Subject: [PATCH net-next v2 1/8] selftests: drv-net: gro: add data burst test case

From: Jakub Kicinski <[email-masked]>
Date: Thu, 2 Apr 2026 13:59:53 -0700

Add a test trying to induce a GRO context timeout followed
by another sequence of packets for the same flow. The second
burst arrives 100ms after the first one so any implementation
(SW or HW) must time out waiting at that point. We expect both
bursts to be aggregated successfully but separately.

Signed-off-by: Jakub Kicinski <[email-masked]>
---
 tools/testing/selftests/net/lib/gro.c      | 21 +++++++++++++++++++++
 tools/testing/selftests/drivers/net/gro.py |  2 +-
 2 files changed, 22 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/lib/gro.c b/tools/testing/selftests/net/lib/gro.c
index 3e611ae25f61..4d002af4a7aa 100644
--- a/tools/testing/selftests/net/lib/gro.c
+++ b/tools/testing/selftests/net/lib/gro.c
@@ -12,6 +12,7 @@
  *   - data_same:    same size packets coalesce
  *   - data_lrg_sml: large then small coalesces
  *   - data_sml_lrg: small then large doesn't coalesce
+ *   - data_burst:   two bursts of two, separated by 100ms
  *
  * ack:
  *  Pure ACK does not coalesce.
@@ -1298,6 +1299,21 @@ static void gro_sender(void)
 	} else if (strcmp(testname, "data_sml_lrg") == 0) {
 		send_data_pkts(txfd, &daddr, PAYLOAD_LEN / 2, PAYLOAD_LEN);
 		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
+	} else if (strcmp(testname, "data_burst") == 0) {
+		static char buf[MAX_HDR_LEN + PAYLOAD_LEN];
+
+		create_packet(buf, 0, 0, PAYLOAD_LEN, 0);
+		write_packet(txfd, buf, total_hdr_len + PAYLOAD_LEN, &daddr);
+		create_packet(buf, PAYLOAD_LEN, 0, PAYLOAD_LEN, 0);
+		write_packet(txfd, buf, total_hdr_len + PAYLOAD_LEN, &daddr);
+
+		usleep(100 * 1000); /* 100ms */
+		create_packet(buf, PAYLOAD_LEN * 2, 0, PAYLOAD_LEN, 0);
+		write_packet(txfd, buf, total_hdr_len + PAYLOAD_LEN, &daddr);
+		create_packet(buf, PAYLOAD_LEN * 3, 0, PAYLOAD_LEN, 0);
+		write_packet(txfd, buf, total_hdr_len + PAYLOAD_LEN, &daddr);
+
+		write_packet(txfd, fin_pkt, total_hdr_len, &daddr);
 
 	/* ack test */
 	} else if (strcmp(testname, "ack") == 0) {
@@ -1463,6 +1479,11 @@ static void gro_receiver(void)
 		correct_payload[0] = PAYLOAD_LEN / 2;
 		correct_payload[1] = PAYLOAD_LEN;
 		check_recv_pkts(rxfd, correct_payload, 2);
+	} else if (strcmp(testname, "data_burst") == 0) {
+		printf("two bursts of two data packets: ");
+		correct_payload[0] = PAYLOAD_LEN * 2;
+		correct_payload[1] = PAYLOAD_LEN * 2;
+		check_recv_pkts(rxfd, correct_payload, 2);
 
 	/* ack test */
 	} else if (strcmp(testname, "ack") == 0) {
diff --git a/tools/testing/selftests/drivers/net/gro.py b/tools/testing/selftests/drivers/net/gro.py
index 70709bf670c7..10da5d4bee9b 100755
--- a/tools/testing/selftests/drivers/net/gro.py
+++ b/tools/testing/selftests/drivers/net/gro.py
@@ -289,7 +289,7 @@ def _run_gro_bin(cfg, test_name, protocol=None, num_flows=None,
 
     # Tests that work for all protocols
     common_tests = [
-        "data_same", "data_lrg_sml", "data_sml_lrg",
+        "data_same", "data_lrg_sml", "data_sml_lrg", "data_burst",
         "ack",
         "flags_psh", "flags_syn", "flags_rst", "flags_urg", "flags_cwr",
         "tcp_csum", "tcp_seq", "tcp_ts", "tcp_opt",
-- 
2.53.0