diff --git a/lib/int_sqrt.c b/lib/int_sqrt.c
index db0b5aa071fc14e68fc3073e1a41c0d4617e65cf..036c96781ea85058eecbbb613460710e15107073 100644
--- a/lib/int_sqrt.c
+++ b/lib/int_sqrt.c
@@ -23,6 +23,9 @@ unsigned long int_sqrt(unsigned long x)
 		return x;
 
 	m = 1UL << (BITS_PER_LONG - 2);
+	while (m > x)
+		m >>= 2;
+
 	while (m != 0) {
 		b = y + m;
 		y >>= 1;