64 lines
2.4 KiB
Diff
64 lines
2.4 KiB
Diff
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From 06c663befa33d4a71faed3f58ae47faab753b658 Mon Sep 17 00:00:00 2001
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Date: Sat, 28 Mar 2020 12:00:06 +0000
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Subject: [PATCH] 8210303 VM_HandshakeAllThreads fails assert with "failed:
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blocked and not walkable"
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Summary: <gc>: <vmthread can process handshake in more conditions>
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LLT: jdk11u/test/hotspot/jtreg/vmTestbase/nsk/jvmti/scenarios/sampling/SP07/sp07t002/TestDescription.java
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Bug url: https://bugs.openjdk.java.net/browse/JDK-8210303
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---
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src/hotspot/share/runtime/handshake.cpp | 25 +++++++++++++++++++++++--
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1 file changed, 23 insertions(+), 2 deletions(-)
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diff --git a/src/hotspot/share/runtime/handshake.cpp b/src/hotspot/share/runtime/handshake.cpp
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index 7aac489..1891623 100644
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--- a/src/hotspot/share/runtime/handshake.cpp
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+++ b/src/hotspot/share/runtime/handshake.cpp
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@@ -1,5 +1,5 @@
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/*
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- * Copyright (c) 2017, Oracle and/or its affiliates. All rights reserved.
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+ * Copyright (c) 2017, 2018, Oracle and/or its affiliates. All rights reserved.
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* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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*
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* This code is free software; you can redistribute it and/or modify it
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@@ -343,6 +343,27 @@ bool HandshakeState::vmthread_can_process_handshake(JavaThread* target) {
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return SafepointSynchronize::safepoint_safe(target, target->thread_state());
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}
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+static bool possibly_vmthread_can_process_handshake(JavaThread* target) {
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+ // An externally suspended thread cannot be resumed while the
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+ // Threads_lock is held so it is safe.
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+ // Note that this method is allowed to produce false positives.
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+ assert(Threads_lock->owned_by_self(), "Not holding Threads_lock.");
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+ if (target->is_ext_suspended()) {
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+ return true;
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+ }
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+ switch (target->thread_state()) {
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+ case _thread_in_native:
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+ // native threads are safe if they have no java stack or have walkable stack
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+ return !target->has_last_Java_frame() || target->frame_anchor()->walkable();
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+
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+ case _thread_blocked:
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+ return true;
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+
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+ default:
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+ return false;
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+ }
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+}
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+
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bool HandshakeState::claim_handshake_for_vmthread() {
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if (!_semaphore.trywait()) {
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return false;
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@@ -362,7 +383,7 @@ void HandshakeState::process_by_vmthread(JavaThread* target) {
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return;
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}
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- if (!vmthread_can_process_handshake(target)) {
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+ if (!possibly_vmthread_can_process_handshake(target)) {
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// JT is observed in an unsafe state, it must notice the handshake itself
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return;
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}
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--
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1.8.3.1
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