diff --git a/src/time/clock_gettime.c b/src/time/clock_gettime.c
index 1572de0e..24128804 100644
--- a/src/time/clock_gettime.c
+++ b/src/time/clock_gettime.c
@@ -5,10 +5,45 @@
 #include "libc.h"
 #include "atomic.h"
 
-static int sc_clock_gettime(clockid_t clk, struct timespec *ts)
+#ifdef VDSO_CGT_SYM
+
+void *__vdsosym(const char *, const char *);
+
+static void *volatile vdso_func;
+
+static int cgt_init(clockid_t clk, struct timespec *ts)
 {
-	int r = __syscall(SYS_clock_gettime, clk, ts);
-	if (!r) return r;
+	void *p = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
+	int (*f)(clockid_t, struct timespec *) =
+		(int (*)(clockid_t, struct timespec *))p;
+	a_cas_p(&vdso_func, (void *)cgt_init, p);
+	return f ? f(clk, ts) : -ENOSYS;
+}
+
+static void *volatile vdso_func = (void *)cgt_init;
+
+#endif
+
+int __clock_gettime(clockid_t clk, struct timespec *ts)
+{
+	int r;
+
+#ifdef VDSO_CGT_SYM
+	int (*f)(clockid_t, struct timespec *) =
+		(int (*)(clockid_t, struct timespec *))vdso_func;
+	if (f) {
+		r = f(clk, ts);
+		if (!r) return r;
+		if (r == -EINVAL) return __syscall_ret(r);
+		/* Fall through on errors other than EINVAL. Some buggy
+		 * vdso implementations return ENOSYS for clocks they
+		 * can't handle, rather than making the syscall. This
+		 * also handles the case where cgt_init fails to find
+		 * a vdso function to use. */
+	}
+#endif
+
+	r = __syscall(SYS_clock_gettime, clk, ts);
 	if (r == -ENOSYS) {
 		if (clk == CLOCK_REALTIME) {
 			__syscall(SYS_gettimeofday, ts, 0);
@@ -17,25 +52,7 @@ static int sc_clock_gettime(clockid_t clk, struct timespec *ts)
 		}
 		r = -EINVAL;
 	}
-	errno = -r;
-	return -1;
-}
-
-void *__vdsosym(const char *, const char *);
-
-int __clock_gettime(clockid_t clk, struct timespec *ts)
-{
-#ifdef VDSO_CGT_SYM
-	static int (*volatile cgt)(clockid_t, struct timespec *);
-	if (!cgt) {
-		void *f = __vdsosym(VDSO_CGT_VER, VDSO_CGT_SYM);
-		if (!f) f = (void *)sc_clock_gettime;
-		a_cas_p(&cgt, 0, f);
-	}
-	return cgt(clk, ts);
-#else
-	return sc_clock_gettime(clk, ts);
-#endif
+	return __syscall_ret(r);
 }
 
 weak_alias(__clock_gettime, clock_gettime);