Re: [PATCH -tip 5/5] tracing: simplify memory recycle of trace_define_field

[Wenji Huang <wenji.huang@oracle.com>]

On 02/24/2010 04:04 PM, Li Zefan wrote:
> Wenji Huang wrote:
>> Discard freeing field->type since it's not necessary and may be hazard.
>>
>
> It's redundant, but it's safe, because if we run into this failure path,
> field->type is always NULL.

There are two entries to failure path, field->name == NULL or
field->type == NULL. And allocating for field->name is before field->type.

IMHO, field->type is not fixed after initialization, it's
not safe if field->name==NULL goes to failure path.

Regards,
Wenji
>
>> Signed-off-by: Wenji Huang<wenji.huang@oracle.com>
>
> Reviewed-by: Li Zefan<lizf@cn.fujitsu.com>
>
>> ---
>>   kernel/trace/trace_events.c |    4 +---
>>   1 files changed, 1 insertions(+), 3 deletions(-)
>>
>> diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
>> index c2a3077..3f972ad 100644
>> --- a/kernel/trace/trace_events.c
>> +++ b/kernel/trace/trace_events.c
>> @@ -60,10 +60,8 @@ int trace_define_field(struct ftrace_event_call *call, const char *type,
>>   	return 0;
>>
>>   err:
>> -	if (field) {
>> +	if (field)
>>   		kfree(field->name);
>> -		kfree(field->type);
>> -	}
>>   	kfree(field);
>>
>>   	return -ENOMEM;