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SubjectRe: [PATCH] input: mtk-pmic-keys: Fix probe when no DT node present
On Fri, Jun 22, 2018 at 01:42:28PM +0200, Matthias Brugger wrote:
> The drivers gets probed from a mfd devices. So the driver runs
> probe although no DT node exists. This leads to a NULL pointer
> dereference in the probe function. Check if a node exists and
> error out in case none is present.

Hmm, if a cell specifies of_compatible and no such node is present in DT
maybe we should bail out in mfd_add_device() instead of pushing the
check into individual drivers? Something like:

diff --git a/drivers/mfd/mfd-core.c b/drivers/mfd/mfd-core.c
index 94e3f32ce935..36a5fd98000d 100644
--- a/drivers/mfd/mfd-core.c
+++ b/drivers/mfd/mfd-core.c
@@ -137,6 +137,18 @@ static inline void mfd_acpi_add_device(const struct mfd_cell *cell,
}
#endif

+static struct device_node *mfd_get_node_for_cell(struct device *parent,
+ const struct mfd_cell *cell)
+{
+ struct device_node *np;
+
+ for_each_child_of_node(parent->of_node, np)
+ if (of_device_is_compatible(np, cell->of_compatible))
+ return np;
+
+ return NULL;
+}
+
static int mfd_add_device(struct device *parent, int id,
const struct mfd_cell *cell, atomic_t *usage_count,
struct resource *mem_base,
@@ -144,7 +156,6 @@ static int mfd_add_device(struct device *parent, int id,
{
struct resource *res;
struct platform_device *pdev;
- struct device_node *np = NULL;
int ret = -ENOMEM;
int platform_id;
int r;
@@ -176,11 +187,11 @@ static int mfd_add_device(struct device *parent, int id,
goto fail_res;

if (parent->of_node && cell->of_compatible) {
- for_each_child_of_node(parent->of_node, np) {
- if (of_device_is_compatible(np, cell->of_compatible)) {
- pdev->dev.of_node = np;
- break;
- }
+ pdev->dev.of_node = mfd_get_node_for_cell(parent, cell);
+ if (!pdev->dev.of_node) {
+ dev_err(parent, "unable to locate node for %s (%s)\n",
+ cell->name, cell->of_compatible);
+ goto fail_res;
}
}

Lee?
>
> Fixes: 3e9f0b3e2b27 ("input: Add MediaTek PMIC keys support")
> Signed-off-by: Matthias Brugger <mbrugger@suse.com>
> ---
> drivers/input/keyboard/mtk-pmic-keys.c | 3 +++
> 1 file changed, 3 insertions(+)
>
> diff --git a/drivers/input/keyboard/mtk-pmic-keys.c b/drivers/input/keyboard/mtk-pmic-keys.c
> index 02c67a1749fc..388043e1939c 100644
> --- a/drivers/input/keyboard/mtk-pmic-keys.c
> +++ b/drivers/input/keyboard/mtk-pmic-keys.c
> @@ -257,6 +257,9 @@ static int mtk_pmic_keys_probe(struct platform_device *pdev)
> const struct of_device_id *of_id =
> of_match_device(of_mtk_pmic_keys_match_tbl, &pdev->dev);
>
> + if (of_id == NULL)
> + return -ENODEV;
> +
> keys = devm_kzalloc(&pdev->dev, sizeof(*keys), GFP_KERNEL);
> if (!keys)
> return -ENOMEM;
> --
> 2.17.1
>

Thanks.

--
Dmitry

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