Re: [PATCH] ALSA: aoa: i2sbus: fix possible memory leak in i2sbus_add_dev()

[Yang Yingliang <yangyingliang@huawei.com>]

On 2022/10/27 14:38, Takashi Iwai wrote:
> On Thu, 27 Oct 2022 03:34:38 +0200,
> Yang Yingliang wrote:
>> dev_set_name() in soundbus_add_one() allocates memory for name, it need be
>> freed when of_device_register() fails, call soundbus_dev_put() to give up
>> the reference that hold in device_initialize(), so that it can be freed in
>> kobject_cleanup() when the refcount hit to 0. And other resources are also
>> freed in i2sbus_release_dev(), so it can return 0 directly.
>>
>> Fixes: f3d9478b2ce4 ("[ALSA] snd-aoa: add snd-aoa")
>> Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>
> The check of kobj state is awkward, but it seems to be the simplest
> way...  Applied now.  Thanks!

Indeed, it's awkward, shall we introduce a helper like this:

diff --git a/sound/aoa/soundbus/i2sbus/core.c 
b/sound/aoa/soundbus/i2sbus/core.c
index f6841daf9e3b..950c37e0297e 100644
--- a/sound/aoa/soundbus/i2sbus/core.c
+++ b/sound/aoa/soundbus/i2sbus/core.c
@@ -302,7 +302,7 @@ static int i2sbus_add_dev(struct macio_dev *macio,

         if (soundbus_add_one(&dev->sound)) {
                 printk(KERN_DEBUG "i2sbus: device registration error!\n");
-               if (dev->sound.ofdev.dev.kobj.state_initialized) {
+               if (soundbus_dev_initialized(&dev->sound)) {
                         soundbus_dev_put(&dev->sound);
                         return 0;
                 }
diff --git a/sound/aoa/soundbus/soundbus.h b/sound/aoa/soundbus/soundbus.h
index 3a99c1f1a3ca..2c9c95cf156a 100644
--- a/sound/aoa/soundbus/soundbus.h
+++ b/sound/aoa/soundbus/soundbus.h
@@ -174,6 +174,10 @@ struct soundbus_dev {

  extern int soundbus_add_one(struct soundbus_dev *dev);
  extern void soundbus_remove_one(struct soundbus_dev *dev);
+static inline bool soundbus_dev_initialized(struct soundbus_dev *dev)
+{
+       return dev->ofdev.dev.kobj.state_initialized;
+}


Thanks,
Yang
>
>
> Takashi
>
>
>> ---
>>   sound/aoa/soundbus/i2sbus/core.c | 4 ++++
>>   1 file changed, 4 insertions(+)
>>
>> diff --git a/sound/aoa/soundbus/i2sbus/core.c b/sound/aoa/soundbus/i2sbus/core.c
>> index faf6b03131ee..f6841daf9e3b 100644
>> --- a/sound/aoa/soundbus/i2sbus/core.c
>> +++ b/sound/aoa/soundbus/i2sbus/core.c
>> @@ -302,6 +302,10 @@ static int i2sbus_add_dev(struct macio_dev *macio,
>>   
>>   	if (soundbus_add_one(&dev->sound)) {
>>   		printk(KERN_DEBUG "i2sbus: device registration error!\n");
>> +		if (dev->sound.ofdev.dev.kobj.state_initialized) {
>> +			soundbus_dev_put(&dev->sound);
>> +			return 0;
>> +		}
>>   		goto err;
>>   	}
>>   
>> -- 
>> 2.25.1
>>
> .