Merge branch 'selftests-xsk-stabilize-timeout-test-behavior'

Tushar Vyavahare says:

====================
selftests/xsk: stabilize timeout test behavior

This series improves AF_XDP selftests by making timeout handling
explicit and fixing sources of non-determinism in xsk timeout tests.

Patch 1 introduces test_spec::poll_tmout and removes implicit
dependence on RX UMEM setup state for timeout behavior.

Patch 2 fixes thread harness sequencing by attaching XDP programs
before worker startup, removing signal-based termination, and using
barrier synchronization only for dual-thread runs.

Patch 3 restores shared_umem after POLL_TXQ_FULL so test-local
configuration does not leak into subsequent cases on shared-netdev
runs.

Together these changes make timeout handling easier to follow and
improve selftest stability, especially on real NIC runs.
====================

Link: https://patch.msgid.link/20260616154955.1492560-1-tushar.vyavahare@intel.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

tools/testing/selftests/bpf/prog_tests/test_xsk.c

@@ -7,7 +7,6 @@
 #include <linux/netdev.h>
 #include <poll.h>
 #include <pthread.h>
-#include <signal.h>
 #include <string.h>
 #include <sys/mman.h>
 #include <sys/socket.h>
@@ -65,11 +64,6 @@ static void gen_eth_hdr(struct xsk_socket_info *xsk, struct ethhdr *eth_hdr)
 	eth_hdr->h_proto = htons(ETH_P_LOOPBACK);
 }
 
-static bool is_umem_valid(struct xsk_socket_info *xsk)
-{
-	return !!xsk->umem->umem;
-}
-
 static u32 mode_to_xdp_flags(enum test_mode mode)
 {
 	return (mode == TEST_MODE_SKB) ? XDP_FLAGS_SKB_MODE : XDP_FLAGS_DRV_MODE;
@@ -1010,7 +1004,7 @@ static int __receive_pkts(struct test_spec *test, struct xsk_socket_info *xsk)
 			return TEST_FAILURE;
 
 		if (!ret) {
-			if (!is_umem_valid(test->ifobj_tx->xsk))
+			if (test->poll_tmout)
 				return TEST_PASS;
 
 			ksft_print_msg("ERROR: [%s] Poll timed out\n", __func__);
@@ -1149,7 +1143,7 @@ static int receive_pkts(struct test_spec *test)
 			break;
 
 		res = __receive_pkts(test, xsk);
-		if (!(res == TEST_PASS || res == TEST_CONTINUE))
+		if (res != TEST_CONTINUE)
 			return res;
 
 		ret = gettimeofday(&tv_now, NULL);
@@ -1166,7 +1160,8 @@ static int receive_pkts(struct test_spec *test)
 	return TEST_PASS;
 }
 
-static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk, bool timeout)
+static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk,
+		       bool test_timeout)
 {
 	u32 i, idx = 0, valid_pkts = 0, valid_frags = 0, buffer_len;
 	struct pkt_stream *pkt_stream = xsk->pkt_stream;
@@ -1178,7 +1173,7 @@ static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk, b
 	buffer_len = pkt_get_buffer_len(umem, pkt_stream->max_pkt_len);
 	/* pkts_in_flight might be negative if many invalid packets are sent */
 	if (pkts_in_flight >= (int)((umem_size(umem) - xsk->batch_size * buffer_len) /
-	    buffer_len)) {
+	    buffer_len) && !test_timeout) {
 		ret = kick_tx(xsk);
 		if (ret)
 			return TEST_FAILURE;
@@ -1191,7 +1186,7 @@ static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk, b
 	while (xsk_ring_prod__reserve(&xsk->tx, xsk->batch_size, &idx) < xsk->batch_size) {
 		if (use_poll) {
 			ret = poll(&fds, 1, POLL_TMOUT);
-			if (timeout) {
+			if (test_timeout) {
 				if (ret < 0) {
 					ksft_print_msg("ERROR: [%s] Poll error %d\n",
 						       __func__, errno);
@@ -1271,7 +1266,7 @@ static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk, b
 	if (use_poll) {
 		ret = poll(&fds, 1, POLL_TMOUT);
 		if (ret <= 0) {
-			if (ret == 0 && timeout)
+			if (ret == 0 && test_timeout)
 				return TEST_PASS;
 
 			ksft_print_msg("ERROR: [%s] Poll error %d\n", __func__, ret);
@@ -1279,14 +1274,14 @@ static int __send_pkts(struct ifobject *ifobject, struct xsk_socket_info *xsk, b
 		}
 	}
 
-	if (!timeout) {
+	if (!test_timeout) {
 		if (complete_pkts(xsk, i))
 			return TEST_FAILURE;
 
 		usleep(10);
-		return TEST_PASS;
 	}
 
+	/* Loop completion is driven by send_pkts() stream progress checks. */
 	return TEST_CONTINUE;
 }
 
@@ -1322,7 +1317,6 @@ bool all_packets_sent(struct test_spec *test, unsigned long *bitmap)
 
 static int send_pkts(struct test_spec *test, struct ifobject *ifobject)
 {
-	bool timeout = !is_umem_valid(test->ifobj_rx->xsk);
 	DECLARE_BITMAP(bitmap, test->nb_sockets);
 	u32 i, ret;
 
@@ -1337,19 +1331,18 @@ static int send_pkts(struct test_spec *test, struct ifobject *ifobject)
 				__set_bit(i, bitmap);
 				continue;
 			}
-			ret = __send_pkts(ifobject, &ifobject->xsk_arr[i], timeout);
-			if (ret == TEST_CONTINUE && !test->fail)
-				continue;
-
-			if ((ret || test->fail) && !timeout)
-				return TEST_FAILURE;
-
-			if (ret == TEST_PASS && timeout)
+			ret = __send_pkts(ifobject, &ifobject->xsk_arr[i], test->poll_tmout);
+			if (ret != TEST_CONTINUE)
 				return ret;
 
-			ret = wait_for_tx_completion(&ifobject->xsk_arr[i]);
-			if (ret)
+			if (test->fail)
 				return TEST_FAILURE;
+
+			if (!test->poll_tmout) {
+				ret = wait_for_tx_completion(&ifobject->xsk_arr[i]);
+				if (ret)
+					return TEST_FAILURE;
+			}
 		}
 	}
 
@@ -1677,7 +1670,8 @@ void *worker_testapp_validate_rx(void *arg)
 				       strerror(-err));
 	}
 
-	pthread_barrier_wait(&barr);
+	if (test->use_barrier)
+		pthread_barrier_wait(&barr);
 
 	/* We leave only now in case of error to avoid getting stuck in the barrier */
 	if (err) {
@@ -1716,11 +1710,6 @@ static void testapp_clean_xsk_umem(struct ifobject *ifobj)
 	munmap(umem->buffer, umem->mmap_size);
 }
 
-static void handler(int signum)
-{
-	pthread_exit(NULL);
-}
-
 static bool xdp_prog_changed_rx(struct test_spec *test)
 {
 	struct ifobject *ifobj = test->ifobj_rx;
@@ -1825,9 +1814,18 @@ static int __testapp_validate_traffic(struct test_spec *test, struct ifobject *i
 		return TEST_FAILURE;
 	}
 
-	if (ifobj2) {
+	err = xsk_attach_xdp_progs(test, ifobj1, ifobj2);
+	if (err) {
+		ksft_print_msg("Error: failed to attach XDP programs: %d (%s)\n",
+			       err, strerror(-err));
+		return TEST_FAILURE;
+	}
+	test->use_barrier = !!ifobj2;
+
+	if (test->use_barrier) {
 		if (pthread_barrier_init(&barr, NULL, 2))
 			return TEST_FAILURE;
+
 		pkt_stream_reset(ifobj2->xsk->pkt_stream);
 	}
 
@@ -1835,27 +1833,26 @@ static int __testapp_validate_traffic(struct test_spec *test, struct ifobject *i
 	pkt_stream_reset(ifobj1->xsk->pkt_stream);
 	pkts_in_flight = 0;
 
-	signal(SIGUSR1, handler);
 	/*Spawn RX thread */
 	pthread_create(&t0, NULL, ifobj1->func_ptr, test);
 
-	if (ifobj2) {
+	if (test->use_barrier) {
 		pthread_barrier_wait(&barr);
 		if (pthread_barrier_destroy(&barr)) {
-			pthread_kill(t0, SIGUSR1);
+			test->use_barrier = false;
+			pthread_join(t0, NULL);
 			clean_sockets(test, ifobj1);
 			clean_umem(test, ifobj1, NULL);
 			return TEST_FAILURE;
 		}
+	}
 
+	if (ifobj2) {
 		/*Spawn TX thread */
 		pthread_create(&t1, NULL, ifobj2->func_ptr, test);
-
 		pthread_join(t1, NULL);
 	}
 
-	if (!ifobj2)
-		pthread_kill(t0, SIGUSR1);
 	pthread_join(t0, NULL);
 
 	if (test->total_steps == test->current_step || test->fail) {
@@ -1893,8 +1890,6 @@ static int testapp_validate_traffic(struct test_spec *test)
 		}
 	}
 
-	if (xsk_attach_xdp_progs(test, ifobj_rx, ifobj_tx))
-		return TEST_FAILURE;
 	return __testapp_validate_traffic(test, ifobj_rx, ifobj_tx);
 }
 
@@ -2231,16 +2226,33 @@ int testapp_xdp_shared_umem(struct test_spec *test)
 
 int testapp_poll_txq_tmout(struct test_spec *test)
 {
+	bool shared_umem = test->ifobj_tx->shared_umem;
+	int ret;
+
+	test->poll_tmout = true;
+	/*
+	 * POLL_TXQ_FULL exercises TX timeout setup in isolation.
+	 * Keep TX out of shared-UMEM mode here so TX setup does not require
+	 * RX UMEM to be initialized first.
+	 */
+	test->ifobj_tx->shared_umem = false;
 	test->ifobj_tx->use_poll = true;
 	/* create invalid frame by set umem frame_size and pkt length equal to 2048 */
 	test->ifobj_tx->xsk->umem->frame_size = 2048;
-	if (pkt_stream_replace(test, 2 * DEFAULT_PKT_CNT, 2048))
+	if (pkt_stream_replace(test, 2 * DEFAULT_PKT_CNT, 2048)) {
+		test->ifobj_tx->shared_umem = shared_umem;
 		return TEST_FAILURE;
-	return testapp_validate_traffic_single_thread(test, test->ifobj_tx);
+	}
+
+	ret = testapp_validate_traffic_single_thread(test, test->ifobj_tx);
+	test->ifobj_tx->shared_umem = shared_umem;
+
+	return ret;
 }
 
 int testapp_poll_rxq_tmout(struct test_spec *test)
 {
+	test->poll_tmout = true;
 	test->ifobj_rx->use_poll = true;
 	return testapp_validate_traffic_single_thread(test, test->ifobj_rx);
 }

tools/testing/selftests/bpf/prog_tests/test_xsk.h

@@ -207,6 +207,8 @@ struct test_spec {
 	bool set_ring;
 	bool adjust_tail;
 	bool adjust_tail_support;
+	bool poll_tmout;
+	bool use_barrier;
 	enum test_mode mode;
 	char name[MAX_TEST_NAME_SIZE];
 };