Subject: [PATCH 2/2] tests/shell: Fix perf test shell to check for libtracevent support

From: Athira Rajeev <[email-masked]>
Date: Wed, 1 Feb 2023 23:34:21 +0530

Test “Use vfs_getname probe to get syscall args filenames”
fails in environment with missing libtraceevent
support as below:

 82: Use vfs_getname probe to get syscall args filenames             :
--- start ---
test child forked, pid 304726
Recording open file:
event syntax error: 'probe:vfs_getname*'
                     \___ unsupported tracepoint

libtraceevent is necessary for tracepoint support
Run 'perf list' for a list of valid events

 Usage: perf record [<options>] [<command>]
    or: perf record [<options>] -- <command> [<options>]

    -e, --event <event>   event selector. use 'perf list' to list available events
test child finished with -1
---- end ----
Use vfs_getname probe to get syscall args filenames: FAILED!

The environment has debuginfo but is missing the libtraceevent
devel. Hence perf is compiled without libtraceevent support.
The test tries to add probe “probe:vfs_getname” and then
uses it with “perf record”.  This fails at function
“parse_events_add_tracepoint" due to missing libtraceevent.

Similarly "probe libc's inet_pton & backtrace it with ping" test
slso fails with same reason.

Add a function in 'perf test shell' library to check if perf
record with —dry-run reports any error on missing support
for libtraceevent. Update both the tests to use this new
function “skip_no_probe_record_support” before proceeding
With using probe point via perf builtin record.

With the change,

 82: Use vfs_getname probe to get syscall args filenames             :
--- start ---
test child forked, pid 305014
Recording open file:
libtraceevent is necessary for tracepoint support
test child finished with -2
---- end ----
Use vfs_getname probe to get syscall args filenames: Skip

 81: probe libc's inet_pton & backtrace it with ping                 :
--- start ---
test child forked, pid 305036
libtraceevent is necessary for tracepoint support
test child finished with -2
---- end ----
probe libc's inet_pton & backtrace it with ping: Skip

Signed-off-by: Athira Rajeev <[email-masked]>
---
 tools/perf/tests/shell/lib/probe_vfs_getname.sh           | 8 ++++++++
 tools/perf/tests/shell/record+probe_libc_inet_pton.sh     | 6 ++++++
 tools/perf/tests/shell/record+script_probe_vfs_getname.sh | 3 +++
 3 files changed, 17 insertions(+)

diff --git a/tools/perf/tests/shell/lib/probe_vfs_getname.sh b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
index ed0a3972c4c8..60c5e34f90c4 100644
--- a/tools/perf/tests/shell/lib/probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
@@ -22,3 +22,11 @@ skip_if_no_debuginfo() {
 	add_probe_vfs_getname -v 2>&1 | grep -E -q "^(Failed to find the path for the kernel|Debuginfo-analysis is not supported)|(file has no debug information)" && return 2
 	return 1
 }
+
+# check if perf is compiled with libtraceevent support
+skip_no_probe_record_support() {
+	if [ $had_vfs_getname -eq 1 ] ; then
+		perf record --dry-run -e $1 2>&1 | grep "libtraceevent is necessary for tracepoint support" && return 2
+		return 1
+	fi
+}
diff --git a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
index 08cdd902d0cf..b4149b2db4c6 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -11,6 +11,7 @@
 # Arnaldo Carvalho de Melo <[email-masked]>, 2017
 
 . $(dirname $0)/lib/probe.sh
+. $(dirname $0)/lib/probe_vfs_getname.sh
 
 libc=$(grep -w libc /proc/self/maps | head -1 | sed -r 's/.*[[:space:]](\/.*)/\1/g')
 nm -Dg $libc 2>/dev/null | fgrep -q inet_pton || exit 254
@@ -57,6 +58,11 @@ trace_libc_inet_pton_backtrace() {
 
 	perf_data=`mktemp -u /tmp/perf.data.XXX`
 	perf_script=`mktemp -u /tmp/perf.script.XXX`
+
+	# Check presence of libtraceevent support to run perf record
+	skip_no_probe_record_support "$event_name/$eventattr/"
+	[ $? -eq 2 ] && return 2
+
 	perf record -e $event_name/$eventattr/ -o $perf_data ping -6 -c 1 ::1 > /dev/null 2>&1
 	# check if perf data file got created in above step.
 	if [ ! -e $perf_data ]; then
diff --git a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
index 7f83b2715b9a..1341437e1bd9 100755
--- a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
@@ -17,6 +17,9 @@ skip_if_no_perf_probe || exit 2
 
 record_open_file() {
 	echo "Recording open file:"
+	# Check presence of libtraceevent support to run perf record
+	skip_no_probe_record_support "probe:vfs_getname*"
+	[ $? -eq 2 ] && return 2
 	perf record -o ${perfdata} -e probe:vfs_getname\* touch $file
 }
 
-- 
2.39.0