Fix race conditions in vespalib::GenerationHandler discovered by thread sanitizer.

2 files changed, 7 insertions, 7 deletions

diff --git a/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp b/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp
index 07805a6942c..f269fe729fa 100644
--- a/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp
+++ b/vespalib/src/tests/util/generationhandler/generationhandler_test.cpp
@@ -97,18 +97,18 @@ Test::requireThatTheFirstUsedGenerationIsCorrect()
     {
         GenGuard g1 = gh.takeGuard();
         gh.incGeneration();
-        EXPECT_EQUAL(true, gh.hasReaders());
+        EXPECT_EQUAL(1u, gh.getGenerationRefCount());
         EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
     }
     EXPECT_EQUAL(1u, gh.getFirstUsedGeneration());
     gh.updateFirstUsedGeneration();	// Only writer should call this
-    EXPECT_EQUAL(false, gh.hasReaders());
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount());
     EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
     {
         GenGuard g1 = gh.takeGuard();
         gh.incGeneration();
         gh.incGeneration();
-        EXPECT_EQUAL(true, gh.hasReaders());
+        EXPECT_EQUAL(1u, gh.getGenerationRefCount());
         EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
         {
             GenGuard g2 = gh.takeGuard();
@@ -117,7 +117,7 @@ Test::requireThatTheFirstUsedGenerationIsCorrect()
     }
     EXPECT_EQUAL(2u, gh.getFirstUsedGeneration());
     gh.updateFirstUsedGeneration();	// Only writer should call this
-    EXPECT_EQUAL(false, gh.hasReaders());
+    EXPECT_EQUAL(0u, gh.getGenerationRefCount());
     EXPECT_EQUAL(4u, gh.getFirstUsedGeneration());
 }
 
diff --git a/vespalib/src/tests/util/generationhandler_stress/generation_handler_stress_test.cpp b/vespalib/src/tests/util/generationhandler_stress/generation_handler_stress_test.cpp
index 8cea96e0f68..fa2c525b518 100644
--- a/vespalib/src/tests/util/generationhandler_stress/generation_handler_stress_test.cpp
+++ b/vespalib/src/tests/util/generationhandler_stress/generation_handler_stress_test.cpp
@@ -13,7 +13,7 @@ using vespalib::ThreadStackExecutor;
 
 struct WorkContext
 {
-    uint64_t _generation;
+    std::atomic<uint64_t> _generation;
 
     WorkContext() noexcept
         : _generation(0)
@@ -84,7 +84,7 @@ Fixture::readWork(const WorkContext &context)
 
     for (i = 0; i < cnt && _stopRead.load() == 0; ++i) {
         auto guard = _generationHandler.takeGuard();
-        auto generation = context._generation;
+        auto generation = context._generation.load(std::memory_order_relaxed);
         EXPECT_GREATER_EQUAL(generation, guard.getGeneration());
     }
     _doneReadWork += i;
@@ -96,7 +96,7 @@ void
 Fixture::writeWork(uint32_t cnt, WorkContext &context)
 {
     for (uint32_t i = 0; i < cnt; ++i) {
-        context._generation = _generationHandler.getNextGeneration();
+        context._generation.store(_generationHandler.getNextGeneration(), std::memory_order_relaxed);
         _generationHandler.incGeneration();
     }
     _doneWriteWork += cnt;