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References: <20240311204019.1183634-1-bjohannesmeyer@gmail.com> <20240311204019.1183634-8-bjohannesmeyer@gmail.com>
In-Reply-To: <20240311204019.1183634-8-bjohannesmeyer@gmail.com>
From: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
Date: Thu, 11 Apr 2024 12:28:29 -0700
Message-ID: <CAOZ5it1NaWyUM4GTJ+XrMet7aQXT27q1VZ4FeD8osbTccVpj9w@mail.gmail.com>
Subject: Re: [PATCH 7/7] scripts/faddr2line: Check only two symbols when
 calculating symbol size
To: Josh Poimboeuf <jpoimboe@kernel.org>, linux-kernel@vger.kernel.org, 
	Brian Johannesmeyer <bjohannesmeyer@gmail.com>
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On Mon, Mar 11, 2024 at 1:40=E2=80=AFPM Brian Johannesmeyer
<bjohannesmeyer@gmail.com> wrote:
>
> Rather than looping through each symbol in a particular section to
> calculate a symbol's size, grep for the symbol and its immediate
> successor, and only use those two symbols.
>
> Signed-off-by: Brian Johannesmeyer <bjohannesmeyer@gmail.com>
> ---
>  scripts/faddr2line | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/faddr2line b/scripts/faddr2line
> index 1fa6beef9f97..70d5a4602a92 100755
> --- a/scripts/faddr2line
> +++ b/scripts/faddr2line
> @@ -252,7 +252,7 @@ __faddr2line() {
>                                 found=3D2
>                                 break
>                         fi
> -               done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -=
v sec=3D$sym_sec '$7 =3D=3D sec' | sort --key=3D2)
> +               done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -=
v sec=3D$sym_sec '$7 =3D=3D sec' | sort --key=3D2 | ${GREP} -A1 " ${sym_nam=
e}$")
>
>                 if [[ $found =3D 0 ]]; then
>                         warn "can't find symbol: sym_name: $sym_name sym_=
sec: $sym_sec sym_addr: $sym_addr sym_elf_size: $sym_elf_size"
> --
> 2.34.1
>

Hey Josh,

I just noticed that this patch does not correctly handle duplicate
sym_names. To fix, the "--no-group-separator" option should be added
as follows:

> -               done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -=
v sec=3D$sym_sec '$7 =3D=3D sec' | sort --key=3D2)
> +               done < <(echo "${ELF_SYMS}" | sed 's/\[.*\]//' | ${AWK} -=
v sec=3D$sym_sec '$7 =3D=3D sec' | sort --key=3D2 | ${GREP} -A1 --no-group-=
separator " ${sym_name}$")

Would you like me to re-submit the patch series with this fix?

Thanks,

Brian