[alsa-devel] [PATCH] ALSA: seq: initialize whole fields of automatic variable with union type

[Takashi Sakamoto]

On Aug 30 2016 14:11, Takashi Iwai wrote:
> On Tue, 30 Aug 2016 02:11:54 +0200,
> Takashi Sakamoto wrote:
>>
>> Currently, automatic variable of 'union ioctl_arg' type is initialized
>> by designated initialization. Although, the actual effect is interpretation
>> of early element of int type and initialization of 'int pversion'.
>> Therefore the first field corresponding to int type is initialized to zero.
>> This is against my expectation to initialize whole fields.
>>
>> This commit uses memset() to initialize the variable, instead of designated
>> initialization.
>>
>> Fixes: 04a56dd8ed0d ('ALSA: seq: change ioctl command operation to get data in kernel space')
>> Signed-off-by: Takashi Sakamoto <o-takashi at sakamocchi.jp>
>> ---
>>  sound/core/seq/seq_clientmgr.c | 5 ++++-
>>  1 file changed, 4 insertions(+), 1 deletion(-)
>>
>> diff --git a/sound/core/seq/seq_clientmgr.c b/sound/core/seq/seq_clientmgr.c
>> index 286394b..fd50c38 100644
>> --- a/sound/core/seq/seq_clientmgr.c
>> +++ b/sound/core/seq/seq_clientmgr.c
>> @@ -2100,7 +2100,7 @@ static long snd_seq_ioctl(struct file *file, unsigned int cmd,
>>  		struct snd_seq_client_pool	client_pool;
>>  		struct snd_seq_remove_events	remove_events;
>>  		struct snd_seq_query_subs	query_subs;
>> -	} buf = {0};
>> +	} buf;
>>  	const struct ioctl_handler *handler;
>>  	unsigned long size;
>>  	int err;
>> @@ -2114,6 +2114,9 @@ static long snd_seq_ioctl(struct file *file, unsigned int cmd,
>>  	}
>>  	if (handler->cmd == 0)
>>  		return -ENOTTY;
>> +
>> +	memset(&buf, 0, sizeof(union ioctl_arg));
>
> The common practice is to pass sizeof(buf).

OK. I'll post revised version later.


Regards

Takashi Sakamoto