @@ static void elf_functions__collect_function(struct
> elf_functions *functions, GEl
>
> func = &functions->entries[functions->cnt];
> func->name = name;
> + func->is_static = elf_sym__bind(sym) == STB_LOCAL;
> +
Hmm. We definitely don't want to filter out all static functions.
That's too drastic.
