Date: Mon, 12 Dec 2016 13:12:18 +0200 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 Message-ID: <20161212111218.GB54029@kib.kiev.ua> In-Reply-To: <20161211222328.GC17315@stack.nl> References: <20161201125438.15230317@mydesk.domain.cxm> <20161206104020.6b2ebb30@eto-mona.office.smartweb.sk> <20161206102637.1ddd152a@mydesk.domain.cxm> <20161207155638.4b2dd629@eto-mona.office.smartweb.sk> <630ace89-e29b-d0d3-9f15-110d8dc3de08@NTLWorld.com> <20161208132842.5d7940bd@eto-mona.office.smartweb.sk> <f5f47d55-ec8e-75b6-935d-2d0d1111c449@NTLWorld.com> <20161211124637.GA17315@stack.nl> <20161211175451.GV54029@kib.kiev.ua> <20161211222328.GC17315@stack.nl>
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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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