Messages in this thread | | | Date | Thu, 11 Mar 2021 16:08:21 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH v3] do_wait: make PIDTYPE_PID case O(1) instead of O(n) |
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On 03/10, Eric W. Biederman wrote: > > Jim Newsome <jnewsome@torproject.org> writes: > > > +static int do_wait_pid(struct wait_opts *wo) > > +{ > > + struct task_struct *target = pid_task(wo->wo_pid, PIDTYPE_PID); > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > This is subtle change in behavior. > > Today on the task->children list we only place thread group leaders.
Aaah, yes, thanks Eric!
> So the code either needs a thread_group_leader filter on target before > the ptrace=0 case or we need to use "pid_task(wo->wo_pid, PIDTYPE_TGID)" > and "pid_task(wo->wo_pid, PIDTYPE_PID)" for the "ptrace=1" case.
Agreed,
> I would like to make thread_group_leaders go away
Hmm, why?
Oleg.
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