diff --git a/hw/pcnet.c b/hw/pcnet.c
index cba253ba7b..306dc6ed7e 100644
--- a/hw/pcnet.c
+++ b/hw/pcnet.c
@@ -1505,6 +1505,7 @@ static void pcnet_bcr_writew(PCNetState *s, uint32_t rap, uint32_t val)
 #ifdef PCNET_DEBUG
        printf("BCR_SWS=0x%04x\n", val);
 #endif
+        /* fall through */
     case BCR_LNKST:
     case BCR_LED1:
     case BCR_LED2:
diff --git a/json-lexer.c b/json-lexer.c
index c21338f66d..3cd3285825 100644
--- a/json-lexer.c
+++ b/json-lexer.c
@@ -301,6 +301,7 @@ static int json_lexer_feed_char(JSONLexer *lexer, char ch, bool flush)
         case JSON_KEYWORD:
         case JSON_STRING:
             lexer->emit(lexer, lexer->token, new_state, lexer->x, lexer->y);
+            /* fall through */
         case JSON_SKIP:
             QDECREF(lexer->token);
             lexer->token = qstring_new();
diff --git a/qemu-option.c b/qemu-option.c
index 6b23c31235..a303f87e1c 100644
--- a/qemu-option.c
+++ b/qemu-option.c
@@ -214,13 +214,17 @@ static int parse_option_size(const char *name, const char *value, uint64_t *ret)
         switch (*postfix) {
         case 'T':
             sizef *= 1024;
+            /* fall through */
         case 'G':
             sizef *= 1024;
+            /* fall through */
         case 'M':
             sizef *= 1024;
+            /* fall through */
         case 'K':
         case 'k':
             sizef *= 1024;
+            /* fall through */
         case 'b':
         case '\0':
             *ret = (uint64_t) sizef;