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

Marek Szyprowski
2024-04-11T11:46:37Z

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.

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

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

Best regards
--
Marek Szyprowski, PhD
Samsung R&D Institute Poland