diff --git a/kernel/debug/kdb/kdb_io.c b/kernel/debug/kdb/kdb_io.c
index 40617f36a6db..3131334d7a81 100644
--- a/kernel/debug/kdb/kdb_io.c
+++ b/kernel/debug/kdb/kdb_io.c
@@ -239,6 +239,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
 						 * and null byte */
 	char *lastchar;
 	char *p_tmp;
+	char tmp;
 	static char tmpbuffer[CMD_BUFLEN];
 	int len = strlen(buffer);
 	int len_tmp;
@@ -246,8 +247,7 @@ static char *kdb_read(char *buffer, size_t bufsize)
 	int count;
 	int i;
 	int diag, dtab_count;
-	int key, buf_size, ret;
-
+	int key, ret;
 
 	diag = kdbgetintenv("DTABCOUNT", &dtab_count);
 	if (diag)
@@ -329,21 +329,16 @@ poll_again:
 	case 9: /* Tab */
 		if (tab < 2)
 			++tab;
-		p_tmp = buffer;
-		while (*p_tmp == ' ')
-			p_tmp++;
-		if (p_tmp > cp)
-			break;
-		memcpy(tmpbuffer, p_tmp, cp-p_tmp);
-		*(tmpbuffer + (cp-p_tmp)) = '\0';
-		p_tmp = strrchr(tmpbuffer, ' ');
-		if (p_tmp)
-			++p_tmp;
-		else
-			p_tmp = tmpbuffer;
-		len = strlen(p_tmp);
-		buf_size = sizeof(tmpbuffer) - (p_tmp - tmpbuffer);
-		count = kallsyms_symbol_complete(p_tmp, buf_size);
+
+		tmp = *cp;
+		*cp = '\0';
+		p_tmp = strrchr(buffer, ' ');
+		p_tmp = (p_tmp ? p_tmp + 1 : buffer);
+		strscpy(tmpbuffer, p_tmp, sizeof(tmpbuffer));
+		*cp = tmp;
+
+		len = strlen(tmpbuffer);
+		count = kallsyms_symbol_complete(tmpbuffer, sizeof(tmpbuffer));
 		if (tab == 2 && count > 0) {
 			kdb_printf("\n%d symbols are found.", count);
 			if (count > dtab_count) {
@@ -355,14 +350,14 @@ poll_again:
 			}
 			kdb_printf("\n");
 			for (i = 0; i < count; i++) {
-				ret = kallsyms_symbol_next(p_tmp, i, buf_size);
+				ret = kallsyms_symbol_next(tmpbuffer, i, sizeof(tmpbuffer));
 				if (WARN_ON(!ret))
 					break;
 				if (ret != -E2BIG)
-					kdb_printf("%s ", p_tmp);
+					kdb_printf("%s ", tmpbuffer);
 				else
-					kdb_printf("%s... ", p_tmp);
-				*(p_tmp + len) = '\0';
+					kdb_printf("%s... ", tmpbuffer);
+				tmpbuffer[len] = '\0';
 			}
 			if (i >= dtab_count)
 				kdb_printf("...");
@@ -373,14 +368,14 @@ poll_again:
 				kdb_position_cursor(kdb_prompt_str, buffer, cp);
 		} else if (tab != 2 && count > 0) {
 			/* How many new characters do we want from tmpbuffer? */
-			len_tmp = strlen(p_tmp) - len;
+			len_tmp = strlen(tmpbuffer) - len;
 			if (lastchar + len_tmp >= bufend)
 				len_tmp = bufend - lastchar;
 
 			if (len_tmp) {
 				/* + 1 ensures the '\0' is memmove'd */
 				memmove(cp+len_tmp, cp, (lastchar-cp) + 1);
-				memcpy(cp, p_tmp+len, len_tmp);
+				memcpy(cp, tmpbuffer+len, len_tmp);
 				kdb_printf("%s", cp);
 				cp += len_tmp;
 				lastchar += len_tmp;