Add a lincheck test for remove in the segment list algorithm

gradle.properties

@@ -12,7 +12,7 @@ junit_version=4.12
 atomicfu_version=0.14.2
 knit_version=0.1.3
 html_version=0.6.8
-lincheck_version=2.6
+lincheck_version=2.7.1
 dokka_version=0.9.16-rdev-2-mpp-hacks
 byte_buddy_version=1.10.9
 reactor_vesion=3.2.5.RELEASE

kotlinx-coroutines-core/jvm/test/internal/SegmentBasedQueue.kt

@@ -87,8 +87,24 @@ internal class SegmentBasedQueue<T> {
     }
 
     fun checkHeadPrevIsCleaned() {
-        check(head.value.prev === null)
+        check(head.value.prev === null) { "head.prev is not null"}
     }
+
+    fun checkAllSegmentsAreNotLogicallyRemoved() {
+        var prev: OneElementSegment<T>? = null
+        var cur = head.value
+        while (true) {
+            check(!cur.logicallyRemoved || cur.isTail) {
+                "This queue contains removed segments, memory leak detected"
+            }
+            check(cur.prev === prev) {
+                "Two neighbour segments are incorrectly linked: S.next.prev != S"
+            }
+            prev = cur
+            cur = cur.next ?: return
+        }
+    }
+
 }
 
 private fun <T> createSegment(id: Long, prev: OneElementSegment<T>?) = OneElementSegment(id, prev, 0)
@@ -98,9 +114,11 @@ internal class OneElementSegment<T>(id: Long, prev: OneElementSegment<T>?, point
 
     override val maxSlots get() = 1
 
+    val logicallyRemoved get() = element.value === BROKEN
+
     fun removeSegment() {
-        element.value = BROKEN
-        onSlotCleaned()
+        val old = element.getAndSet(BROKEN)
+        if (old !== BROKEN) onSlotCleaned()
     }
 }
 

kotlinx-coroutines-core/jvm/test/linearizability/SegmentListRemoveLCStressTest.kt

@@ -0,0 +1,45 @@
+/*
+ * Copyright 2016-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+@file:Suppress("unused")
+
+package kotlinx.coroutines.linearizability
+
+import kotlinx.coroutines.*
+import kotlinx.coroutines.internal.*
+import org.jetbrains.kotlinx.lincheck.annotations.*
+import org.jetbrains.kotlinx.lincheck.annotations.Operation
+import org.jetbrains.kotlinx.lincheck.paramgen.*
+import org.jetbrains.kotlinx.lincheck.verifier.*
+import org.junit.*
+
+
+class SegmentListRemoveLCStressTest : VerifierState() {
+    private val q = SegmentBasedQueue<Int>()
+    private val segments: Array<OneElementSegment<Int>>
+
+    init {
+        segments = (0..5).map { q.enqueue(it)!! }.toTypedArray()
+        q.enqueue(6)
+    }
+
+    @Operation
+    fun removeSegment(@Param(gen = IntGen::class, conf = "1:5") index: Int) {
+        segments[index].removeSegment()
+    }
+
+    override fun extractState() = segments.map { it.logicallyRemoved }
+
+    @Validate
+    fun checkAllRemoved() {
+        q.checkHeadPrevIsCleaned()
+        q.checkAllSegmentsAreNotLogicallyRemoved()
+    }
+
+    @Test
+    fun test() = LCStressOptionsDefault()
+        .actorsBefore(0)
+        .actorsAfter(0)
+        .check(this::class)
+}