diff --git a/drivers/mmc/core/debugfs.c b/drivers/mmc/core/debugfs.c
index c8451ce..30623b8 100644
--- a/drivers/mmc/core/debugfs.c
+++ b/drivers/mmc/core/debugfs.c
@@ -321,7 +321,11 @@ static int mmc_ext_csd_open(struct inode *inode, struct file *filp)
 	for (i = 0; i < 512; i++)
 		n += sprintf(buf + n, "%02x", ext_csd[i]);
 	n += sprintf(buf + n, "\n");
-	BUG_ON(n != EXT_CSD_STR_LEN);
+
+	if (n != EXT_CSD_STR_LEN) {
+		err = -EINVAL;
+		goto out_free;
+	}
 
 	filp->private_data = buf;
 	kfree(ext_csd);