linux-kernel - [PATCH] selftests/ftrace: Add test to exercize function tracer across cpu hotplug

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Tue, 12 Dec 2023 14:26:07 +0530
From:   Naveen N Rao <naveen@...nel.org>
To:     <linux-kselftest@...r.kernel.org>, <linux-kernel@...r.kernel.org>
Cc:     Steven Rostedt <rostedt@...dmis.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Shuah Khan <shuah@...nel.org>,
        Michael Ellerman <mpe@...erman.id.au>
Subject: [PATCH] selftests/ftrace: Add test to exercize function tracer across cpu hotplug

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@...nel.org>
---
 .../ftrace/test.d/ftrace/func_hotplug.tc      | 30 +++++++++++++++++++
 1 file changed, 30 insertions(+)
 create mode 100644 tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc

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..49731a2b5c23
--- /dev/null
+++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_hotplug.tc
@@ -0,0 +1,30 @@
+#!/bin/sh
+# SPDX-License-Identifier: GPL-2.0
+# 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 can not test cpu hotplug in UP environment"
+  exit_unresolved
+fi
+
+echo 0 > tracing_on
+echo > trace
+: "Set CPU1 offline/online with function tracer enabled"
+echo function > current_tracer
+echo 1 > tracing_on
+(echo 0 > /sys/devices/system/cpu/cpu1/online)
+(echo "forked"; sleep 1)
+(echo 1 > /sys/devices/system/cpu/cpu1/online)
+echo 0 > tracing_on
+
+: "Check CPU1 events are recorded"
+grep -q -e "\[001\]" trace

base-commit: b85ea95d086471afb4ad062012a4d73cd328fa86
-- 
2.43.0