From: Konstantin Belousov <kostikbel@gmail.com>
To: Jilles Tjoelker <jilles@stack.nl>
Cc: FreeBSD Hackers <freebsd-hackers@freebsd.org>,
Jonathan de Boyne Pollard
<J.deBoynePollard-newsgroups@NTLWorld.com>,
supervision@list.skarnet.org
Subject: Re: NOTE_TRACK, EVFILT_PROC, kqueue, and subreapers
Date: Mon, 12 Dec 2016 13:12:18 +0200 [thread overview]
Message-ID: <20161212111218.GB54029@kib.kiev.ua> (raw)
In-Reply-To: <20161211222328.GC17315@stack.nl>
On Sun, Dec 11, 2016 at 11:23:28PM +0100, Jilles Tjoelker wrote:
> On Sun, Dec 11, 2016 at 07:54:51PM +0200, Konstantin Belousov wrote:
> > On Sun, Dec 11, 2016 at 01:46:38PM +0100, Jilles Tjoelker wrote:
> > > As reported in https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=213928
> > > reapers do not receive SIGCHLD when inheriting zombies, although they do
> > > receive SIGCHLD when an inherited descendant process later terminates
> > > and are awakened when in a wait call for a matching process. This should
> > > probably be fixed.
> > I agree, in principle. Could you update your tests/sys/kern/reaper.c to
> > include this scenario ?
>
> I tested with the patch below. The new test case
> reaper_sigchld_child_first already passes and I have marked
> reaper_sigchld_grandchild_first as an expected timeout.
>
> > Untested change to the kernel side is below.
>
> > diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
> > index f4f453c3556..92899740eef 100644
> > --- a/sys/kern/kern_exit.c
> > +++ b/sys/kern/kern_exit.c
> > @@ -455,6 +455,12 @@ exit1(struct thread *td, int rval, int signo)
> >
> > if (!(q->p_flag & P_TRACED)) {
> > proc_reparent(q, q->p_reaper);
> > + if (q->p_state == PRS_ZOMBIE) {
> > + PROC_LOCK(q->p_reaper);
> > + pksignal(q->p_reaper, SIGCHLD, q->p_ksi);
> > + wakeup(q->p_reaper);
> > + PROC_UNLOCK(q->p_reaper);
> > + }
> > } else {
> > /*
> > * Traced processes are killed since their existence
>
> This change makes reaper_sigchld_grandchild_first pass.
>
> The wakeup added here is redundant with the one a few lines above:
> if (q != NULL) /* only need this if any child is S_ZOMB */
> wakeup(q->p_reaper);
I removed additional wakeup, it should be innocent. Might be the better
change is to remove the lines you cited above and do wakeups inside the
loop after reparenting. But I kept it that way for now.
>
> This is also clear because reaper_wait_grandchild_first already passes.
>
> Index: tests/sys/kern/reaper.c
Thank you, I verified that all tests pass with the patched kernel and
removed timeouts from your reaper_sigchld_*child_first new tests.
The kernel chunk is committed as r309886, please commit tests.
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next prev parent reply other threads:[~2016-12-12 11:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20161102185444.GA911@protected.rcdrun.com>
[not found] ` <20161201081829.GG1487@protected.rcdrun.com>
[not found] ` <20161201120531.374588b2@mydesk.domain.cxm>
[not found] ` <20161201172846.GP3428@protected.rcdrun.com>
[not found] ` <20161201124118.46778e2b@mydesk.domain.cxm>
[not found] ` <20161201174837.GR3428@protected.rcdrun.com>
[not found] ` <20161201125438.15230317@mydesk.domain.cxm>
[not found] ` <20161206104020.6b2ebb30@eto-mona.office.smartweb.sk>
[not found] ` <20161206102637.1ddd152a@mydesk.domain.cxm>
[not found] ` <20161207155638.4b2dd629@eto-mona.office.smartweb.sk>
[not found] ` <630ace89-e29b-d0d3-9f15-110d8dc3de08@NTLWorld.com>
[not found] ` <20161208132842.5d7940bd@eto-mona.office.smartweb.sk>
2016-12-08 20:23 ` Jonathan de Boyne Pollard
2016-12-11 12:46 ` Jilles Tjoelker
2016-12-11 17:54 ` Konstantin Belousov
2016-12-11 22:23 ` Jilles Tjoelker
2016-12-12 11:12 ` Konstantin Belousov [this message]
2016-12-13 12:39 ` Jonathan de Boyne Pollard
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