diff mbox series

[v2] selftests/ftrace: Add test to exercize function tracer across cpu hotplug

Message ID 20231213113802.1278600-1-naveen@kernel.org
State Accepted
Commit 3425a2005b291b62b6f6deeeab1156839c41cf85
Headers show
Series [v2] selftests/ftrace: Add test to exercize function tracer across cpu hotplug | expand

Commit Message

Naveen N Rao Dec. 13, 2023, 11:38 a.m. UTC
Add a test to exercize cpu hotplug with the function tracer active to
ensure that sensitive functions in idle path are excluded from being
traced. This helps catch issues such as the one fixed by commit
4b3338aaa74d ("powerpc/ftrace: Fix stack teardown in ftrace_no_trace").

Signed-off-by: Naveen N Rao <naveen@kernel.org>
---
v2: Add a check for next available online cpu, as suggested by Masami.

 .../ftrace/test.d/ftrace/func_hotplug.tc      | 42 +++++++++++++++++++
 1 file changed, 42 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc


base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86

Comments

Naveen N Rao Jan. 12, 2024, 7:35 a.m. UTC | #1
Hi Shuah,

On Wed, Dec 13, 2023 at 10:06:29AM -0500, Steven Rostedt wrote:
> On Wed, 13 Dec 2023 21:54:50 +0900
> Masami Hiramatsu (Google) <mhiramat@kernel.org> wrote:
> 
> > On Wed, 13 Dec 2023 17:08:02 +0530
> > Naveen N Rao <naveen@kernel.org> wrote:
> > 
> > > Add a test to exercize cpu hotplug with the function tracer active to
> > > ensure that sensitive functions in idle path are excluded from being
> > > traced. This helps catch issues such as the one fixed by commit
> > > 4b3338aaa74d ("powerpc/ftrace: Fix stack teardown in ftrace_no_trace").
> > >   
> > 
> > Looks good to me.
> > 
> > Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > 
> > Thank you,
> > 
> 
> Thanks Naveen and Masami!
> 
> Shuah, can you take this through your tree?

Can you please pick up this patch?

- Naveen
diff mbox series

Patch

diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
new file mode 100644
index 000000000000..ccfbfde3d942
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
@@ -0,0 +1,42 @@ 
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0-or-later
+# description: ftrace - function trace across cpu hotplug
+# requires: function:tracer
+
+if ! which nproc ; then
+  nproc() {
+    ls -d /sys/devices/system/cpu/cpu[0-9]* | wc -l
+  }
+fi
+
+NP=`nproc`
+
+if [ $NP -eq 1 ] ;then
+  echo "We cannot test cpu hotplug in UP environment"
+  exit_unresolved
+fi
+
+# Find online cpu
+for i in /sys/devices/system/cpu/cpu[1-9]*; do
+	if [ -f $i/online ] && [ "$(cat $i/online)" = "1" ]; then
+		cpu=$i
+		break
+	fi
+done
+
+if [ -z "$cpu" ]; then
+	echo "We cannot test cpu hotplug with a single cpu online"
+	exit_unresolved
+fi
+
+echo 0 > tracing_on
+echo > trace
+
+: "Set $(basename $cpu) offline/online with function tracer enabled"
+echo function > current_tracer
+echo 1 > tracing_on
+(echo 0 > $cpu/online)
+(echo "forked"; sleep 1)
+(echo 1 > $cpu/online)
+echo 0 > tracing_on
+echo nop > current_tracer