[PATCH net-next 0/2] selftests: net: improve error handling in passive TFO test

[PATCH net-next 0/2] selftests: net: improve error handling in passive TFO test

[Yohei Kojima]

This series improves error handling in the passive TFO test by (1)
fixing a broken behavior when the child processes failed (or timed out),
and (2) adding more error handlng code in the test program.

The first patch fixes the behavior that the test didn't report failure
even if the server or the client process exited with non-zero status.
The second patch adds error handling code in the test program to improve
reliability of the test.

This series was split out from the following series to address the
feedback from Andrew Lunn:
https://lore.kernel.org/netdev/cover.1767032397.git.yk@y-koj.net/

Yohei Kojima (2):
  selftests: net: fix passive TFO test to fail if child processes failed
  selftests: net: improve error handling in passive TFO test

 tools/testing/selftests/net/tfo.c          | 10 +++++++---
 tools/testing/selftests/net/tfo_passive.sh | 13 ++++++++++++-
 2 files changed, 19 insertions(+), 4 deletions(-)

-- 
2.52.0

[PATCH net-next 1/2] selftests: net: fix passive TFO test to fail if child processes failed

[Yohei Kojima]

This commit improves the passive TFO test to report failure if the
server or the cliend timed out or exited with non-zero status.

Before this commit, TFO test didn't fail even if exit(EXIT_FAILURE) is
added to the first line of the run_server() and run_client() functions.

Signed-off-by: Yohei Kojima <yk@y-koj.net>
---
 tools/testing/selftests/net/tfo_passive.sh | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/tfo_passive.sh b/tools/testing/selftests/net/tfo_passive.sh
index a4550511830a..f116f888b794 100755
--- a/tools/testing/selftests/net/tfo_passive.sh
+++ b/tools/testing/selftests/net/tfo_passive.sh
@@ -85,12 +85,15 @@ timeout -k 1s 30s ip netns exec nssv ./tfo        \
 				-s                \
 				-p ${SERVER_PORT} \
 				-o ${out_file}&
+server_pid="$!"
 
 wait_local_port_listen nssv ${SERVER_PORT} tcp
 
 ip netns exec nscl ./tfo -c -h ${SERVER_IP} -p ${SERVER_PORT}
+client_exit_status="$?"
 
-wait
+wait "$server_pid"
+server_exit_status="$?"
 
 res=$(cat $out_file)
 rm $out_file
@@ -101,6 +104,14 @@ if [ "$res" = "0" ]; then
 	exit 1
 fi
 
+if [ "$client_exit_status" -ne 0 ] || [ "$server_exit_status" -ne 0 ]; then
+	# Note: timeout(1) exits with 124 if it timed out
+	echo "client exited with ${client_exit_status}"
+	echo "server exited with ${server_exit_status}"
+	cleanup_ns
+	exit 1
+fi
+
 echo "$NSIM_SV_FD:$NSIM_SV_IFIDX" > $NSIM_DEV_SYS_UNLINK
 
 echo $NSIM_CL_ID > $NSIM_DEV_SYS_DEL
-- 
2.52.0

[PATCH net-next 2/2] selftests: net: improve error handling in passive TFO test

[Yohei Kojima]

This commit improves the error handling in passive TFO test to check the
return value from sendto(), and  to fail if read() failed.

Signed-off-by: Yohei Kojima <yk@y-koj.net>
---
 tools/testing/selftests/net/tfo.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/net/tfo.c b/tools/testing/selftests/net/tfo.c
index 8d82140f0f76..4572eb9b8968 100644
--- a/tools/testing/selftests/net/tfo.c
+++ b/tools/testing/selftests/net/tfo.c
@@ -82,7 +82,8 @@ static void run_server(void)
 		error(1, errno, "getsockopt(SO_INCOMING_NAPI_ID)");
 
 	if (read(connfd, buf, 64) < 0)
-		perror("read()");
+		error(1, errno, "read()");
+
 	fprintf(outfile, "%d\n", opt);
 
 	fclose(outfile);
@@ -92,14 +93,17 @@ static void run_server(void)
 
 static void run_client(void)
 {
-	int fd;
+	int fd, ret;
 	char *msg = "Hello, world!";
 
 	fd = socket(AF_INET6, SOCK_STREAM, 0);
 	if (fd == -1)
 		error(1, errno, "socket()");
 
-	sendto(fd, msg, strlen(msg), MSG_FASTOPEN, (struct sockaddr *)&cfg_addr, sizeof(cfg_addr));
+	ret = sendto(fd, msg, strlen(msg), MSG_FASTOPEN,
+		     (struct sockaddr *)&cfg_addr, sizeof(cfg_addr));
+	if (ret < 0)
+		error(1, errno, "sendto()");
 
 	close(fd);
 }
-- 
2.52.0

Re: [PATCH net-next 2/2] selftests: net: improve error handling in passive TFO test

[Markus Elfring]

> This commit improves the error handling in …

See also once more:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc4#n94

Regards,
Markus

Re: [PATCH net-next 2/2] selftests: net: improve error handling in passive TFO test

[Yohei Kojima]

On Mon, Jan 12, 2026 at 08:55:10PM +0100, Markus Elfring wrote:
> > This commit improves the error handling in …
> 
> See also once more:
> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/Documentation/process/submitting-patches.rst?h=v6.19-rc4#n94

Thank you for the feedback. I will rephrase the patch description in
imperative mood as suggested.

(I also found a typo "cliend", which will be fixed in v2 too.)

> 
> Regards,
> Markus

Re: [PATCH net-next 2/2] selftests: net: improve error handling in passive TFO test

[Markus Elfring]

> This commit improves the error handling in passive TFO test to check the
> return value from … and  to fail if read() failed.

Would any developers and system testers like to care more also for data output failures?
https://elixir.bootlin.com/linux/v6.19-rc4/source/tools/testing/selftests/net/tfo.c#L86-L88
https://cwe.mitre.org/data/definitions/252.html

Regards,
Markus

Re: [PATCH net-next 2/2] selftests: net: improve error handling in passive TFO test

[Yohei Kojima]

On Tue, Jan 13, 2026 at 10:46:10AM +0100, Markus Elfring wrote:
> > This commit improves the error handling in passive TFO test to check the
> > return value from … and  to fail if read() failed.
> 
> Would any developers and system testers like to care more also for data output failures?
> https://elixir.bootlin.com/linux/v6.19-rc4/source/tools/testing/selftests/net/tfo.c#L86-L88
> https://cwe.mitre.org/data/definitions/252.html

That's right. Although we can assume that fprintf() usually succeeds,
it worth checking its return value as tfo_passive.sh relies on the
content of the output.

I posted the v2 series adding fprintf() error handling here:
https://lore.kernel.org/netdev/cover.1768312014.git.yk@y-koj.net/

Thank you,
Yohei

> 
> Regards,
> Markus