Re: [PATCH 1/2] selftests/ftrace: Force C locale for readelf in uprobe test

[Masami Hiramatsu (Google) <mhiramat@kernel.org>]

On Thu,  6 Aug 2026 16:31:00 +0800
"Rui Qi" <qirui.001@bytedance.com> wrote:

> The add_remove_uprobe test parses the entry point from readelf -h output
> by looking for the English "Entry" field. readelf output is localized
> via gettext, while the ftracetest runner does not force LC_ALL=C and the
> top-level Makefile leaves LANG effective for child processes.

Hmm, to make it safer, I think we should force LC_ALL=C in the top level
of ftracetest, instead of setting it in each test case.

Thank you,

> 
> If readelf prints a translated field name, ENTRYPOINT becomes empty and
> the uprobe_events write is rejected because the offset after PATH: is
> missing.
> 
> Run readelf with LC_ALL=C so the parsed header field remains stable
> across locales.
> 
> Signed-off-by: Rui Qi <qirui.001@bytedance.com>
> ---
>  .../selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc       | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc
> index f2048c244526..f33a863be68b 100644
> --- a/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc
> +++ b/tools/testing/selftests/ftrace/test.d/dynevent/add_remove_uprobe.tc
> @@ -12,7 +12,7 @@ echo 0 > events/enable
>  echo > dynamic_events
>  
>  REALBIN=`readlink -f /bin/sh`
> -ENTRYPOINT=`readelf -h ${REALBIN} | grep Entry | sed -e 's/[^0]*//'`
> +ENTRYPOINT=`LC_ALL=C readelf -h ${REALBIN} | grep Entry | sed -e 's/[^0]*//'`
>  
>  echo "p:myevent ${REALBIN}:${ENTRYPOINT}" >> uprobe_events
>  
> -- 
> 2.20.1


-- 
Masami Hiramatsu (Google) <mhiramat@kernel.org>