[dpdk-dev] [PATCH v5 2/2] test/service: fix race condition on stopping lcore

[Harry van Haaren <harry.van.haaren@intel.com>]

This commit fixes a potential race condition in the tests
where the lcore running a service would increment a counter
that was already reset by the test-suite thread. The resulting
race-condition incremented value could cause CI failures, as
indicated by DPDK's CI.

This patch fixes the race-condition by making use of the
added rte_service_lcore_active() API, which indicates when
a service-core is no longer in the service-core polling loop.

The unit test makes use of the above function to detect when
all statistics increments are done in the service-core thread,
and then the unit test continues finalizing and checking state.

Fixes: f28f3594ded2 ("service: add attribute API")

Reported-by: David Marchand <david.marchand@redhat.com>
Signed-off-by: Harry van Haaren <harry.van.haaren@intel.com>
Reviewed-by: Phil Yang <phil.yang@arm.com>
Reviewed-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>

---

v4:
- Update test to new _may_be_ style API (Honnappa)
- Add reviewed by from ML

v3:
- Refactor while() to for() to simplify (Harry)
- Use SERVICE_DELAY instead of magic const 1 (Phil)
- Add Phil's reviewed by tag from ML

v2:
Thanks for discussion on v1, this v2 fixup for the CI
including previous feedback on ML.
---
 app/test/test_service_cores.c | 20 +++++++++++++++++++-
 1 file changed, 19 insertions(+), 1 deletion(-)

diff --git a/app/test/test_service_cores.c b/app/test/test_service_cores.c
index ef1d8fcb9..8bc1d9913 100644
--- a/app/test/test_service_cores.c
+++ b/app/test/test_service_cores.c
@@ -362,6 +362,9 @@ service_lcore_attr_get(void)
 			"Service core add did not return zero");
 	TEST_ASSERT_EQUAL(0, rte_service_map_lcore_set(id, slcore_id, 1),
 			"Enabling valid service and core failed");
+	/* Ensure service is not active before starting */
+	TEST_ASSERT_EQUAL(0, rte_service_lcore_may_be_active(slcore_id),
+			"Not-active service core reported as active");
 	TEST_ASSERT_EQUAL(0, rte_service_lcore_start(slcore_id),
 			"Starting service core failed");
 
@@ -382,7 +385,22 @@ service_lcore_attr_get(void)
 			lcore_attr_id, &lcore_attr_value),
 			"Invalid lcore attr didn't return -EINVAL");
 
-	rte_service_lcore_stop(slcore_id);
+	/* Ensure service is active */
+	TEST_ASSERT_EQUAL(1, rte_service_lcore_may_be_active(slcore_id),
+			"Active service core reported as not-active");
+
+	TEST_ASSERT_EQUAL(0, rte_service_map_lcore_set(id, slcore_id, 0),
+			"Disabling valid service and core failed");
+	TEST_ASSERT_EQUAL(0, rte_service_lcore_stop(slcore_id),
+			"Failed to stop service lcore");
+
+	/* Wait until service lcore not active, or for 100x SERVICE_DELAY */
+	for (int i = 0; rte_service_lcore_may_be_active(slcore_id) == 1 &&
+			i < 100; i++)
+		rte_delay_ms(SERVICE_DELAY);
+
+	TEST_ASSERT_EQUAL(0, rte_service_lcore_may_be_active(slcore_id),
+			  "Service lcore not stopped after waiting.");
 
 	TEST_ASSERT_EQUAL(0, rte_service_lcore_attr_reset_all(slcore_id),
 			  "Valid lcore_attr_reset_all() didn't return success");
-- 
2.17.1