diff --git a/ui-shared.c b/ui-shared.c
index 3e9282f..d7d75bf 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -294,7 +294,7 @@ void cgit_log_link(const char *name, const char *title, const char *class,
 	char *delim;
 
 	delim = repolink(title, class, "log", head, path);
-	if (rev && strcmp(rev, ctx.qry.head)) {
+	if (rev && ctx.qry.head && strcmp(rev, ctx.qry.head)) {
 		html(delim);
 		html("id=");
 		html_url_arg(rev);
@@ -338,7 +338,7 @@ void cgit_commit_link(char *name, const char *title, const char *class,
 	char *delim;
 
 	delim = repolink(title, class, "commit", head, path);
-	if (rev && strcmp(rev, ctx.qry.head)) {
+	if (rev && ctx.qry.head && strcmp(rev, ctx.qry.head)) {
 		html(delim);
 		html("id=");
 		html_url_arg(rev);
diff --git a/ui-ssdiff.c b/ui-ssdiff.c
index 9fb5b11..0cff4b8 100644
--- a/ui-ssdiff.c
+++ b/ui-ssdiff.c
@@ -23,7 +23,7 @@ static void create_or_reset_lcs_table()
 	int i;
 
 	if (L != NULL) {
-		memset(*L, 0, sizeof(*L) * MAX_SSDIFF_SIZE);
+		memset(*L, 0, sizeof(int) * MAX_SSDIFF_SIZE);
 		return;
 	}
 
@@ -42,14 +42,12 @@ static char *longest_common_subsequence(char *A, char *B)
 	int i, j, ri;
 	int m = strlen(A);
 	int n = strlen(B);
-	int tmp1, tmp2, length;
+	int tmp1, tmp2;
 	int lcs_length;
 	char *result;
 
-	length = (m + 1) * (n + 1);
-
 	// We bail if the lines are too long
-	if (length > MAX_SSDIFF_SIZE)
+	if (m >= MAX_SSDIFF_M || n >= MAX_SSDIFF_N)
 		return NULL;
 
 	create_or_reset_lcs_table();