[PATCH v1] perf test: Fix inet_pton probe failure due to multiple probes

[PATCH v1] perf test: Fix inet_pton probe failure due to multiple probes

[Ian Rogers]

When adding a probe for libc's inet_pton, perf probe may create multiple
probe points (e.g., due to inlining or multiple symbol resolutions),
resulting in multiple identical event names being output (e.g.,
`probe_libc:inet_pton_1`).

The script previously used a brittle pipeline (`tail -n +2 | head -n -5`)
and an awk script to extract the event name. When multiple probes were
added, awk would output the event name multiple times, which expanded
to multiple words in bash. This broke the subsequent `perf record` and
`perf probe -d` commands, causing the test to fail with:
`Error: another command except --add is set.`

Fix this by removing the brittle `tail/head` commands and appending
`| sort -u` to the awk extraction. This ensures that only a single,
unique event name is captured, regardless of how many probe points
are created.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/record+probe_libc_inet_pton.sh | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

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 ab99bef556bf..b717063f70c2 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -22,9 +22,9 @@ event_pattern='probe_libc:inet_pton(_[[:digit:]]+)?'
 
 add_libc_inet_pton_event() {
 
-	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
+	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | \
 			awk -v ep="$event_pattern" -v l="$libc" '$0 ~ ep && $0 ~ \
-			("\\(on inet_pton in " l "\\)") {print $1}')
+			("\\(on inet_pton in " l "\\)") {print $1}' | sort -u)
 
 	if [ $? -ne 0 ] || [ -z "$event_name" ] ; then
 		printf "FAIL: could not add event\n"
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH v1] perf test: Fix inet_pton probe failure due to multiple probes

[sashiko-bot]

Sashiko AI review found 1 potential issue(s):
- [Medium] The use of `sort -u` fails to guarantee a single event name on systems without uprobe multiprobe support, leaving the test broken in those environments.
--

commit 82ddf08abe58056272425532334245db796f2020
Author: Ian Rogers <irogers@google.com>

perf test: Fix inet_pton probe failure due to multiple probes

This commit attempts to fix a test failure caused by perf probe outputting
multiple probe points. It replaces a tail/head pipeline with sort -u to try
and extract a single, unique event name from the awk script output.

> 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 ab99bef556bf0..b717063f70c27 100755
> --- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> +++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> @@ -22,9 +22,9 @@ event_pattern='probe_libc:inet_pton(_[[:digit:]]+)?'
>  
>  add_libc_inet_pton_event() {
>  
> -	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
> +	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | \
>  			awk -v ep="$event_pattern" -v l="$libc" '$0 ~ ep && $0 ~ \
> -			("\\(on inet_pton in " l "\\)") {print $1}')
> +			("\\(on inet_pton in " l "\\)") {print $1}' | sort -u)

Does sort -u guarantee a single event name is captured on kernels without
uprobe multiprobe support?

On systems without multiprobe support, perf probe actively prevents name
collisions by appending indices to subsequent probe points, outputting
names like probe_libc:inet_pton and probe_libc:inet_pton_1. 

Because these strings are textually distinct, sort -u will output all of
them rather than deduplicating them.

This leaves the event_name variable containing multiple words separated by
newlines. When expanded unquoted in the subsequent perf record and perf probe
commands, bash word splitting causes the same syntax errors the patch intends
to fix.

Could this use head -n 1 or awk '{print $1; exit}' instead to robustly
guarantee a single name is captured across all environments?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260410002351.10856-1-irogers@google.com?part=1

[PATCH v2] perf test: Fix inet_pton probe failure and unroll call graph

[Ian Rogers]

When adding a probe for libc's inet_pton, perf probe may create multiple
probe points (e.g., due to inlining or multiple symbol resolutions),
resulting in multiple identical event names being output (e.g.,
`probe_libc:inet_pton_1`).

The script previously used a brittle pipeline (`tail -n +2 | head -n -5`)
and an awk script to extract the event name. When multiple probes were
added, awk would output the event name multiple times, which expanded
to multiple words in bash. This broke the subsequent `perf record` and
`perf probe -d` commands, causing the test to fail with:
`Error: another command except --add is set.`

Fix this by removing the brittle `tail/head` commands and appending
`| head -n 1` to the awk extraction. This ensures that only a single,
unique event name is captured, regardless of how many probe points
are created.

Additionally, the test artificially limited the backtrace size via
`max-stack=4` and did not specify dwarf call graphs for non-s390x
architectures. In newer libc versions where `inet_pton` is nested
deeper or compiled without frame pointers, `perf script` failed to resolve
the backtrace up to `/bin/ping`. Fix this by explicitly collecting
dwarf call-graphs for all architectures and increasing `max-stack` to 8.

Assisted-by: Gemini:gemini-3.1-pro-preview
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/tests/shell/record+probe_libc_inet_pton.sh | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

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 ab99bef556bf..eca629ee83f0 100755
--- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
+++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
@@ -22,9 +22,9 @@ event_pattern='probe_libc:inet_pton(_[[:digit:]]+)?'
 
 add_libc_inet_pton_event() {
 
-	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | tail -n +2 | head -n -5 | \
+	event_name=$(perf probe -f -x $libc -a inet_pton 2>&1 | \
 			awk -v ep="$event_pattern" -v l="$libc" '$0 ~ ep && $0 ~ \
-			("\\(on inet_pton in " l "\\)") {print $1}')
+			("\\(on inet_pton in " l "\\)") {print $1}' | head -n 1)
 
 	if [ $? -ne 0 ] || [ -z "$event_name" ] ; then
 		printf "FAIL: could not add event\n"
@@ -40,12 +40,12 @@ trace_libc_inet_pton_backtrace() {
 	echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
 	case "$(uname -m)" in
 	s390x)
-		eventattr='call-graph=dwarf,max-stack=4'
+		eventattr='call-graph=dwarf,max-stack=8'
 		echo "((__GI_)?getaddrinfo|text_to_binary_address)\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
 		echo "(gaih_inet|main)\+0x[[:xdigit:]]+[[:space:]]\(inlined|.*/bin/ping.*\)$" >> $expected
 		;;
 	*)
-		eventattr='max-stack=4'
+		eventattr='call-graph=dwarf,max-stack=8'
 		echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
 		;;
 	esac
-- 
2.53.0.1213.gd9a14994de-goog

Re: [PATCH v2] perf test: Fix inet_pton probe failure and unroll call graph

[sashiko-bot]

Sashiko AI review found 1 potential issue(s):
- [Medium] Unconditionally requiring DWARF call-graphs causes the test to falsely fail on perf builds lacking DWARF support.
--

commit dbec7073d294917f7866e8ea3a6b39004a7407ad
Author: Ian Rogers <irogers@google.com>

perf test: Fix inet_pton probe failure and unroll call graph

This commit fixes an issue where multiple identical event names were output
by perf probe when creating multiple probe points, which broke subsequent
commands. It also updates the backtrace collection to explicitly request
dwarf call-graphs and increases max-stack to 8 for all architectures.

> 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 ab99bef556bf0..eca629ee83f03 100755
> --- a/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
> +++ b/tools/perf/tests/shell/record+probe_libc_inet_pton.sh
[ ... ]
> @@ -40,12 +40,12 @@ trace_libc_inet_pton_backtrace() {
>  	echo ".*inet_pton\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
>  	case "$(uname -m)" in
>  	s390x)
> -		eventattr='call-graph=dwarf,max-stack=4'
> +		eventattr='call-graph=dwarf,max-stack=8'
>  		echo "((__GI_)?getaddrinfo|text_to_binary_address)\+0x[[:xdigit:]]+[[:space:]]\($libc|inlined\)$" >> $expected
>  		echo "(gaih_inet|main)\+0x[[:xdigit:]]+[[:space:]]\(inlined|.*/bin/ping.*\)$" >> $expected
>  		;;
>  	*)
> -		eventattr='max-stack=4'
> +		eventattr='call-graph=dwarf,max-stack=8'

Will this cause the test to falsely fail on perf builds lacking DWARF support?

If perf is compiled without libunwind or libdw, running perf record with
call-graph=dwarf will exit with an error. Since the test script doesn't
appear to verify DWARF support before running, the test will report a hard
failure rather than gracefully skipping on minimal perf builds.

>  		echo ".*(\+0x[[:xdigit:]]+|\[unknown\])[[:space:]]\(.*/bin/ping.*\)$" >> $expected
>  		;;
>  	esac

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260411193705.735269-1-irogers@google.com?part=1