Re: [PATCH net-next] net: add in_softirq() debug checking in napi_consume_skb()

From: Yunsheng Lin
Date: Thu Nov 19 2020 - 07:29:55 EST


On 2020/11/19 19:41, Peter Zijlstra wrote:
> On Thu, Nov 19, 2020 at 05:19:44PM +0800, Yunsheng Lin wrote:
>> On 2020/11/19 0:26, Jakub Kicinski wrote:
>>> On Wed, 18 Nov 2020 16:57:57 +0100 Peter Zijlstra wrote:
>>>> On Wed, Nov 18, 2020 at 07:43:48AM -0800, Jakub Kicinski wrote:
>>>>
>>>>> TBH the last sentence I wrote isn't clear even to me at this point ;D
>>>>>
>>>>> Maybe using just the macros from preempt.h - like this?
>>>>>
>>>>> #define lockdep_assert_in_softirq() \
>>>>> do { \
>>>>> WARN_ON_ONCE(__lockdep_enabled && \
>>>>> (!in_softirq() || in_irq() || in_nmi()) \
>>>>> } while (0)
>>
>> One thing I am not so sure about is the different irq context indicator
>> in preempt.h and lockdep.h, for example lockdep_assert_in_irq() uses
>> this_cpu_read(hardirq_context) in lockdep.h, and in_irq() uses
>> current_thread_info()->preempt_count in preempt.h, if they are the same
>> thing?
>
> Very close, for more regular code they should be the same.

Thanks for clarifying.
So I assmue the lockdep_assert_in_softirq() interface we want to add
is regular code, right?

> .
>