Always check if the new frame pointer is readable.

Terminate the stack trace if it isn't.

PiperOrigin-RevId: 600839499
Change-Id: I5692fa6cb52c4c8061b4ac14d8fba70f7fbabc52

absl/debugging/internal/stacktrace_aarch64-inl.inc

@@ -122,6 +122,13 @@ static void **NextStackFrame(void **old_frame_pointer, const void *uc,
       if (pre_signal_frame_pointer >= old_frame_pointer) {
       if (pre_signal_frame_pointer >= old_frame_pointer) {
         new_frame_pointer = pre_signal_frame_pointer;
         new_frame_pointer = pre_signal_frame_pointer;
       }
       }
+  }
+#endif
+
+  // The frame pointer should be 8-byte aligned.
+  if ((reinterpret_cast<uintptr_t>(new_frame_pointer) & 7) != 0)
+    return nullptr;
+
   // Check that alleged frame pointer is actually readable. This is to
   // Check that alleged frame pointer is actually readable. This is to
   // prevent "double fault" in case we hit the first fault due to e.g.
   // prevent "double fault" in case we hit the first fault due to e.g.
   // stack corruption.
   // stack corruption.
@@ -129,12 +136,6 @@ static void **NextStackFrame(void **old_frame_pointer, const void *uc,
           new_frame_pointer))
           new_frame_pointer))
     return nullptr;
     return nullptr;
   }
   }
-  }
-#endif
-
-  // The frame pointer should be 8-byte aligned.
-  if ((reinterpret_cast<uintptr_t>(new_frame_pointer) & 7) != 0)
-    return nullptr;
 
 
   // Only check the size if both frames are in the same stack.
   // Only check the size if both frames are in the same stack.
   if (InsideSignalStack(new_frame_pointer, stack_info) ==
   if (InsideSignalStack(new_frame_pointer, stack_info) ==