--- a/squashfs-tools/mksquashfs.c	2019-08-06 11:03:34.071402614 -0400
+++ b/squashfs-tools/mksquashfs.c	2019-08-06 11:09:54.063340318 -0400
@@ -267,6 +267,7 @@ pthread_mutex_t	pos_mutex = PTHREAD_MUTE
 pthread_mutex_t	dup_mutex = PTHREAD_MUTEX_INITIALIZER;
 
 /* user options that control parallelisation */
+#define MAX_CPUS 256
 int processors = -1;
 int bwriter_size;
 
@@ -4124,6 +4125,10 @@ void initialise_threads(int readq, int f
 #endif
 	}
 
+	/* Limit the number of processors we're going to use */
+	if(processors > MAX_CPUS)
+		processors = MAX_CPUS;
+
 	if(multiply_overflow(processors, 3) ||
 			multiply_overflow(processors * 3, sizeof(pthread_t)))
 		BAD_ERROR("Processors too large\n");