[PATCH v2 2/2] ioctl console test v2

[Bran S]

On Fri, 13 Mar 2020 at 23:42, Eugene Syromiatnikov <esyr at redhat.com> wrote:
>
> On Fri, Mar 13, 2020 at 04:25:03PM +0530, Bran S wrote:
> > On Wed, 11 Mar 2020 at 19:15, Eugene Syromiatnikov <esyr at redhat.com> wrote:
> > >
> > > On Wed, Mar 11, 2020 at 03:01:38PM +0530, Bran S wrote:
> > > > > Have you considered fixing strace-DDD.test?
> > > >
> > > > It is mentioned here[1] that it doesn't fail when built outside
> > > > systemd user slice.
> > >
> > > There are actually two issues: one is itermittent and is common with
> > > strace-DD.test, namingly, the waiting of the strace's termination is not
> > > done properly, so it checks the actual strace's output too early
> > > sometimes; the other one is the one you've referenced, yes.
> >
> > Will get to strace-DD.test after solving strace-DDD.test ?
> > Or are they somehow dependent and need to be solve at once ?
> >
> > > > So should we check if the ppid is of the systemd instead of checking for pid 1 ?
> > > > Would that be a solution or something else ?
> > >
> > > Why systemd?  Any process can be child subreaper for whatever reasons.
> > > Yes, it's likely that the solution is to get the subreaper's PID and
> > > check against it instead of checking against hard-coded 1.
> >
> > So if any process can be subreaper i.e. ppid can be anything greater
> > than equal to 1, then what is the point of matching the process id ?
>
> Well, matching PPID against child subreaper's PID confirms that
> the tracer is re-parented by it.

> ...

> Well, the check that PPID is no less than 0 is effectively useless,
> as it is always no less than 1.  As I said, it has to be checked
> against test's child subreaper, or at least checked that it is outside
> tracee's PID tree (however, checking it against child subreaper's PID
> is easier and makes the test more precise).

There can be any number of subreapers right ?
So Do we get list of all the available subreapers and match their PID
with our PPID ?

> > > > [1] https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=947396