Re: [PATCH v2] io_uring: fix CQ waiting timeout handling

[Pavel Begunkov <asml.silence@gmail.com>]

On 1/11/23 06:39, Xiaoguang Wang wrote:
> hello,
> 
>>   	/*
>> @@ -2564,7 +2564,7 @@ static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
>>   		}
>>   		prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
>>   						TASK_INTERRUPTIBLE);
>> -		ret = io_cqring_wait_schedule(ctx, &iowq, timeout);
>> +		ret = io_cqring_wait_schedule(ctx, &iowq, &timeout);
>>   		if (__io_cqring_events_user(ctx) >= min_events)
>>   			break;
>>   		cond_resched();
> Does this bug result in any real issues?
> io_cqring_wait_schedule() calls schedule_hrtimeout(), but seems that
> schedule_hrtimeout() and its child functions don't modify timeout or expires
> at all, so I wonder how this patch works. Thanks.

Looked it up, you're right, I guess passing a pointer and one example
using it this way convinced me that it should be the case. Even more
interesting that as there is only HRTIMER_MODE_ABS and no relative
modes as before (IIRC) it wasn't a bug in the first place. Thanks
for taking a look

-- 
Pavel Begunkov