how to find ChunkWriteTimeout

self-finding-error-string.patch

diff --git a/swift/common/exceptions.py b/swift/common/exceptions.py
index f3e6337..c1dbea4 100644
--- a/swift/common/exceptions.py
+++ b/swift/common/exceptions.py
@@ -126,7 +126,22 @@ class ChunkReadTimeout(Timeout):
 
 
 class ChunkWriteTimeout(Timeout):
-    pass
+
+    def __init__(self, timeout):
+        if timeout == 60:
+            stack = []
+            import inspect
+            frame = inspect.currentframe()
+            while frame.f_back and len(stack) < 30:
+                stack.append(str(frame.f_code))
+                frame = frame.f_back
+            self.stack = stack
+        super(ChunkWriteTimeout, self).__init__(timeout)
+
+    def __str__(self):
+        if hasattr(self, 'stack'):
+            return ''.join(self.stack)
+        return super(ChunkWriteTimeout, self).__str__()
 
 
 class ConnectionTimeout(Timeout):