Re: [PATCH] posix-timers: Handle returned errors poperly in [i]timer_delete()

[Oleg Nesterov]

Anna-Maria, I can't really answer, I don't understand this code today ;)
That said, let me try to explain my opinion,

On 04/15, Anna-Maria Behnsen wrote:
>
> Oleg Nesterov <oleg@xxxxxxxxxx> writes:
>
> > On 04/15, Anna-Maria Behnsen wrote:
> >>
> >> timer_delete_hook() returns -EINVAL when the clock or the timer_del
> >> callback of the clock does not exist. This return value is not handled by
> >> the callsites timer_delete() and itimer_delete().
> >
> > IIUC this shouldn't happen? timer_delete_hook() WARN()s in this case,
> > not sure we need to return this error to userspace...
>
> This shouldn't happen, right.
>
> Even if we do not return this error to userspace, is it valid to proceed
> with the rest of the callsites?

Well, I'd say that nothing is safe after we hit the kernel problem.

But lets suppose we return EINVAL and skip list_del(&timer->list)/etc.
How can this help? What can userspace do to resolve this problem? Is it
better to "leak" this timer? I dunno.

> When it is fine to just ignore the
> -EINVAL return, then I would propose just to add a comment to the code.

Agreed!

Oleg.