diff --git a/server/core/random_jkiss.c b/server/core/random_jkiss.c
index bfafd8054..feb0aa19a 100644
--- a/server/core/random_jkiss.c
+++ b/server/core/random_jkiss.c
@@ -18,6 +18,9 @@
 
 /**
  * @file random_jkiss.c  -  Random number generator for the MariaDB Corporation MaxScale
+ * 
+ * See http://www0.cs.ucl.ac.uk/staff/d.jones/GoodPracticeRNG.pdf for discussion of random
+ * number generators (RNGs).
  *
  * @verbatim
  * Revision History
@@ -35,15 +38,22 @@
 #include <unistd.h>
 #include <random_jkiss.h>
 
-/* Public domain code for JKISS RNG - Comments added */
+/* Public domain code for JKISS RNG - Comment header added */
+
+/* If possible, the seed variables will be set from /dev/urandom but
+ * should that fail, these arbitrary numbers will be used as a last resort.
+ */
 static unsigned int x = 123456789,y = 987654321,z = 43219876,c = 6543217; /* Seed variables */
 static bool init = false;
 
-static void random_init_jkiss();
+static SPINLOCK random_jkiss_spinlock = SPINLOCK_INIT;
+
+static unsigned int random_jkiss_devrand(void);
+static void random_init_jkiss(void);
 
 /***
  * 
- * Return a random number
+ * Return a pseudo-random number that satisfies major tests for random sequences
  * 
  * @return  uint    Random number
  * 
@@ -52,9 +62,13 @@ unsigned int
 random_jkiss(void)
 {
     unsigned long long t;
+    unsigned int result;
+    spinlock_acquire(&random_jkiss_spinlock);
     if (!init)
     {
+        /* Must set init first because initialisation calls this function */
         init = true;
+        spinlock_release(&random_jkiss_spinlock);
         random_init_jkiss();
     }
     x = 314527869 * x + 1234567;
@@ -64,7 +78,9 @@ random_jkiss(void)
     t = 4294584393ULL * z + c;
     c = t >> 32;
     z = t;
-    return x + y + z;
+    result = x + y + z;
+    spinlock_release(&random_jkiss_spinlock);
+    return result;
 }
 
 /* Own code adapted from http://www0.cs.ucl.ac.uk/staff/d.jones/GoodPracticeRNG.pdf */
@@ -72,19 +88,21 @@ random_jkiss(void)
 /***
  * 
  * Obtain a seed random number from /dev/urandom if available.
- * Otherwise use constant values
  * 
  * @return  uint    Random number
  * 
  */
 static unsigned int 
-random_devrand()
+random_jkiss_devrand(void)
 {
     int fn;
     unsigned int r;
-    fn = open("/dev/urandom", O_RDONLY);
-    if (fn == -1) return 0;
-    if (read(fn, &r, 4) != 4) return 0;
+    if ((fn = open("/dev/urandom", O_RDONLY)) == -1) return 0;
+    if (read(fn, &r, 4) != 4)
+    {
+        close(fn);
+        return 0;
+    }
     close(fn);
     return r;
 }
@@ -96,13 +114,15 @@ random_devrand()
  * 
  */
 static void
-random_init_jkiss()
+random_init_jkiss(void)
 {
     int newrand, i;
-    if ((newrand = random_devrand()) != 0) x = newrand;
-    if ((newrand = random_devrand()) != 0) y = newrand;
-    if ((newrand = random_devrand()) != 0) z = newrand;
-    if ((newrand = random_devrand()) != 0) 
+    if ((newrand = random_jkiss_devrand()) != 0) x = newrand;
+    if ((newrand = random_jkiss_devrand()) != 0) y = newrand;
+    if ((newrand = random_jkiss_devrand()) != 0) z = newrand;
+    if ((newrand = random_jkiss_devrand()) != 0) 
         c = newrand % 698769068 + 1; /* Should be less than 698769069 */
+    
+    /* "Warm up" our random number generator */
     for (i = 0; i < 100; i++) random_jkiss();
 }