[PATCH 2/3] selftests/livepatch: use $(dmesg --notime) instead of manually filtering

[Joe Lawrence <joe.lawrence@redhat.com>]

The dmesg utility already comes with a command line switch to omit
kernel timestamps, let's use it instead of applying an extra regex to
filter them out.

Now without the '[timestamp]: ' prefix at the beginning of the log
entry, revise the filtering regex to search for the 'livepatch:'
subsystem prefix at the beginning of the line.

Signed-off-by: Joe Lawrence <joe.lawrence@redhat.com>
---
 tools/testing/selftests/livepatch/README       | 8 ++++----
 tools/testing/selftests/livepatch/functions.sh | 7 +++----
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/livepatch/README b/tools/testing/selftests/livepatch/README
index 0942dd5826f8..79dafab03017 100644
--- a/tools/testing/selftests/livepatch/README
+++ b/tools/testing/selftests/livepatch/README
@@ -37,7 +37,7 @@ Adding tests
 See the common functions.sh file for the existing collection of utility
 functions, most importantly setup_config(), start_test() and
 check_result().  The latter function greps the kernel's ring buffer for
-"livepatch:" and "test_klp" strings, so tests be sure to include one of
-those strings for result comparison.  Other utility functions include
-general module loading and livepatch loading helpers (waiting for patch
-transitions, sysfs entries, etc.)
+the "^livepatch:" subsystem prefix and also any "test_klp" strings.
+Test log entries need include one of those for result comparison.  Other
+utility functions include general module loading and livepatch loading
+helpers (waiting for patch transitions, sysfs entries, etc.)
diff --git a/tools/testing/selftests/livepatch/functions.sh b/tools/testing/selftests/livepatch/functions.sh
index e84375a33852..83560c3df2ee 100644
--- a/tools/testing/selftests/livepatch/functions.sh
+++ b/tools/testing/selftests/livepatch/functions.sh
@@ -248,7 +248,7 @@ function start_test {
 
 	# Save existing dmesg so we can detect new content below
 	SAVED_DMESG=$(mktemp --tmpdir -t klp-dmesg-XXXXXX)
-	dmesg > "$SAVED_DMESG"
+	dmesg --notime > "$SAVED_DMESG"
 
 	echo -n "TEST: $test ... "
 }
@@ -259,9 +259,8 @@ function check_result {
 	local expect="$*"
 	local result
 
-	result=$(dmesg | diff --changed-group-format='%>' --unchanged-group-format='' "$SAVED_DMESG" - | \
-		 grep -v 'tainting' | grep -e 'livepatch:' -e 'test_klp' | \
-		 sed 's/^\[[ 0-9.]*\] //')
+	result=$(dmesg --notime | diff --changed-group-format='%>' --unchanged-group-format='' "$SAVED_DMESG" - | \
+		 grep -v 'tainting' | grep -e '^livepatch:' -e 'test_klp')
 
 	if [[ "$expect" == "$result" ]] ; then
 		echo "ok"
-- 
2.21.3