[PATCH net-next 0/3] selftests/xsk: stabilize timeout test behavior

[PATCH net-next 0/3] selftests/xsk: stabilize timeout test behavior

[Tushar Vyavahare]

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.

Tushar Vyavahare (3):
  selftests/xsk: make poll timeout mode explicit
  selftests/xsk: fix timeout thread harness sequencing
  selftests/xsk: restore shared_umem after POLL_TXQ_FULL

 .../selftests/bpf/prog_tests/test_xsk.c       | 96 +++++++++++--------
 .../selftests/bpf/prog_tests/test_xsk.h       |  2 +
 2 files changed, 56 insertions(+), 42 deletions(-)

-- 
2.43.0

[PATCH net-next 1/3] selftests/xsk: make poll timeout mode explicit

[Tushar Vyavahare]

Stop inferring timeout behavior from RX UMEM initialization state.
That ties timeout semantics to setup internals and obscures intent.

Use test_spec::poll_tmout as the explicit timeout-mode selector in
TX and RX paths.

In RX, treat poll timeout as expected only in timeout mode.
In TX, let send_pkts() own loop completion in non-timeout mode
and use __send_pkts() only for progress and timeout detection.

This makes timeout logic explicit and keeps control flow predictable.

Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com>
---
 .../selftests/bpf/prog_tests/test_xsk.c       | 44 +++++++++----------
 .../selftests/bpf/prog_tests/test_xsk.h       |  1 +
 2 files changed, 21 insertions(+), 24 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.c b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
index 72875071d4f1..ca47a16ceb1a 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
@@ -65,11 +65,6 @@ 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 +1005,7 @@ 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 +1144,7 @@ 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 +1161,8 @@ 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 +1174,7 @@ 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 +1187,7 @@ 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 +1267,7 @@ 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 +1275,14 @@ 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 +1318,6 @@ 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 +1332,18 @@ 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;
+			}
 		}
 	}
 
@@ -2231,6 +2225,7 @@ int testapp_xdp_shared_umem(struct test_spec *test)
 
 int testapp_poll_txq_tmout(struct test_spec *test)
 {
+	test->poll_tmout = true;
 	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;
@@ -2241,6 +2236,7 @@ int testapp_poll_txq_tmout(struct test_spec *test)
 
 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);
 }
diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.h b/tools/testing/selftests/bpf/prog_tests/test_xsk.h
index 4313d0d87235..20eaaa254998 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.h
+++ b/tools/testing/selftests/bpf/prog_tests/test_xsk.h
@@ -207,6 +207,7 @@ struct test_spec {
 	bool set_ring;
 	bool adjust_tail;
 	bool adjust_tail_support;
+	bool poll_tmout;
 	enum test_mode mode;
 	char name[MAX_TEST_NAME_SIZE];
 };
-- 
2.43.0

[PATCH net-next 2/3] selftests/xsk: fix timeout thread harness sequencing

[Tushar Vyavahare]

Prevent workers from running before XDP program attachment completes.
The previous ordering allowed races between worker startup and setup.

Attach XDP programs before entering traffic validation.

Remove SIGUSR1-based worker termination and use pthread_join() for
thread shutdown so blocking syscalls are not interrupted.

Use barriers only for dual-thread runs so participants match and
teardown ordering stays deterministic.

This removes setup/startup races and stabilizes harness sequencing.

Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com>
---
 .../selftests/bpf/prog_tests/test_xsk.c       | 33 ++++++++++---------
 .../selftests/bpf/prog_tests/test_xsk.h       |  1 +
 2 files changed, 18 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.c b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
index ca47a16ceb1a..d4702d2aac5e 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.c
+++ b/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>
@@ -1671,7 +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) {
@@ -1710,11 +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;
@@ -1819,9 +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);
 	}
 
@@ -1829,27 +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) {
@@ -1887,8 +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);
 }
 
diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.h b/tools/testing/selftests/bpf/prog_tests/test_xsk.h
index 20eaaa254998..03753ddc5dcd 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.h
+++ b/tools/testing/selftests/bpf/prog_tests/test_xsk.h
@@ -208,6 +208,7 @@ struct test_spec {
 	bool adjust_tail;
 	bool adjust_tail_support;
 	bool poll_tmout;
+	bool use_barrier;
 	enum test_mode mode;
 	char name[MAX_TEST_NAME_SIZE];
 };
-- 
2.43.0

[PATCH net-next 3/3] selftests/xsk: restore shared_umem after POLL_TXQ_FULL

[Tushar Vyavahare]

POLL_TXQ_FULL temporarily disables shared_umem on TX to exercise the
TX timeout path in isolation.

With shared_umem enabled, TX setup expects RX UMEM to be initialized
first and fails with: "RX UMEM is not initialized before shared-UMEM TX
setup".

Save and restore shared_umem around POLL_TXQ_FULL execution, and restore
it on both success and pkt_stream_replace() failure paths.

Also add an in-code comment explaining why shared_umem is temporarily
disabled in this test.

This keeps timeout setup local and prevents cross-test state leakage.

Signed-off-by: Tushar Vyavahare <tushar.vyavahare@intel.com>
---
 .../selftests/bpf/prog_tests/test_xsk.c       | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/test_xsk.c b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
index d4702d2aac5e..6eb9096d084c 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_xsk.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_xsk.c
@@ -2226,13 +2226,28 @@ 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)
-- 
2.43.0

Re: [PATCH net-next 0/3] selftests/xsk: stabilize timeout test behavior

[Jason Xing]

Hi Tushar,

On Tue, Jun 16, 2026 at 11:50 PM Tushar Vyavahare
<tushar.vyavahare@intel.com> wrote:
>
> 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.

net-next is closed, but in the meantime I'll review the series ASAP.

BTW, another thing about selftests I had in my mind is that are you
planning to work on this [1]?

[1]: https://lore.kernel.org/all/20260520004244.55663-1-kerneljasonxing@gmail.com/

Thanks,
Jason

>
> Tushar Vyavahare (3):
>   selftests/xsk: make poll timeout mode explicit
>   selftests/xsk: fix timeout thread harness sequencing
>   selftests/xsk: restore shared_umem after POLL_TXQ_FULL
>
>  .../selftests/bpf/prog_tests/test_xsk.c       | 96 +++++++++++--------
>  .../selftests/bpf/prog_tests/test_xsk.h       |  2 +
>  2 files changed, 56 insertions(+), 42 deletions(-)
>
> --
> 2.43.0
>
>

Re: [PATCH net-next 0/3] selftests/xsk: stabilize timeout test behavior

[Maciej Fijalkowski]

On Wed, Jun 17, 2026 at 07:39:06AM +0800, Jason Xing wrote:
> Hi Tushar,
> 
> On Tue, Jun 16, 2026 at 11:50 PM Tushar Vyavahare
> <tushar.vyavahare@intel.com> wrote:
> >
> > 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.
> 
> net-next is closed, but in the meantime I'll review the series ASAP.
> 
> BTW, another thing about selftests I had in my mind is that are you
> planning to work on this [1]?

This one is on me. I took your changes Jason and aligned ZC batching side
to this behavior, followed by xskxceiver adjustment. I am planning to send
this today EOD, however let's see how badly internal Sashiko will kick my
ass.

> 
> [1]: https://lore.kernel.org/all/20260520004244.55663-1-kerneljasonxing@gmail.com/
> 
> Thanks,
> Jason
> 
> >
> > Tushar Vyavahare (3):
> >   selftests/xsk: make poll timeout mode explicit
> >   selftests/xsk: fix timeout thread harness sequencing
> >   selftests/xsk: restore shared_umem after POLL_TXQ_FULL
> >
> >  .../selftests/bpf/prog_tests/test_xsk.c       | 96 +++++++++++--------
> >  .../selftests/bpf/prog_tests/test_xsk.h       |  2 +
> >  2 files changed, 56 insertions(+), 42 deletions(-)
> >
> > --
> > 2.43.0
> >
> >
> 

Re: [PATCH net-next 0/3] selftests/xsk: stabilize timeout test behavior

[Jason Xing]

On Wed, Jun 17, 2026 at 5:43 PM Maciej Fijalkowski
<maciej.fijalkowski@intel.com> wrote:
>
> On Wed, Jun 17, 2026 at 07:39:06AM +0800, Jason Xing wrote:
> > Hi Tushar,
> >
> > On Tue, Jun 16, 2026 at 11:50 PM Tushar Vyavahare
> > <tushar.vyavahare@intel.com> wrote:
> > >
> > > 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.
> >
> > net-next is closed, but in the meantime I'll review the series ASAP.
> >
> > BTW, another thing about selftests I had in my mind is that are you
> > planning to work on this [1]?
>
> This one is on me. I took your changes Jason and aligned ZC batching side
> to this behavior, followed by xskxceiver adjustment. I am planning to send
> this today EOD, however let's see how badly internal Sashiko will kick my
> ass.

Thanks. We'll see :)

Thanks,
Jason

>
> >
> > [1]: https://lore.kernel.org/all/20260520004244.55663-1-kerneljasonxing@gmail.com/
> >
> > Thanks,
> > Jason
> >
> > >
> > > Tushar Vyavahare (3):
> > >   selftests/xsk: make poll timeout mode explicit
> > >   selftests/xsk: fix timeout thread harness sequencing
> > >   selftests/xsk: restore shared_umem after POLL_TXQ_FULL
> > >
> > >  .../selftests/bpf/prog_tests/test_xsk.c       | 96 +++++++++++--------
> > >  .../selftests/bpf/prog_tests/test_xsk.h       |  2 +
> > >  2 files changed, 56 insertions(+), 42 deletions(-)
> > >
> > > --
> > > 2.43.0
> > >
> > >
> >