On Mon, 7 Jun 2021 13:44:21 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:
> There's an extended section header index section for just that. And
> recordmcount actually seems to use that as well.
>
> I can't seem to find enough of the thread to figure out what the actual
> problem is though. The lore archive doesn't have anything prior to this
> message.
>
> One should only use st_shndx when >SHN_UDEF and <SHN_LORESERVE. When
> SHN_XINDEX, then use .symtab_shndx.
>
> Apparently you've found a case where neither is true? In that case
> objtool seems to use shndx 0. A matching recordmcount patch would be
> something like this.
Mark-PK,
Does the below patch fix it for you too (if you backport it to your
kernel). I much rather have recordmcount match objtool, as one day the
two will hopefully merge to one executable.
-- Steve
>
>
> diff --git a/scripts/recordmcount.h b/scripts/recordmcount.h
> index f9b19524da11..d99cc0aed6fe 100644
> --- a/scripts/recordmcount.h
> +++ b/scripts/recordmcount.h
> @@ -194,13 +194,18 @@ static unsigned int get_symindex(Elf_Sym const *sym, Elf32_Word const *symtab,
> unsigned long offset;
> int index;
>
> - if (sym->st_shndx != SHN_XINDEX)
> + if (sym->st_shndx > SHN_UDEF &&
> + sym->st_shndx < SHN_LORESERVE)
> return w2(sym->st_shndx);
>
> - offset = (unsigned long)sym - (unsigned long)symtab;
> - index = offset / sizeof(*sym);
> + if (sym->st_shndx == SHN_XINDEX) {
> + offset = (unsigned long)sym - (unsigned long)symtab;
> + index = offset / sizeof(*sym);
>
> - return w(symtab_shndx[index]);
> + return w(symtab_shndx[index]);
> + }
> +
> + return 0;
> }
>
> static unsigned int get_shnum(Elf_Ehdr const *ehdr, Elf_Shdr const *shdr0)
