Re: [PATCH 2/5] sched,ptrace: Fix ptrace_check_attach() vs PREEMPT_RT

From: Peter Zijlstra
Date: Fri Apr 15 2022 - 08:02:09 EST


On Fri, Apr 15, 2022 at 12:57:56PM +0200, Oleg Nesterov wrote:
> On 04/15, Oleg Nesterov wrote:
> >
> > OK, so far it seems that this patch needs a couple of simple fixes you
> > pointed out, but before I send V2:
> >
> > - do you agree we can avoid JOBCTL_TRACED_FROZEN in 1-2 ?
> >
> > - will you agree if I change ptrace_freeze_traced() to rely
> > on __state == TASK_TRACED rather than task_is_traced() ?
> >
>
> Forgot to say, I think 1/5 needs some changes in any case...
>
> ptrace_resume() does wake_up_state(child, __TASK_TRACED) but doesn't
> clear JOBCTL_TRACED. The "else" branch in ptrace_stop() leaks this flag
> too.

Urgh, yes, I seemed to have missed that one :-(