On Tue, 15 Oct 2019, Joe Lawrence wrote:

On 10/15/19 7:23 AM, Miroslav Benes wrote:

quoted

quoted

Hi Miroslav,

Maybe we should add a test to verify this new behavior?  See sample
version below (lightly tested).  We can add to this one, or patch
seperately if you prefer.

Thanks a lot, Joe. It looks nice. I'll include it in v3. One question
below.
  

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-->8-- -->8-- -->8-- -->8-- -->8-- -->8-- -->8-- -->8-- -->8-- -->8--

  

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From c8c9f22e3816ca4c90ab7e7159d2ce536eaa5fad Mon Sep 17 00:00:00 2001

From: Joe Lawrence <joe.lawrence@redhat.com>
Date: Mon, 14 Oct 2019 18:25:01 -0400
Subject: [PATCH] selftests/livepatch: test interaction with ftrace_enabled

Since livepatching depends upon ftrace handlers to implement "patched"
functionality, verify that the ftrace_enabled sysctl value interacts
with livepatch registration as expected.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
---
  tools/testing/selftests/livepatch/Makefile    |  3 +-
  .../testing/selftests/livepatch/functions.sh  | 18 +++++
  .../selftests/livepatch/test-ftrace.sh        | 65 +++++++++++++++++++
  3 files changed, 85 insertions(+), 1 deletion(-)
  create mode 100755 tools/testing/selftests/livepatch/test-ftrace.sh

diff --git a/tools/testing/selftests/livepatch/Makefile

b/tools/testing/selftests/livepatch/Makefile
index fd405402c3ff..1886d9d94b88 100644

--- a/tools/testing/selftests/livepatch/Makefile
+++ b/tools/testing/selftests/livepatch/Makefile

@@ -4,6 +4,7 @@ TEST_PROGS_EXTENDED := functions.sh
  TEST_PROGS := \
   test-livepatch.sh \
   test-callbacks.sh \
-	test-shadow-vars.sh
+	test-shadow-vars.sh \
+	test-ftrace.sh
  
  include ../lib.mk

diff --git a/tools/testing/selftests/livepatch/functions.sh

b/tools/testing/selftests/livepatch/functions.sh
index 79b0affd21fb..556252efece0 100644

--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh

@@ -52,6 +52,24 @@ function set_dynamic_debug() {
  		EOF
  }
  
+function push_ftrace_enabled() {
+	FTRACE_ENABLED=$(sysctl --values kernel.ftrace_enabled)
+}

Shouldn't we call push_ftrace_enabled() somewhere at the beginning of the
test script? set_dynamic_debug() calls its push_dynamic_debug() directly,
but set_ftrace_enabled() is different, because it is called more than once
in the script.

One could argue that ftrace_enabled has to be true at the beginning of
testing anyway, but I think it would be cleaner. Btw, we should probably
guarantee that ftrace_enabled is true when livepatch selftests are
invoked.

Ah yes, that occurred to me while creating that piece of the patch. Something
like setup_test_config() that pushes both ftrace and the debugfs, etc. would
be cleaner for all scripts.  If you're onboard with that idea, I can make that
revision.

Yes, that would be perfect. Thanks.

Miroslav