diff --git a/app/models/notice.rb b/app/models/notice.rb
index 4c578ca..1e5fa92 100644
--- a/app/models/notice.rb
+++ b/app/models/notice.rb
@@ -129,7 +129,7 @@ class Notice
       send("#{h}=",sanitize_hash(send(h)))
     end
     # Set unknown backtrace files
-    backtrace.each{|line| line['file'] = "[unknown source]" if line['file'].blank? }
+    read_attribute(:backtrace).each{|line| line['file'] = "[unknown source]" if line['file'].blank? }
   end
 
   def sanitize_hash(h)
--
libgit2 0.21.2