diff --git a/src/cfgparse.c b/src/cfgparse.c
index 5c292f82d..40a21e784 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -2288,9 +2288,9 @@ int check_config_validity()
 			/* detect and address thread affinity inconsistencies */
 			nbproc = 0;
 			if (bind_conf->bind_proc)
-				nbproc = my_ffsl(bind_conf->bind_proc);
+				nbproc = my_ffsl(bind_conf->bind_proc) - 1;
 
-			mask = bind_conf->bind_thread[nbproc - 1];
+			mask = bind_conf->bind_thread[nbproc];
 			if (mask && !(mask & all_threads_mask)) {
 				unsigned long new_mask = 0;