--- xnu/xnu-3247.10.11/iokit/Kernel/IOBufferMemoryDescriptor.cpp
+++ xnu/xnu-3248.30.4/iokit/Kernel/IOBufferMemoryDescriptor.cpp
@@ -554,6 +554,7 @@
 void IOBufferMemoryDescriptor::setLength(vm_size_t length)
 {
     assert(length <= _capacity);
+    if (length > _capacity) return;
 
     _length = length;
     _ranges.v64->length = length;