diff --git a/configure.ac b/configure.ac
index b8742e0..50e1549 100644
--- a/configure.ac
+++ b/configure.ac
@@ -488,6 +488,12 @@ for j in $WARNLIST; do
 	fi
 done
 
+# warnings suppression
+if test x"$GCC" = xyes && cc_supports_flag -Wsuggest-attribute=format; then
+	AC_DEFINE([HAVE_GCC_SUGGEST_ATTRIBUTE_FORMAT], [],
+		  [gcc supports -Wsuggest-attribute=format])
+fi
+
 # --- coverage ---
 if test "x${enable_coverage}" = xyes && \
 		cc_supports_flag -ftest-coverage && \
diff --git a/include/qb/qblog.h b/include/qb/qblog.h
index 042d7a0..870cbae 100644
--- a/include/qb/qblog.h
+++ b/include/qb/qblog.h
@@ -296,7 +296,8 @@ void qb_log_from_external_source(const char *function,
 				 uint8_t priority,
 				 uint32_t lineno,
 				 uint32_t tags,
-				 ...);
+				 ...)
+	__attribute__ ((format (printf, 3, 7)));
 
 /**
  * Get or create a callsite at the give position.
@@ -323,7 +324,8 @@ void qb_log_from_external_source_va(const char *function,
 				    uint8_t priority,
 				    uint32_t lineno,
 				    uint32_t tags,
-				    va_list ap);
+				    va_list ap)
+	__attribute__ ((format (printf, 3, 0)));
 
 /**
  * This is the function to generate a log message if you want to
diff --git a/lib/log.c b/lib/log.c
index 3336af9..b6eb3ce 100644
--- a/lib/log.c
+++ b/lib/log.c
@@ -172,6 +172,12 @@ _cs_matches_filter_(struct qb_log_callsite *cs,
  * @param[in]  cs   Callsite containing format to use
  * @param[in]  ap   Variable arguments for format
  */
+#ifdef HAVE_GCC_SUGGEST_ATTRIBUTE_FORMAT
+/* suppress suggestion that we currently can do nothing better about
+   as the format specification is hidden in cs argument */
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wsuggest-attribute=format"
+#endif
 static inline void
 cs_format(char *str, struct qb_log_callsite *cs, va_list ap)
 {
@@ -188,6 +194,9 @@ cs_format(char *str, struct qb_log_callsite *cs, va_list ap)
 		str[len - 1] = '\0';
 	}
 }
+#ifdef HAVE_GCC_SUGGEST_ATTRIBUTE_FORMAT
+#pragma GCC diagnostic pop
+#endif
 
 void
 qb_log_real_va_(struct qb_log_callsite *cs, va_list ap)