Re: [patch 14/45] posix-timers: Consolidate interval retrieval

[Thomas Gleixner]

On Fri, Jun 30 2023 at 16:04, Frederic Weisbecker wrote:
> On Fri, Jun 30, 2023 at 03:07:17PM +0200, Thomas Gleixner wrote:
>> How exactly does this end up being copied to user space if ret != 0?
>
> kc->timer_get() doesn't return any value.
>
> So before the patch, interval is retrieved only if the target is not reaped:
>
> timer_gettime() {
>     do_timer_gettime() {
>         posix_cpu_timer_get() {
>             p = cpu_timer_task_rcu(timer);
>             if (p)
>                 itp->interval = ....
>         }
>     }
> }
>
> After the patch it's retrieved unconditionally:
>
> timer_gettime() {
>     do_timer_gettime() {
>         //unconditionally set
>         itp->interval = ....
>         posix_cpu_timer_get() {
>             p = cpu_timer_task_rcu(timer);
>             if (!p)
>                 //doesn't return any value so no failure reported

Duh. you are right ...