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From:   Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
To:     Steven Rostedt <rostedt@goodmis.org>,
        Ingo Molnar <mingo@redhat.com>, Shuah Khan <shuah@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
        linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-rt-users@vger.kernel.org, joseph.salisbury@canonical.com
Subject: [PATCH] selftests/ftrace: Do not trace do_softirq because of PREEMPT_RT
Date:   Wed,  9 Feb 2022 17:24:30 +0100
Message-Id: <20220209162430.286578-1-krzysztof.kozlowski@canonical.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

The PREEMPT_RT patchset does not use soft IRQs thus trying to filter for
do_softirq fails for such kernel:

  echo do_softirq
  ftracetest: 81: echo: echo: I/O error

Choose some other externally visible function for the test.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>

---

I understand that the failure does not exist on mainline kernel (only
with PREEMPT_RT patchset) but the change does not harm it.

If it is not suitable alone, please consider it for RT patchset.
---
 .../selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc      | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
index e96e279e0533..1d0c7601865f 100644
--- a/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
+++ b/tools/testing/selftests/ftrace/test.d/ftrace/func_set_ftrace_file.tc
@@ -19,7 +19,7 @@ fail() { # mesg
 
 FILTER=set_ftrace_filter
 FUNC1="schedule"
-FUNC2="do_softirq"
+FUNC2="_printk"
 
 ALL_FUNCS="#### all functions enabled ####"
 
-- 
2.32.0