On 2013/3/15 9:26, li guang wrote:
> 在 2013-03-15五的 09:01 +0800，Li Zefan写道：
>> On 2013/3/15 8:20, li guang wrote:
>>> 在 2013-03-14四的 15:43 +0100，Oleg Nesterov写道：
>>>> On 03/14, liguang wrote:
>>>>>
>>>>> Signed-off-by: liguang <lig.f...@cn.fujitsu.com>
>>>>> ---
>>>>> kernel/task_work.c | 3 ++-
>>>>> 1 files changed, 2 insertions(+), 1 deletions(-)
>>>>>
>>>>> diff --git a/kernel/task_work.c b/kernel/task_work.c
>>>>> index 0bf4258..f458b08 100644
>>>>> --- a/kernel/task_work.c
>>>>> +++ b/kernel/task_work.c
>>>>> @@ -75,7 +75,8 @@ void task_work_run(void)
>>>>>
>>>>> do {
>>>>> next = work->next;
>>>>> - work->func(work);
>>>>> + if (unlikely(work->func))
>>>>> + work->func(work);
>>>>
>>>> Why?
>>>>
>>>> Oleg.
>>>>
>>>
>>> can we believe a callback always be call-able?
>>> can it happened to be 0? e.g. wrong initialized.
>>> of course, we can complain the caller, be why don't
>>> we easily make it more safer?
>>>
>>
>> Because you're not making things safer, but your're trying
>> to cover up bugs...
>>
>
> Oh, that's a little harsh to a normal programmer like me :-)
> for it seems you are asking me to be coding without any bug.
> are you? or it is the theory of kernel coding?
>
And you make a bug, and you want the kernel to cover up the bug
instead of crash on a null pointer deref so you'll know you've
made a bug?
Why we check if a callback is NULL before calling it? Because
it's allowed to be. Why we don't check if a callback is NULL?
Because it's not supposed to be.
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
