Re: [PATCH 2/4] timerfd: convert to ->read_iter()

[Jens Axboe]

On 4/11/24 5:40 AM, Marek Szyprowski wrote:
> Hi,
> 
> On 11.04.2024 00:27, Jens Axboe wrote:
>> On 4/9/24 9:22 AM, Jens Axboe wrote:
>>> @@ -312,8 +313,8 @@ static ssize_t timerfd_read(struct file *file, char __user *buf, size_t count,
>>>   		ctx->ticks = 0;
>>>   	}
>>>   	spin_unlock_irq(&ctx->wqh.lock);
>>> -	if (ticks)
>>> -		res = put_user(ticks, (u64 __user *) buf) ? -EFAULT: sizeof(ticks);
>>> +	if (ticks && !copy_to_iter_full(&ticks, sizeof(ticks), to))
>>> +		res = -EFAULT;
>>>   	return res;
>>>   }
>> Dumb thinko here, as that should be:
>>
>> if (ticks) {
>> 	res = copy_to_iter(&ticks, sizeof(ticks), to);
>> 	if (!res)
>> 		res = -EFAULT;
>> }
>>
>> I've updated my branch, just a heads-up. Odd how it passing testing,
>> guess I got stack lucky...
> 
> The old version got its way into today's linux-next and bisecting the 
> boot issues directed me here. There is nothing more to report, but I can 
> confirm that the above change indeed fixes the problems observed on 
> next-20240411.

Yeah sorry about that :(

> Tested-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>

Thanks!

> I hope that tomorrow's linux-next will have the correct version of this 
> patch.

It should, the branches have been updated.

-- 
Jens Axboe