diff --git a/src/core/util/DwarfReader.cc b/src/core/util/DwarfReader.cc
index aa7f612f..2a3bca1d 100644
--- a/src/core/util/DwarfReader.cc
+++ b/src/core/util/DwarfReader.cc
@@ -234,7 +234,7 @@ bool DwarfReader::read_mapping(std::string fileName, std::list<addrToLine>& addr
 			}
 
 			if (lineNo&&isCode) {
-				struct addrToLine newLine = { (int) addr, (int) lineNo, normalize(lineSource) };
+				struct addrToLine newLine = { addr, lineNo, normalize(lineSource) };
 				addrToLineList.push_back(newLine);
 			}
 
diff --git a/src/core/util/DwarfReader.hpp b/src/core/util/DwarfReader.hpp
index bda3dc2e..7cbbda4d 100644
--- a/src/core/util/DwarfReader.hpp
+++ b/src/core/util/DwarfReader.hpp
@@ -16,8 +16,8 @@ namespace fail {
 */
 
 	struct addrToLine {
-		int absoluteAddr;
-		int lineNumber;
+		unsigned absoluteAddr;
+		unsigned lineNumber;
 		std::string lineSource;
 	};
 
diff --git a/tools/import-trace/ElfImporter.cc b/tools/import-trace/ElfImporter.cc
index 0056c03a..87d24f1b 100644
--- a/tools/import-trace/ElfImporter.cc
+++ b/tools/import-trace/ElfImporter.cc
@@ -40,7 +40,7 @@ bool ElfImporter::create_database()
 	create_statement.str("");
 	create_statement << "CREATE TABLE IF NOT EXISTS objdump ("
 		"	variant_id int(11) NOT NULL,"
-		"	instr_address int(11) NOT NULL,"
+		"	instr_address int(11) UNSIGNED NOT NULL,"
 		"	opcode varchar(32) NOT NULL,"
 		"	disassemble VARCHAR(64),"
 		"	comment VARCHAR(128),"
@@ -77,8 +77,8 @@ bool ElfImporter::create_database()
 		create_statement.str("");
 		create_statement << "CREATE TABLE IF NOT EXISTS dbg_mapping ("
 			"	variant_id int(11) NOT NULL,"
-			"	instr_absolute int(11) NOT NULL,"
-			"	linenumber int(11) NOT NULL,"
+			"	instr_absolute int(11) UNSIGNED NOT NULL,"
+			"	linenumber int(11) UNSIGNED NOT NULL,"
 			"	file_id int(11) NOT NULL,"
 			"	PRIMARY KEY (variant_id, instr_absolute ,linenumber)"
 			") engine=MyISAM ";