From 5e7aa551ea3b300bd49a20221acc9721f2d991d1 Mon Sep 17 00:00:00 2001
From: sgehwolf <unknown>
Date: Mon, 23 Jul 2018 18:08:46 +0200
Subject: [PATCH] 8208091: SA: jhsdb jstack --mixed throws
 UnmappedAddressException on i686 Summary: Be sure to use the same register
 index in native and Java code. Reviewed-by: sballal, cjplummer, tbell

---
 .../jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java | 10 +++++++++-
 .../hotspot/debugger/windows/x86/WindowsX86CFrame.java | 10 +++++++++-
 2 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/agent/src/share/classes/sun/jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java b/agent/src/share/classes/sun/jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java
index 53a2e26a8..95fa38d72 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java
@@ -55,7 +55,15 @@ final public class LinuxX86CFrame extends BasicCFrame {
 
    public CFrame sender(ThreadProxy thread) {
       X86ThreadContext context = (X86ThreadContext) thread.getContext();
-      Address esp = context.getRegisterAsAddress(X86ThreadContext.ESP);
+      /*
+       * Native code fills in the stack pointer register value using index
+       * X86ThreadContext.SP.
+       * See file LinuxDebuggerLocal.c macro REG_INDEX(reg).
+       *
+       * Be sure to use SP, or UESP which is aliased to SP in Java code,
+       * for the frame pointer validity check.
+       */
+      Address esp = context.getRegisterAsAddress(X86ThreadContext.SP);
 
       if ( (ebp == null) || ebp.lessThan(esp) ) {
         return null;
diff --git a/agent/src/share/classes/sun/jvm/hotspot/debugger/windows/x86/WindowsX86CFrame.java b/agent/src/share/classes/sun/jvm/hotspot/debugger/windows/x86/WindowsX86CFrame.java
index dbc8b71f3..1d5e015e8 100644
--- a/agent/src/share/classes/sun/jvm/hotspot/debugger/windows/x86/WindowsX86CFrame.java
+++ b/agent/src/share/classes/sun/jvm/hotspot/debugger/windows/x86/WindowsX86CFrame.java
@@ -46,7 +46,15 @@ public class WindowsX86CFrame extends BasicCFrame {
 
   public CFrame sender(ThreadProxy thread) {
     X86ThreadContext context = (X86ThreadContext) thread.getContext();
-    Address esp = context.getRegisterAsAddress(X86ThreadContext.ESP);
+    /*
+     * Native code fills in the stack pointer register value using index
+     * X86ThreadContext.SP.
+     * See file sawindbg.cpp macro REG_INDEX(x).
+     *
+     * Be sure to use SP, or UESP which is aliased to SP in Java code,
+     * for the frame pointer validity check.
+     */
+    Address esp = context.getRegisterAsAddress(X86ThreadContext.SP);
 
     if ( (ebp == null) || ebp.lessThan(esp) ) {
       return null;
-- 
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