2023-09-14 13:16:20

by Will Deacon

Subject: [PATCH v4 1/3] scripts/faddr2line: Don't filter out non-function symbols from readelf

As Josh points out in 20230724234734.zy67gm674vl3p3wv@treble:

> Problem is, I think the kernel's symbol printing code prints the
> nearest kallsyms symbol, and there are some valid non-FUNC code
> symbols. For example, syscall_return_via_sysret.

so we shouldn't be considering only 'FUNC'-type symbols in the output
from readelf.

Drop the function symbol type filtering from the faddr2line outer loop.

Cc: Josh Poimboeuf <[email protected]>
Cc: John Stultz <[email protected]>
Link: https://lore.kernel.org/r/20230724234734.zy67gm674vl3p3wv@treble
Signed-off-by: Will Deacon <[email protected]>
---
scripts/faddr2line | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/faddr2line b/scripts/faddr2line
index 0e73aca4f908..a35a420d0f26 100755
--- a/scripts/faddr2line
+++ b/scripts/faddr2line
@@ -260,7 +260,7 @@ __faddr2line() {

DONE=1

- done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
+ done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')
}

[[ $# -lt 2 ]] && usage
--
2.42.0.283.g2d96d420d3-goog

2023-09-18 16:58:34

by Nick Desaulniers

Subject: Re: [PATCH v4 1/3] scripts/faddr2line: Don't filter out non-function symbols from readelf

On Thu, Sep 14, 2023 at 6:12 AM Will Deacon <[email protected]> wrote:
>
> As Josh points out in 20230724234734.zy67gm674vl3p3wv@treble:

Perhaps a suggested-by tag would be appropriate then? Next time.

>
> > Problem is, I think the kernel's symbol printing code prints the
> > nearest kallsyms symbol, and there are some valid non-FUNC code
> > symbols. For example, syscall_return_via_sysret.
>
> so we shouldn't be considering only 'FUNC'-type symbols in the output
> from readelf.
>
> Drop the function symbol type filtering from the faddr2line outer loop.
>
> Cc: Josh Poimboeuf <[email protected]>
> Cc: John Stultz <[email protected]>
> Link: https://lore.kernel.org/r/20230724234734.zy67gm674vl3p3wv@treble
> Signed-off-by: Will Deacon <[email protected]>

LGTM; thanks for the patch!
Reviewed-by: Nick Desaulniers <[email protected]>

> ---
> scripts/faddr2line | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/scripts/faddr2line b/scripts/faddr2line
> index 0e73aca4f908..a35a420d0f26 100755
> --- a/scripts/faddr2line
> +++ b/scripts/faddr2line
> @@ -260,7 +260,7 @@ __faddr2line() {
>
> DONE=1
>
> - done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$4 == "FUNC" && $8 == fn')
> + done < <(${READELF} --symbols --wide $objfile | sed 's/\[.*\]//' | ${AWK} -v fn=$sym_name '$8 == fn')
> }
>
> [[ $# -lt 2 ]] && usage
> --
> 2.42.0.283.g2d96d420d3-goog
>


--
Thanks,
~Nick Desaulniers