Re: [PATCH v4 0/2] fix & prevent the missing preemption disabling

[王贇]

On 2021/10/26 上午10:42, Steven Rostedt wrote:
> On Tue, 26 Oct 2021 10:09:12 +0800
> 王贇 <yun.wang@xxxxxxxxxxxxxxxxx> wrote:
> 
>> Just a ping, to see if there are any more comments :-P
> 
> I guess you missed what went into mainline (and your name found a bug
> in my perl script for importing patches ;-)
> 
>   https://lore.kernel.org/all/20211019091344.65629198@xxxxxxxxxxxxxxxxxx/

Cool~ Missing some chinese font maybe, that's fine :-)

> 
> Which means patch 1 needs to change:
>> +	/*
>> +	 * Disable preemption to fulfill the promise.
>> +	 *
>> +	 * Don't worry about the bit 0 cases, they indicate
>> +	 * the disabling behaviour has already been done by
>> +	 * internal call previously.
>> +	 */
>> +	preempt_disable_notrace();
>> +
>>  	return bit + 1;
>>  }
>>
>> +/*
>> + * Preemption will be enabled (if it was previously enabled).
>> + */
>>  static __always_inline void trace_clear_recursion(int bit)
>>  {
>>  	if (!bit)
>>  		return;
>>
>> +	if (bit > 0)
>> +		preempt_enable_notrace();
>> +
> 
> Where this wont work anymore.
> 
> Need to preempt disable and enable always.

Yup, will rebase on the latest changes~

Regards,
Michael Wang

> 
> -- Steve
> 
> 
>>  	barrier();
>>  	bit--;
>>  	trace_recursion_clear(bit);
>> @@ -209,7 +227,7 @@ static __always_inline void trace_clear_recursion(int bit)
>>   * tracing recursed in the same context (normal vs interrupt),
>>   *