diff --git a/Makefile b/Makefile
index 08cb75e7..1442394f 100644
--- a/Makefile
+++ b/Makefile
@@ -14,7 +14,7 @@
 #
 
 PROGNAME    = afl
-VERSION     = 2.09b
+VERSION     = 2.10b
 
 PREFIX     ?= /usr/local
 BIN_PATH    = $(PREFIX)/bin
diff --git a/afl-fuzz.c b/afl-fuzz.c
index 9cd63e3e..37239dc8 100644
--- a/afl-fuzz.c
+++ b/afl-fuzz.c
@@ -7133,19 +7133,24 @@ static void get_core_count(void) {
 
 #else
 
-  /* On Linux, a simple way is to look at /proc/stat, especially since we'd
-     be parsing it anyway for other reasons later on. */
+  if (!cpu_core_count) {
 
-  FILE* f = fopen("/proc/stat", "r");
-  u8 tmp[1024];
+    /* On Linux, a simple way is to look at /proc/stat, especially since we'd
+       be parsing it anyway for other reasons later on. But do this only if
+       cpu_core_count hasn't been obtained before as a result of specifying
+       -Z. */
 
-  if (!f) return;
+    FILE* f = fopen("/proc/stat", "r");
+    u8 tmp[1024];
 
-  while (fgets(tmp, sizeof(tmp), f))
-    if (!strncmp(tmp, "cpu", 3) && isdigit(tmp[3])) cpu_core_count++;
+    if (!f) return;
+
+    while (fgets(tmp, sizeof(tmp), f))
+      if (!strncmp(tmp, "cpu", 3) && isdigit(tmp[3])) cpu_core_count++;
+
+    fclose(f);
+  }
 
-  fclose(f);
-  
 #endif /* ^(__APPLE__ || __FreeBSD__ || __OpenBSD__) */
 
   if (cpu_core_count) {
diff --git a/docs/ChangeLog b/docs/ChangeLog
index 1ff69765..45460626 100644
--- a/docs/ChangeLog
+++ b/docs/ChangeLog
@@ -16,6 +16,12 @@ Not sure if you should upgrade? The lowest currently recommended version
 is 2.07b. If you're stuck on an earlier release, it's strongly advisable
 to get on with the times.
 
+--------------
+Version 2.10b:
+--------------
+
+  - Fixed a minor core counting glitch, reported by Tyler Nighswander.
+
 --------------
 Version 2.09b:
 --------------