diff --git a/configure.in b/configure.in
index 1447200..a3b19cf 100644
--- a/configure.in
+++ b/configure.in
@@ -11,7 +11,7 @@ AC_ARG_ENABLE(debug,
 	[ enable_debug=$enableval ],
 	[ enable_debug=no ])
 
-AM_CONDITIONAL(DEBUG, test x$enable_debug = xtrue)
+AM_CONDITIONAL(DEBUG, test x$enable_debug = xyes)
 
 case $enable_debug in
 yes)
@@ -24,11 +24,20 @@ no)
 	AC_MSG_ERROR(bad value ${enable_debug} for --enable-debug)
 esac
 
+backtrace=
+if test x$enable_debug = xyes ; then
+	AC_CHECK_FUNC(backtrace_symbols_fd, [
+		AC_DEFINE(HAVE_BACKTRACE, [], [Use Glibcs backtrace function on fatal()])
+		LDFLAGS="-rdynamic $LDFLAGS"
+		backtrace="(with backtrace)"
+	])
+fi
+
 AC_ARG_ENABLE(oidentd,
 	[  --enable-oidentd                Enable oidentd support (bip overwrites ~/.oidentd.conf with this on!)],
-enable_oidentd=yes
-AC_DEFINE([HAVE_OIDENTD], [], [Enable oidentd.conf management support]),
-[enable_oidentd=no]
+	enable_oidentd=yes
+	AC_DEFINE([HAVE_OIDENTD], [], [Enable oidentd.conf management support]),
+	[enable_oidentd=no]
 	)
 
 AM_CONDITIONAL(OIDENTD, test x$enable_identd = xyes)
@@ -39,16 +48,15 @@ AC_ARG_ENABLE(openssl,
 	      [ enable_openssl=yes ])
 
 if test "x$enable_openssl" = "xyes" ; then
-    AC_CHECK_LIB(crypto, CRYPTO_new_ex_data, [],
-		 [AC_MSG_ERROR([library 'crypto' is required for OpenSSL support])]) 
-
-    AC_CHECK_LIB(ssl, SSL_read, [], 
-		 [AC_MSG_ERROR(
-		  [library 'ssl' is required for OpenSSL support])],
-		  -lcrypto) 
+	AC_CHECK_LIB(crypto, CRYPTO_new_ex_data, [], [
+		AC_MSG_ERROR([library 'crypto' is required for OpenSSL support])
+	], -lcrypto) 
+    	AC_CHECK_LIB(ssl, SSL_read, [], [
+		AC_MSG_ERROR([library 'ssl' is required for OpenSSL support])
+	]) 
 fi
 AC_OUTPUT(Makefile src/Makefile samples/Makefile)
 
 echo OPENSSL: $enable_openssl
-echo DEBUG: $enable_debug
+echo DEBUG: $enable_debug $backtrace
 echo OIDENTD: $enable_oidentd
diff --git a/src/config.h.in b/src/config.h.in
index c27f0ea..875c464 100644
--- a/src/config.h.in
+++ b/src/config.h.in
@@ -1,5 +1,8 @@
 /* src/config.h.in.  Generated from configure.in by autoheader.  */
 
+/* Use Glibcs backtrace function on fatal() */
+#undef HAVE_BACKTRACE
+
 /* Define to 1 if you have the `crypto' library (-lcrypto). */
 #undef HAVE_LIBCRYPTO
 
diff --git a/src/irc.c b/src/irc.c
index 800bd87..9b45fae 100644
--- a/src/irc.c
+++ b/src/irc.c
@@ -1631,7 +1631,7 @@ static int irc_mode(struct link_server *server, struct line *line)
 			if (!hash_includes(&channel->ovmasks, nick))
 				return ERR_PROTOCOL;
 
-			ovmask = (long int)hash_get(&channel->ovmasks, nick);
+			ovmask = (long int)hash_remove(&channel->ovmasks, nick);
 			if (add)
 				ovmask |= NICKHALFOP;
 			else
@@ -1647,7 +1647,7 @@ static int irc_mode(struct link_server *server, struct line *line)
 			if (!hash_includes(&channel->ovmasks, nick))
 				return ERR_PROTOCOL;
 
-			ovmask = (long int)hash_get(&channel->ovmasks, nick);
+			ovmask = (long int)hash_remove(&channel->ovmasks, nick);
 			if (add)
 				ovmask |= NICKVOICED;
 			else
diff --git a/src/util.c b/src/util.c
index d7d5eec..e274102 100644
--- a/src/util.c
+++ b/src/util.c
@@ -198,15 +198,34 @@ void mylog(int level, char *fmt, ...)
 	va_end(ap);
 }
 
+#ifdef HAVE_BACKTRACE
+#include <execinfo.h>
+
+void print_trace(void)
+{
+	void *array[32];
+	size_t size;
+	size_t i;
+
+	size = backtrace(array, 32);
+	fflush(conf_global_log_file);
+	backtrace_symbols_fd(array, size, fileno(conf_global_log_file));
+}
+#endif
+
 extern char *conf_pid_file;
 void fatal(char *fmt, ...)
 {
 	va_list ap;
+
 	va_start(ap, fmt);
-
 	_mylog(LOG_FATAL, fmt, ap);
-
 	va_end(ap);
+
+#ifdef HAVE_BACKTRACE
+	print_trace();
+#endif
+
 	exit(200);
 }