X-Recipient: archive-cygwin AT delorie DOT com
DomainKey-Signature: a=rsa-sha1; c=nofws; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; q=dns; s=
	default; b=Z4KV/BL2i3SHHnMOwC/qyl3HF/T5d11K1N7LYIwx9IAALAUSvFsJ7
	IDDRQNthMIrVOaunM3r8/J3lUHs8+2Kib2wUv8uRF5TPowcfhFc14nKDx5bCWzDI
	eyIP0TFDgvquwUcxHRDbAGZleTQxw4inDWOQ7qBm102SR83qTsyrq4=
DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=sourceware.org; h=list-id
	:list-unsubscribe:list-subscribe:list-archive:list-post
	:list-help:sender:date:from:to:subject:message-id:reply-to
	:references:mime-version:content-type:in-reply-to; s=default;
	 bh=jWKREid+HS/vniUqcs/HrrCgo/c=; b=jzkEe4v3w4twyKk9Ue0lMapCwgRR
	P5SDVOhBLLOVSSvBQ6B6kpHAwg8X9OCDGbw2zfAJOdSwyEWawya2BgZsWyKr7Mbt
	MdFa9TFZz25RiCP0QxtoJz5e3Oe0J2uyecCqSE0bX8604QZQprga3BYoSP58R8iT
	WJmr6MK5nMUkmeM=
Mailing-List: contact cygwin-help AT cygwin DOT com; run by ezmlm
List-Id: <cygwin.cygwin.com>
List-Subscribe: <mailto:cygwin-subscribe AT cygwin DOT com>
List-Archive: <http://sourceware.org/ml/cygwin/>
List-Post: <mailto:cygwin AT cygwin DOT com>
List-Help: <mailto:cygwin-help AT cygwin DOT com>, <http://sourceware.org/ml/#faqs>
Sender: cygwin-owner AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
Delivered-To: mailing list cygwin AT cygwin DOT com
Authentication-Results: sourceware.org; auth=none
X-Virus-Found: No
X-Spam-SWARE-Status: No, score=-98.4 required=5.0 tests=AWL,BAYES_50,GOOD_FROM_CORINNA_CYGWIN,KAM_LAZY_DOMAIN_SECURITY,RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.2 spammy=inglis, Inglis, Brian, brian
X-HELO: mout.kundenserver.de
Date: Sun, 25 Mar 2018 12:24:22 +0200
From: Corinna Vinschen <corinna-cygwin AT cygwin DOT com>
To: cygwin AT cygwin DOT com
Subject: Re: Odd hang in python waiting for child; strace wakes hung process?
Message-ID: <20180325102422.GC14026@calimero.vinschen.de>
Reply-To: cygwin AT cygwin DOT com
Mail-Followup-To: cygwin AT cygwin DOT com
References: <CAPF-yOYzTr-jh__S_imaAcdk5Vf4tGD1xFLuTDu4-qsg_+HiCA AT mail DOT gmail DOT com> <877eq5fedf DOT fsf AT Rainer DOT invalid> <CAPF-yOb8O+Xhp3yi9wGFFJDvrSA0W24LZ+1adAcga--H7=qaZw AT mail DOT gmail DOT com> <f41916ed-6b32-8459-d9ca-d7064e49c4be AT SystematicSw DOT ab DOT ca> <20180322165908 DOT GI6761 AT calimero DOT vinschen DOT de> <e2a3067b-586e-a334-e316-a4f54c99f082 AT SystematicSw DOT ab DOT ca>
MIME-Version: 1.0
Content-Type: multipart/signed; micalg=pgp-sha256;	protocol="application/pgp-signature"; boundary="3siQDZowHQqNOShm"
Content-Disposition: inline
In-Reply-To: <e2a3067b-586e-a334-e316-a4f54c99f082@SystematicSw.ab.ca>
User-Agent: Mutt/1.9.2 (2017-12-15)
X-UI-Out-Filterresults: notjunk:1;V01:K0:gq3iJR8jhRE=:fjKQ+Cg5PSe2Im9hdtmcDD IkpN3qR/EYCwfLHgNzVC0/O3K1WT4ega2DmJUl8MzcE7pRhafPJhwguddu7AGUDEM9IUic8R4 bETw7t7NTwJZTy5G1bjgz0zNCi7j8Aqdg84Uf9jJKsq8Q8oCn1EHJrhaXgLxtxxc0qgnWoQiI D8D6+aroipbrkZ+4XvwOLDLDNg0eNW6/xDtEytIRInFSXraK1vkOW1awrIyieHeANAy6CPdeC DDByGK1vfanm3IDPrji2JXECoGO0T4H7BJ/vGddEHqTOJPSx2wAypgkOXkbarWSaW4kqlzQZK rjKleoiFLN8Jt/c4IEg11C2Dxr8zgVf+a4l2sVc65Rdiq9ECCY/wcIMZthtf5L8eFjdFcHsOF uYRYfNPw/f+3ClV0D22gcG8P62GCR6/3cVoNQjSWUr0IErrVEhbJkkavLs8KA/JtlJVUaJixi wkY7wsjs9/LTwquuLOY0XMHadnXErFi/F8MsqeAUojZOwO030GAzjh2ye0SGvTXj0Qr9InZ+l GH9upz9LHiDVyfx2qllGBnCOzYiTGw2zJ7+/x0Slz9naTbna+OjyTx2TohAcSvHXmCwCBoMdP AeCGGOI0BzpMlGvvwOP6HJuS1Edrqltffg0d+A4V99Z7hOzGYypyBo+5WXJ2rJcJhjSqfqMH9 cEcHsMfaGFAjEivG0shJk95yPaagczORalQNwYgf0Xg9BahsK7YoxCytlYcPqfJERGPzbWtSe Y4GTIhfqAFeCsjXUsEYULvOlXmTQ4VG7mKGLKA==

--3siQDZowHQqNOShm
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: quoted-printable

On Mar 23 19:21, Brian Inglis wrote:
> On 2018-03-22 10:59, Corinna Vinschen wrote:
> > On Mar 21 23:41, Brian Inglis wrote:
> >> On 2018-03-21 16:07, Dan Kegel wrote:
> >>> On Wed, Mar 21, 2018 at 11:54 AM, Achim Gratz <Stromeko AT nexgo DOT de> wro=
te:
> >>>> Well, with the sporadic hanging/defunct processes at work my routine=
 is
> >>>> to send CONT to all Cygwin processes, then HUP/KILL to anything that=
's
> >>>> still not live or gone and then another round of CONT.  This works
> >>>> _most_ of the time, anything more stubborn I /bin/kill -f usually.
> >>>
> >>> Since I wrote, both bots hung again.  This time I verified:
> >>> 0) both had the defunct git process as expected
> >>> 1) kill -CONT the-pid doesn't do anything, nor does kill -9.  It's tr=
uly wedged.
> >>> 2) the process stays in its spin hang until you ^C strace -p the-pid
> >>> 3) ^C-ing the strace causes the process to terminate (strace alone do=
esn't)
> >>> 4) taskkill /pid the-task /f also kills the process successfully.
> >>>
> >>> So I could write a script that watched for defunct git processes
> >>> and taskkilled their parent.  Build jobs would fail, but at least
> >>> the bot would stay up.  Of course it would be much nicer if
> >>> the cygwin python process didn't get wedged.
> >>>
> >>> Alternately, I suppose I could try running native python...
> >>> or cygwin's python3... but dangit, kill -9 should work.
> >>
> >> Seems to be looping on access failure to a Windows mailslot; not sure =
what this
> >> feature is normally used for: dmesg/syslog messages/AF_UNIX sockets?
> >=20
> > /dev/kmsg is implemented using a mailslot under the hood.  This
> > feature is only used to log exceptions and for nothing else since
> > nobody ever found another reason to use it for.
> >=20
> > It would be interesting to learn if the perl hangs have the same reason.
> >=20
> > I guess we can simply remove /dev/kmsg support completely and drop
> > the mailslot code.  I'm pretty sure nobody would miss it.  Hardly
> > anybody knows it exists...
>=20
> Is /dev/log implemented the same way?

No.  /dev/log is a AF_UNIX socket.

> Looks like syslog-ng stopped working around the last upgrade:
>=20
> $ cat /var/log/syslog-ng.log
> Error reading serialized data; error=3D'Error reading file (short read)'
> Persistent configuration file is in invalid format, ignoring;
> Error binding socket; addr=3D'AF_UNIX(/dev/log)', error=3D'Address alread=
y in use (112)'

rm -rf /dev/log


Corinna

--=20
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat

--3siQDZowHQqNOShm
Content-Type: application/pgp-signature; name="signature.asc"

-----BEGIN PGP SIGNATURE-----
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=7wRw
-----END PGP SIGNATURE-----

--3siQDZowHQqNOShm--