[PATCH v6 21/26] perf test probe_vfs_getname: Scope probe name to PID and make non-exclusive

[Ian Rogers]

The fixed vfs_getname probe name collides between parallel tests, and the
cleanup deletes every probe:vfs_getname* probe. Name the probe
getname_flags_$$, match it exactly, and remove it from an exit trap. Not
starting with vfs_getname also stops perf trace, which opens every
probe:vfs_getname* event, from pinning it.

Remove the exclusive tag from probe_vfs_getname.sh and
record+script_probe_vfs_getname.sh. trace+probe_vfs_getname.sh needs perf
trace to find its probe, so it uses vfs_getname_$$ and stays exclusive.

Assisted-by: Antigravity:gemini-3.1-pro
Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 .../perf/tests/shell/lib/probe_vfs_getname.sh | 25 ++++++++++++++++---
 tools/perf/tests/shell/probe_vfs_getname.sh   |  3 +--
 .../shell/record+script_probe_vfs_getname.sh  | 16 +++++++++---
 .../tests/shell/trace+probe_vfs_getname.sh    |  5 ++++
 4 files changed, 39 insertions(+), 10 deletions(-)

diff --git a/tools/perf/tests/shell/lib/probe_vfs_getname.sh b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
index a4230a83bcae..57a59ae7d4ae 100644
--- a/tools/perf/tests/shell/lib/probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/lib/probe_vfs_getname.sh
@@ -1,15 +1,32 @@
 #!/bin/bash
 # Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>, 2017
 
-perf probe -l 2>&1 | grep -q probe:vfs_getname
+# Scoped to the pid for parallel runs, and not "vfs_getname*" so that perf
+# trace's probe:vfs_getname* wildcard doesn't open, and so pin, the probe.
+: "${vfs_getname:=getname_flags_$$}"
+
+# The probes added, including _1, _2... for inlined copies of getname_flags.
+probes_vfs_getname() {
+	perf probe -l 2>/dev/null | awk '{print $1}' |
+		grep -E "^probe:${vfs_getname}(_[[:digit:]]+)?$"
+}
+
+probes_vfs_getname > /dev/null
 had_vfs_getname=$?
 
 cleanup_probe_vfs_getname() {
 	if [ $had_vfs_getname -eq 1 ] ; then
-		perf probe -q -d probe:vfs_getname*
+		local probe
+		for probe in $(probes_vfs_getname); do
+			perf probe -q -d "$probe"
+		done
 	fi
 }
 
+# A pid scoped probe is never reused, so remove it however the test exits.
+trap cleanup_probe_vfs_getname exit
+trap 'exit 1' term int
+
 add_probe_vfs_getname() {
 	add_probe_verbose=$1
 	if [ $had_vfs_getname -eq 1 ] ; then
@@ -41,8 +58,8 @@ add_probe_vfs_getname() {
 			return 2
 		fi
 
-		perf probe -q       "vfs_getname=${func}:${line} pathname=result->name:string" || \
-		perf probe $add_probe_verbose "vfs_getname=${func}:${line} pathname=filename:ustring" || return 1
+		perf probe -q       "${vfs_getname}=${func}:${line} pathname=result->name:string" || \
+		perf probe $add_probe_verbose "${vfs_getname}=${func}:${line} pathname=filename:ustring" || return 1
 	fi
 }
 
diff --git a/tools/perf/tests/shell/probe_vfs_getname.sh b/tools/perf/tests/shell/probe_vfs_getname.sh
index 36dc319eea0e..c40e5f3f0825 100755
--- a/tools/perf/tests/shell/probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/probe_vfs_getname.sh
@@ -1,6 +1,5 @@
 #!/bin/bash
-# Add vfs_getname probe to get syscall args filenames (exclusive)
-
+# Add vfs_getname probe to get syscall args filenames
 # SPDX-License-Identifier: GPL-2.0
 # Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>, 2017
 
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 ce20663601dc..16dbbcfc0e40 100755
--- a/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/record+script_probe_vfs_getname.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-# Use vfs_getname probe to get syscall args filenames (exclusive)
+# Use vfs_getname probe to get syscall args filenames
 
 # Uses the 'perf test shell' library to add probe:vfs_getname to the system
 # then use it with 'perf record' using 'touch' to write to a temp file, then
@@ -15,22 +15,30 @@ skip_if_no_perf_probe || exit 2
 [ "$(id -u)" = 0 ] || exit 2
 
 . "$(dirname "$0")/lib/probe_vfs_getname.sh"
+# shellcheck disable=SC2154 # vfs_getname is assigned in lib/probe_vfs_getname.sh
 
 record_open_file() {
 	echo "Recording open file:"
 	# Check presence of libtraceevent support to run perf record
-	skip_no_probe_record_support "probe:vfs_getname*"
+	skip_no_probe_record_support
 	if [ $? -eq 2 ]; then
 		echo "WARN: Skipping test record_open_file. No libtraceevent support"
 		return 2
 	fi
-	perf record -o ${perfdata} -e probe:vfs_getname\* touch $file
+	# Name the probes, a "${vfs_getname}*" glob would match longer pids.
+	local events
+	events=$(probes_vfs_getname | paste -sd, -)
+	if [ -z "${events}" ] ; then
+		echo "FAIL: no ${vfs_getname} probe to record"
+		return 1
+	fi
+	perf record -o ${perfdata} -e "${events}" touch $file
 }
 
 perf_script_filenames() {
 	echo "Looking at perf.data file for vfs_getname records for the file we touched:"
 	perf script -i ${perfdata} | \
-	grep -E " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:vfs_getname[_0-9]*: +\([[:xdigit:]]+\) +pathname=\"${file}\""
+	grep -E " +touch +[0-9]+ +\[[0-9]+\] +[0-9]+\.[0-9]+: +probe:${vfs_getname}(_[0-9]+)?: +\([[:xdigit:]]+\) +pathname=\"${file}\""
 }
 
 add_probe_vfs_getname
diff --git a/tools/perf/tests/shell/trace+probe_vfs_getname.sh b/tools/perf/tests/shell/trace+probe_vfs_getname.sh
index 28d3aa8a9e33..ab13801d9e99 100755
--- a/tools/perf/tests/shell/trace+probe_vfs_getname.sh
+++ b/tools/perf/tests/shell/trace+probe_vfs_getname.sh
@@ -10,12 +10,17 @@
 # SPDX-License-Identifier: GPL-2.0
 # Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>, 2017
 
+# Exclusive as, without BPF, any perf trace opens all probe:vfs_getname* events
+# and so would pin this test's probe.
+
 . "$(dirname $0)"/lib/probe.sh
 
 skip_if_no_perf_probe || exit 2
 skip_if_no_perf_trace || exit 2
 [ "$(id -u)" = 0 ] || exit 2
 
+# shellcheck disable=SC2034 # consumed by lib/probe_vfs_getname.sh
+vfs_getname="vfs_getname_$$"
 . "$(dirname $0)"/lib/probe_vfs_getname.sh
 
 trace_open_vfs_getname() {
-- 
2.56.0.rc1.315.gc6ed9934b7-goog