diff --git a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
index 97c8f876f673..a3b82cf2f9e9 100644
--- a/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
+++ b/tools/testing/selftests/bpf/prog_tests/xdp_context_test_run.c
@@ -124,10 +124,10 @@ static int send_test_packet(int ifindex)
 	int n, sock = -1;
 	__u8 packet[sizeof(struct ethhdr) + TEST_PAYLOAD_LEN];
 
-	/* The ethernet header is not relevant for this test and doesn't need to
-	 * be meaningful.
-	 */
-	struct ethhdr eth = { 0 };
+	/* We use the Ethernet header only to identify the test packet */
+	struct ethhdr eth = {
+		.h_source = { 0x12, 0x34, 0xDE, 0xAD, 0xBE, 0xEF },
+	};
 
 	memcpy(packet, &eth, sizeof(eth));
 	memcpy(packet + sizeof(eth), test_payload, TEST_PAYLOAD_LEN);
@@ -160,8 +160,16 @@ static int write_test_packet(int tap_fd)
 	__u8 packet[sizeof(struct ethhdr) + TEST_PAYLOAD_LEN];
 	int n;
 
-	/* The ethernet header doesn't need to be valid for this test */
-	memset(packet, 0, sizeof(struct ethhdr));
+	/* The Ethernet header is mostly not relevant. We use it to identify the
+	 * test packet and some BPF helpers we exercise expect to operate on
+	 * Ethernet frames carrying IP packets. Pretend that's the case.
+	 */
+	struct ethhdr eth = {
+		.h_source = { 0x12, 0x34, 0xDE, 0xAD, 0xBE, 0xEF },
+		.h_proto = htons(ETH_P_IP),
+	};
+
+	memcpy(packet, &eth, sizeof(eth));
 	memcpy(packet + sizeof(struct ethhdr), test_payload, TEST_PAYLOAD_LEN);
 
 	n = write(tap_fd, packet, sizeof(packet));
@@ -484,6 +492,11 @@ void test_xdp_context_tuntap(void)
 			    skel->progs.helper_skb_vlan_push_pop,
 			    NULL, /* tc prio 2 */
 			    &skel->bss->test_pass);
+	if (test__start_subtest("helper_skb_adjust_room"))
+		test_tuntap(skel->progs.ing_xdp,
+			    skel->progs.helper_skb_adjust_room,
+			    NULL, /* tc prio 2 */
+			    &skel->bss->test_pass);
 
 	test_xdp_meta__destroy(skel);
 }
diff --git a/tools/testing/selftests/bpf/progs/test_xdp_meta.c b/tools/testing/selftests/bpf/progs/test_xdp_meta.c
index 04c7487bb350..6edc84d8dc52 100644
--- a/tools/testing/selftests/bpf/progs/test_xdp_meta.c
+++ b/tools/testing/selftests/bpf/progs/test_xdp_meta.c
@@ -20,6 +20,10 @@
 
 bool test_pass;
 
+static const __u8 smac_want[ETH_ALEN] = {
+	0x12, 0x34, 0xDE, 0xAD, 0xBE, 0xEF,
+};
+
 static const __u8 meta_want[META_SIZE] = {
 	0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07, 0x08,
 	0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17, 0x18,
@@ -27,6 +31,11 @@ static const __u8 meta_want[META_SIZE] = {
 	0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37, 0x38,
 };
 
+static bool check_smac(const struct ethhdr *eth)
+{
+	return !__builtin_memcmp(eth->h_source, smac_want, ETH_ALEN);
+}
+
 static bool check_metadata(const char *file, int line, __u8 *meta_have)
 {
 	if (!__builtin_memcmp(meta_have, meta_want, META_SIZE))
@@ -281,7 +290,7 @@ int ing_xdp_zalloc_meta(struct xdp_md *ctx)
 	/* Drop any non-test packets */
 	if (eth + 1 > ctx_ptr(ctx, data_end))
 		return XDP_DROP;
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		return XDP_DROP;
 
 	ret = bpf_xdp_adjust_meta(ctx, -META_SIZE);
@@ -321,9 +330,9 @@ int ing_xdp(struct xdp_md *ctx)
 
 	/* The Linux networking stack may send other packets on the test
 	 * interface that interfere with the test. Just drop them.
-	 * The test packets can be recognized by their ethertype of zero.
+	 * The test packets can be recognized by their source MAC address.
 	 */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		return XDP_DROP;
 
 	__builtin_memcpy(data_meta, payload, META_SIZE);
@@ -343,7 +352,7 @@ int clone_data_meta_survives_data_write(struct __sk_buff *ctx)
 	if (eth + 1 > ctx_ptr(ctx, data_end))
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	if (meta_have + META_SIZE > eth)
@@ -373,7 +382,7 @@ int clone_data_meta_survives_meta_write(struct __sk_buff *ctx)
 	if (eth + 1 > ctx_ptr(ctx, data_end))
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	if (meta_have + META_SIZE > eth)
@@ -406,7 +415,7 @@ int clone_meta_dynptr_survives_data_slice_write(struct __sk_buff *ctx)
 	if (!eth)
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	bpf_dynptr_from_skb_meta(ctx, 0, &meta);
@@ -435,7 +444,7 @@ int clone_meta_dynptr_survives_meta_slice_write(struct __sk_buff *ctx)
 	if (!eth)
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	bpf_dynptr_from_skb_meta(ctx, 0, &meta);
@@ -469,7 +478,7 @@ int clone_meta_dynptr_rw_before_data_dynptr_write(struct __sk_buff *ctx)
 	if (!eth)
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	/* Expect read-write metadata before unclone */
@@ -511,7 +520,7 @@ int clone_meta_dynptr_rw_before_meta_dynptr_write(struct __sk_buff *ctx)
 	if (!eth)
 		goto out;
 	/* Ignore non-test packets */
-	if (eth->h_proto != 0)
+	if (!check_smac(eth))
 		goto out;
 
 	/* Expect read-write metadata before unclone */
@@ -568,4 +577,38 @@ out:
 	return TC_ACT_SHOT;
 }
 
+SEC("tc")
+int helper_skb_adjust_room(struct __sk_buff *ctx)
+{
+	int err;
+
+	/* Grow a 1 byte hole after the MAC header */
+	err = bpf_skb_adjust_room(ctx, 1, BPF_ADJ_ROOM_MAC, 0);
+	if (err)
+		goto out;
+
+	if (!check_skb_metadata(ctx))
+		goto out;
+
+	/* Shrink a 1 byte hole after the MAC header */
+	err = bpf_skb_adjust_room(ctx, -1, BPF_ADJ_ROOM_MAC, 0);
+	if (err)
+		goto out;
+
+	if (!check_skb_metadata(ctx))
+		goto out;
+
+	/* Grow a 256 byte hole to trigger head reallocation */
+	err = bpf_skb_adjust_room(ctx, 256, BPF_ADJ_ROOM_MAC, 0);
+	if (err)
+		goto out;
+
+	if (!check_skb_metadata(ctx))
+		goto out;
+
+	test_pass = true;
+out:
+	return TC_ACT_SHOT;
+}
+
 char _license[] SEC("license") = "GPL";