* [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc
@ 2026-09-09 9:29 Sven Schnelle
2026-09-09 17:41 ` Steven Rostedt
2026-09-09 23:41 ` Masami Hiramatsu
0 siblings, 2 replies; 4+ messages in thread
From: Sven Schnelle @ 2026-09-09 9:29 UTC (permalink / raw)
To: Steven Rostedt, Masami Hiramatsu, Mathieu Desnoyers, Shuah Khan
Cc: linux-kernel, linux-trace-kernel, linux-kselftest
The current regex also matches symbols in modules, which makes the
test fail on s390 where name_show is present only once in the kernel,
but also multiple times in modules:
000001b1401cdc20 t name_show
000001b0c05e6c40 t name_show [mdev]
000001b0c0495f30 t name_show [i2c_core]
Fix this by changing the regular expression to only match the function
name.
Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
---
.../selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
index bc9514428dba..07b1177c1634 100644
--- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
+++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
@@ -6,7 +6,7 @@
SYMBOL='name_show'
# We skip this test on kernel where SYMBOL is unique or does not exist.
-if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then
+if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}$" /proc/kallsyms)" -le '1' ]; then
exit_unsupported
fi
--
2.53.0
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc
2026-09-09 9:29 [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc Sven Schnelle
@ 2026-09-09 17:41 ` Steven Rostedt
2026-09-10 0:01 ` Masami Hiramatsu
2026-09-09 23:41 ` Masami Hiramatsu
1 sibling, 1 reply; 4+ messages in thread
From: Steven Rostedt @ 2026-09-09 17:41 UTC (permalink / raw)
To: Sven Schnelle
Cc: Masami Hiramatsu, Mathieu Desnoyers, Shuah Khan, linux-kernel,
linux-trace-kernel, linux-kselftest
On Wed, 9 Sep 2026 11:29:53 +0200
Sven Schnelle <svens@linux.ibm.com> wrote:
> The current regex also matches symbols in modules, which makes the
> test fail on s390 where name_show is present only once in the kernel,
> but also multiple times in modules:
>
> 000001b1401cdc20 t name_show
> 000001b0c05e6c40 t name_show [mdev]
> 000001b0c0495f30 t name_show [i2c_core]
>
> Fix this by changing the regular expression to only match the function
> name.
>
> Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
> ---
> .../selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> index bc9514428dba..07b1177c1634 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> @@ -6,7 +6,7 @@
> SYMBOL='name_show'
>
> # We skip this test on kernel where SYMBOL is unique or does not exist.
> -if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then
> +if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}$" /proc/kallsyms)" -le '1' ]; then
> exit_unsupported
> fi
>
Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
But I wonder if "type_show" or "init_once" is a better option than
"name_show"?
-- Steve
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc
2026-09-09 17:41 ` Steven Rostedt
@ 2026-09-10 0:01 ` Masami Hiramatsu
0 siblings, 0 replies; 4+ messages in thread
From: Masami Hiramatsu @ 2026-09-10 0:01 UTC (permalink / raw)
To: Steven Rostedt
Cc: Sven Schnelle, Masami Hiramatsu, Mathieu Desnoyers, Shuah Khan,
linux-kernel, linux-trace-kernel, linux-kselftest
On Wed, 9 Sep 2026 13:41:56 -0400
Steven Rostedt <rostedt@goodmis.org> wrote:
> On Wed, 9 Sep 2026 11:29:53 +0200
> Sven Schnelle <svens@linux.ibm.com> wrote:
>
> > The current regex also matches symbols in modules, which makes the
> > test fail on s390 where name_show is present only once in the kernel,
> > but also multiple times in modules:
> >
> > 000001b1401cdc20 t name_show
> > 000001b0c05e6c40 t name_show [mdev]
> > 000001b0c0495f30 t name_show [i2c_core]
> >
> > Fix this by changing the regular expression to only match the function
> > name.
> >
> > Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
> > ---
> > .../selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> > index bc9514428dba..07b1177c1634 100644
> > --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> > +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> > @@ -6,7 +6,7 @@
> > SYMBOL='name_show'
> >
> > # We skip this test on kernel where SYMBOL is unique or does not exist.
> > -if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then
> > +if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}$" /proc/kallsyms)" -le '1' ]; then
> > exit_unsupported
> > fi
> >
>
> Reviewed-by: Steven Rostedt <rostedt@goodmis.org>
>
> But I wonder if "type_show" or "init_once" is a better option than
> "name_show"?
Yeah, we have many other candidates :)
$ grep -E '[[:alnum:]]+ t [[:alpha:]][[:alnum:]_]+$' /proc/kallsyms | cut -d " " -f 3 | sort | uniq -cd | sort -nr | head
27 p4d_offset
20 type_show
20 dev_attr_name
17 dev_attr_modalias
16 pfn_to_mfn
15 name_show
14 modalias_show
14 dev_attr_type
13 init_once
13 format_attr_event
Maybe we can just fallback to this logic for finding available symbols?
Thanks,
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc
2026-09-09 9:29 [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc Sven Schnelle
2026-09-09 17:41 ` Steven Rostedt
@ 2026-09-09 23:41 ` Masami Hiramatsu
1 sibling, 0 replies; 4+ messages in thread
From: Masami Hiramatsu @ 2026-09-09 23:41 UTC (permalink / raw)
To: Sven Schnelle
Cc: Steven Rostedt, Mathieu Desnoyers, Shuah Khan, linux-kernel,
linux-trace-kernel, linux-kselftest
On Wed, 9 Sep 2026 11:29:53 +0200
Sven Schnelle <svens@linux.ibm.com> wrote:
> The current regex also matches symbols in modules, which makes the
> test fail on s390 where name_show is present only once in the kernel,
> but also multiple times in modules:
>
> 000001b1401cdc20 t name_show
> 000001b0c05e6c40 t name_show [mdev]
> 000001b0c0495f30 t name_show [i2c_core]
>
> Fix this by changing the regular expression to only match the function
> name.
Ah, nice catch! I'll add this fixes tag.
Fixes: 03b80ff8023a ("selftests/ftrace: Add new test case which checks non unique symbol")
Thanks,
>
> Signed-off-by: Sven Schnelle <svens@linux.ibm.com>
> ---
> .../selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> index bc9514428dba..07b1177c1634 100644
> --- a/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> +++ b/tools/testing/selftests/ftrace/test.d/kprobe/kprobe_non_uniq_symbol.tc
> @@ -6,7 +6,7 @@
> SYMBOL='name_show'
>
> # We skip this test on kernel where SYMBOL is unique or does not exist.
> -if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}" /proc/kallsyms)" -le '1' ]; then
> +if [ "$(grep -c -E "[[:alnum:]]+ t ${SYMBOL}$" /proc/kallsyms)" -le '1' ]; then
> exit_unsupported
> fi
>
> --
> 2.53.0
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2026-09-10 0:01 UTC | newest]
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2026-09-09 9:29 [PATCH] selftests/ftrace: Fix unique symbol check in kprobe_non_uniq_symbol.tc Sven Schnelle
2026-09-09 17:41 ` Steven Rostedt
2026-09-10 0:01 ` Masami Hiramatsu
2026-09-09 23:41 ` Masami Hiramatsu
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