diff --git a/cgit.c b/cgit.c
index e46c00a..9305d0a 100644
--- a/cgit.c
+++ b/cgit.c
@@ -260,7 +260,7 @@ char *xstrdupn(const char *str)
 
 static void prepare_context(struct cgit_context *ctx)
 {
-	memset(ctx, 0, sizeof(ctx));
+	memset(ctx, 0, sizeof(*ctx));
 	ctx->cfg.agefile = "info/web/last-modified";
 	ctx->cfg.nocache = 0;
 	ctx->cfg.cache_size = 0;
diff --git a/ui-shared.c b/ui-shared.c
index 08ea003..8827fff 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -246,7 +246,7 @@ static void reporevlink(char *page, char *name, char *title, char *class,
 	char *delim;
 
 	delim = repolink(title, class, page, head, path);
-	if (rev && strcmp(rev, ctx.qry.head)) {
+	if (rev && ctx.qry.head != NULL && strcmp(rev, ctx.qry.head)) {
 		html(delim);
 		html("id=");
 		html_url_arg(rev);
@@ -363,7 +363,7 @@ void cgit_diff_link(char *name, char *title, char *class, char *head,
 	char *delim;
 
 	delim = repolink(title, class, "diff", head, path);
-	if (new_rev && strcmp(new_rev, ctx.qry.head)) {
+	if (new_rev && ctx.qry.head != NULL && strcmp(new_rev, ctx.qry.head)) {
 		html(delim);
 		html("id=");
 		html_url_arg(new_rev);