On Sun, Nov 11, 2018 at 06:24:37AM -0800, Greg Kroah-Hartman wrote:

The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.

This one also depends on

36156f9241cb ("of: add helper to lookup compatible child node")

Johan

------------------ original commit in Linus's tree ------------------

From 5bf59773aaf36dd62117dc83d50e1bbf9ef432da Mon Sep 17 00:00:00 2001 From: Johan Hovold johan@kernel.org Date: Mon, 27 Aug 2018 10:21:52 +0200 Subject: [PATCH] NFC: nfcmrvl_uart: fix OF child-node lookup

Use the new of_get_compatible_child() helper to lookup the nfc child node instead of using of_find_compatible_node(), which searches the entire tree from a given start node and thus can return an unrelated (i.e. non-child) node.

This also addresses a potential use-after-free (e.g. after probe deferral) as the tree-wide helper drops a reference to its first argument (i.e. the parent node).

Fixes: e097dc624f78 ("NFC: nfcmrvl: add UART driver") Fixes: d8e018c0b321 ("NFC: nfcmrvl: update device tree bindings for Marvell NFC") Cc: stable stable@vger.kernel.org # 4.2 Cc: Vincent Cuissard cuissard@marvell.com Cc: Samuel Ortiz sameo@linux.intel.com Signed-off-by: Johan Hovold johan@kernel.org Signed-off-by: Rob Herring robh@kernel.org

diff --git a/drivers/nfc/nfcmrvl/uart.c b/drivers/nfc/nfcmrvl/uart.c index 91162f8e0366..9a22056e8d9e 100644 --- a/drivers/nfc/nfcmrvl/uart.c +++ b/drivers/nfc/nfcmrvl/uart.c @@ -73,10 +73,9 @@ static int nfcmrvl_uart_parse_dt(struct device_node *node, struct device_node *matched_node; int ret;

• matched_node = of_find_compatible_node(node, NULL, "marvell,nfc-uart");

• matched_node = of_get_compatible_child(node, "marvell,nfc-uart"); if (!matched_node) {

• matched_node = of_find_compatible_node(node, NULL,
  

• 				       "mrvl,nfc-uart");
  

• matched_node = of_get_compatible_child(node, "mrvl,nfc-uart");
  

  if (!matched_node) return -ENODEV; }