Re: [PATCH 4.14 58/62] mtd: rawnand: atmel: fix OF child-node lookup

Sasha Levin
2018-11-26T15:16:08Z

On Mon, Nov 26, 2018 at 04:08:40PM +0100, Boris Brezillon wrote:
>On Mon, 26 Nov 2018 19:46:15 +0530
>Naresh Kamboju <naresh.kamboju@linaro.org> wrote:
>
>> Do you see build failure arm x15 beagleboard on 4.14 due to this patch ?
>>
>> On Mon, 26 Nov 2018 at 16:31, Greg Kroah-Hartman
>> <gregkh@linuxfoundation.org> wrote:
>> >
>> > 4.14-stable review patch. If anyone has any objections, please let me know.
>> >
>> > ------------------
>> >
>> > From: Johan Hovold <johan@kernel.org>
>> >
>> > commit 5d1e9c2212ea6b4dd735e4fc3dd6279a365d5d10 upstream.
>> >
>> > 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 node of the device being probed).
>> >
>> > While at it, also fix a related nfc-node reference leak.
>> >
>> > Fixes: f88fc122cc34 ("mtd: nand: Cleanup/rework the atmel_nand driver")
>> > Cc: stable <stable@vger.kernel.org> # 4.11
>> > Cc: Nicolas Ferre <nicolas.ferre@microchip.com>
>> > Cc: Josh Wu <rainyfeeling@outlook.com>
>> > Cc: Boris Brezillon <boris.brezillon@bootlin.com>
>> > Signed-off-by: Johan Hovold <johan@kernel.org>
>> > Signed-off-by: Boris Brezillon <boris.brezillon@bootlin.com>
>> > Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
>> >
>> > ---
>> > drivers/mtd/nand/atmel/nand-controller.c | 11 +++++++----
>> > 1 file changed, 7 insertions(+), 4 deletions(-)
>> >
>> > --- a/drivers/mtd/nand/atmel/nand-controller.c
>> > +++ b/drivers/mtd/nand/atmel/nand-controller.c
>> > @@ -2077,8 +2077,7 @@ atmel_hsmc_nand_controller_legacy_init(s
>> > int ret;
>> >
>> > nand_np = dev->of_node;
>> > - nfc_np = of_find_compatible_node(dev->of_node, NULL,
>> > - "atmel,sama5d3-nfc");
>> > + nfc_np = of_get_compatible_child(dev->of_node, "atmel,sama5d3-nfc");
>> > if (!nfc_np) {
>> > dev_err(dev, "Could not find device node for sama5d3-nfc\n");
>> > return -ENODEV;
>> > @@ -2492,15 +2491,19 @@ static int atmel_nand_controller_probe(s
>> > }
>> >
>> > if (caps->legacy_of_bindings) {
>> > + struct device_node *nfc_node;
>> > u32 ale_offs = 21;
>> >
>> > /*
>> > * If we are parsing legacy DT props and the DT contains a
>> > * valid NFC node, forward the request to the sama5 logic.
>> > */
>> > - if (of_find_compatible_node(pdev->dev.of_node, NULL,
>> > - "atmel,sama5d3-nfc"))
>> > + nfc_node = of_get_compatible_child(pdev->dev.of_node,
>> > + "atmel,sama5d3-nfc");
>> > + if (nfc_node) {
>> > caps = &atmel_sama5_nand_caps;
>> > + of_node_put(nfc_node);
>> > + }
>> >
>> > /*
>> > * Even if the compatible says we are dealing with an
>> >
>> >
>>
>> /drivers/mtd/nand/atmel/nand-controller.c: In function
>> 'atmel_hsmc_nand_controller_legacy_init':
>> /drivers/mtd/nand/atmel/nand-controller.c:2080:11: error: implicit
>> declaration of function 'of_get_compatible_child'; did you mean
>> 'of_get_next_available_child'? [-Werror=implicit-function-declaration]
>> nfc_np = of_get_compatible_child(dev->of_node, "atmel,sama5d3-nfc");
>
>Looks like of_get_compatible_child() has been introduced in 4.18, hence
>this error.
>
>Greg, can you drop this patch from 4.14.y?

Interesting, none of the kernelci builds caught this? hmm

--
Thanks,
Sasha