[PATCH 7/9] ptrace: Simplify the wait_task_inactive call in ptrace_check_attach

[Oleg Nesterov]

On 04/28, Peter Zijlstra wrote:
>
> On Thu, Apr 28, 2022 at 01:19:11PM +0200, Oleg Nesterov wrote:
> > > That is also the reason I couldn't do wait_task_inactive(task, 0)
> >
> > Ah, I din't notice this patch uses wait_task_inactive(child, 0),
> > I think it should do wait_task_inactive(child, __TASK_TRACED).
>
> Shouldn't we then switch wait_task_inactive() so have & matching instead
> of the current ==.

Sorry, I don't understand the context...

As long as ptrace_freeze_traced() sets __state == __TASK_TRACED (as it
currently does) wait_task_inactive(__TASK_TRACED) is what we need ?

After we change it to use JOBCTL_DELAY_WAKEKILL and not abuse __state,
ptrace_attach() should use wait_task_inactive(TASK_TRACED), but this
depends on what exactly we are going to do...

Oleg.