diff --git a/drivers/usb/mon/mon_bin.c b/drivers/usb/mon/mon_bin.c
index f6ae753ab99b..f932f40302df 100644
--- a/drivers/usb/mon/mon_bin.c
+++ b/drivers/usb/mon/mon_bin.c
@@ -1004,7 +1004,9 @@ static long mon_bin_ioctl(struct file *file, unsigned int cmd, unsigned long arg
 		break;
 
 	case MON_IOCQ_RING_SIZE:
+		mutex_lock(&rp->fetch_lock);
 		ret = rp->b_size;
+		mutex_unlock(&rp->fetch_lock);
 		break;
 
 	case MON_IOCT_RING_SIZE:
@@ -1231,12 +1233,16 @@ static int mon_bin_vma_fault(struct vm_fault *vmf)
 	unsigned long offset, chunk_idx;
 	struct page *pageptr;
 
+	mutex_lock(&rp->fetch_lock);
 	offset = vmf->pgoff << PAGE_SHIFT;
-	if (offset >= rp->b_size)
+	if (offset >= rp->b_size) {
+		mutex_unlock(&rp->fetch_lock);
 		return VM_FAULT_SIGBUS;
+	}
 	chunk_idx = offset / CHUNK_SIZE;
 	pageptr = rp->b_vec[chunk_idx].pg;
 	get_page(pageptr);
+	mutex_unlock(&rp->fetch_lock);
 	vmf->page = pageptr;
 	return 0;
 }