Issue in StackwalkerAMD64::GetCallerByFramePointerRecovery.

src/processor/stackwalker_amd64.h

Index: src/processor/stackwalker_amd64.h
diff --git a/src/processor/stackwalker_amd64.h b/src/processor/stackwalker_amd64.h
index 8f3dbd528024b03e7c91d74548929316d8622810..67c455104832d9353d160ed2fea4d3ea671818a4 100644
--- a/src/processor/stackwalker_amd64.h
+++ b/src/processor/stackwalker_amd64.h
@@ -78,6 +78,14 @@ class StackwalkerAMD64 : public Stackwalker {
   StackFrameAMD64* GetCallerByCFIFrameInfo(const vector<StackFrame*> &frames,
                                            CFIFrameInfo* cfi_frame_info);
 
+  // Checks whether end-of-stack is reached.  An instruction address of 0 is an
+  // end-of-stack marker.  If the stack pointer of the caller is at a lower
+  // address than the stack pointer of the callee, then that's clearly incorrect
+  // and it is treated as end-of-stack to enforce progress and avoid infinite
+  // loops.
+  bool IsEndOfStack(uint64_t caller_rip, uint64_t caller_rsp,
+                    uint64_t callee_rsp);
+
   // Assumes a traditional frame layout where the frame pointer has not been
   // omitted. The expectation is that caller's %rbp is pushed to the stack
   // after the return address of the callee, and that the callee's %rsp can