Re: [PATCH] tracing/selftests: Ignore __pfx_ symbols in kprobe test

[Google]

On Tue, 7 Feb 2023 13:51:47 -0500
Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:

> From: "Steven Rostedt (Google)" <rostedt@xxxxxxxxxxx>
> 
> The kprobe probepoint.tc test started failing because of the added __pfx_
> symbols that were added because of -fpatchable-function-entry=X,Y causing
> unwinders to see them as part of the previous functions. But kprobes can
> not be added on top of them. The selftest looks for tracefs_create_dir and
> picks it and the previous and following functions to add at their address.
> This caused it to include __pfx_tracefs_create_dir which is invalid to
> attach a kprobe to and caused the test to fail.
> 
> Fixes: 9f2899fe36a62 ("objtool: Add option to generate prefix symbols")
> Signed-off-by: Steven Rostedt (Google) <rostedt@xxxxxxxxxxx>

This looks good to me. 

Acked-by: 

Thanks,

> ---
>  tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
> index 624269c8d534..e1b7506c1b11 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/probepoint.tc
> @@ -21,7 +21,7 @@ set_offs() { # prev target next
>  
>  # We have to decode symbol addresses to get correct offsets.
>  # If the offset is not an instruction boundary, it cause -EILSEQ.
> -set_offs `grep -A1 -B1 ${TARGET_FUNC} /proc/kallsyms | cut -f 1 -d " " | xargs`
> +set_offs `grep -v __pfx_ /proc/kallsyms | grep -A1 -B1 ${TARGET_FUNC} |  cut -f 1 -d " " | xargs`
>  
>  UINT_TEST=no
>  # printf "%x" -1 returns (unsigned long)-1.
> -- 
> 2.39.0
> 


-- 
Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>