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SubjectRe: [PATCH] leds: fix a potential NULL pointer dereference
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Hi Geert,

Thank you for the notification.

On 3/31/19 11:06 AM, Geert Uytterhoeven wrote:
> Hi Jacek,
>
> On Sun, Mar 10, 2019 at 9:40 PM Jacek Anaszewski
> <jacek.anaszewski@gmail.com> wrote:
>> On 3/9/19 7:04 AM, Kangjie Lu wrote:
>>> In case of_match_device cannot find a match, the fixes returns
>>> -EINVAL to avoid NULL pointer dereference.
>>>
>>> Signed-off-by: Kangjie Lu <kjlu@umn.edu>
>>> ---
>>> drivers/leds/leds-pca9532.c | 8 ++++++--
>>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/leds/leds-pca9532.c b/drivers/leds/leds-pca9532.c
>>> index 7fea18b0c15d..4b0335591728 100644
>>> --- a/drivers/leds/leds-pca9532.c
>>> +++ b/drivers/leds/leds-pca9532.c
>>> @@ -513,6 +513,7 @@ static int pca9532_probe(struct i2c_client *client,
>>> const struct i2c_device_id *id)
>>> {
>>> int devid;
>>> + const struct of_device_id *of_id;
>>> struct pca9532_data *data = i2c_get_clientdata(client);
>>> struct pca9532_platform_data *pca9532_pdata =
>>> dev_get_platdata(&client->dev);
>>> @@ -528,8 +529,11 @@ static int pca9532_probe(struct i2c_client *client,
>>> dev_err(&client->dev, "no platform data\n");
>>> return -EINVAL;
>>> }
>>> - devid = (int)(uintptr_t)of_match_device(
>>> - of_pca9532_leds_match, &client->dev)->data;
>>> + of_id = of_match_device(of_pca9532_leds_match,
>>> + &client->dev);
>>> + if (unlikely(!of_id))
>
> Use of unlikey() is frowned upon.

What do you mean? Can you give some reference?

> Moreover, this cannot happen, as pca9532_of_populate_pdata() already
> contains a similar check.

Right, I assumed this fixes a real problem and didn't spent too much
time investigating the whole context.. Lesson for the future.

> Kangjie: please stop submitting patches for missing checks, without
> investigating if the failures can actually happen. Thanks!
>
>>> + return -EINVAL;
>>> + devid = (int)of_id->data;
>>> } else {
>>> devid = id->driver_data;
>>> }
>>
>>
>> Applied to the for-5.2 branch of linux-leds.git.
>
> And also as a fix for v5.1...

Yes, but it had been in linux-next for almost two weeks before that.

--
Best regards,
Jacek Anaszewski

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