7178741: SA: jstack -m produce UnalignedAddressException in output (Linux)

Reviewed-by: poonam, sla

agent/src/share/classes/sun/jvm/hotspot/debugger/linux/amd64/LinuxAMD64CFrame.java

@@ -60,8 +60,13 @@ final public class LinuxAMD64CFrame extends BasicCFrame {
         return null;
       }
 
+      // Check alignment of rbp
+      if ( dbg.getAddressValue(rbp) % ADDRESS_SIZE != 0) {
+        return null;
+      }
+
       Address nextRBP = rbp.getAddressAt( 0 * ADDRESS_SIZE);
-      if (nextRBP == null) {
+      if (nextRBP == null || nextRBP.lessThanOrEqual(rbp)) {
         return null;
       }
       Address nextPC  = rbp.getAddressAt( 1 * ADDRESS_SIZE);

agent/src/share/classes/sun/jvm/hotspot/debugger/linux/x86/LinuxX86CFrame.java

@@ -61,8 +61,13 @@ final public class LinuxX86CFrame extends BasicCFrame {
         return null;
       }
 
+      // Check alignment of ebp
+      if ( dbg.getAddressValue(ebp) % ADDRESS_SIZE != 0) {
+        return null;
+      }
+
       Address nextEBP = ebp.getAddressAt( 0 * ADDRESS_SIZE);
-      if (nextEBP == null) {
+      if (nextEBP == null || nextEBP.lessThanOrEqual(ebp)) {
         return null;
       }
       Address nextPC  = ebp.getAddressAt( 1 * ADDRESS_SIZE);