From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Daniel Colascione Newsgroups: gmane.emacs.devel Subject: Re: GC and stack marking Date: Tue, 20 May 2014 12:12:45 -0700 Message-ID: <537BA92D.50204@dancol.org> References: <83a9add91p.fsf@gnu.org> <8338g4bd7m.fsf@gnu.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="9Vxl59plBGJbKhK7xfqpFFSNSQUFXxfWR" X-Trace: ger.gmane.org 1400613184 10379 80.91.229.3 (20 May 2014 19:13:04 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Tue, 20 May 2014 19:13:04 +0000 (UTC) Cc: fabrice.popineau@gmail.com, emacs-devel@gnu.org To: Eli Zaretskii , Stefan Monnier Original-X-From: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Tue May 20 21:12:57 2014 Return-path: Envelope-to: ged-emacs-devel@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by plane.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1WmpT6-0002m6-NN for ged-emacs-devel@m.gmane.org; Tue, 20 May 2014 21:12:56 +0200 Original-Received: from localhost ([::1]:55032 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmpT6-000323-3F for ged-emacs-devel@m.gmane.org; Tue, 20 May 2014 15:12:56 -0400 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:56402) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmpT2-00031g-8S for emacs-devel@gnu.org; Tue, 20 May 2014 15:12:53 -0400 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WmpT1-0008Tv-9N for emacs-devel@gnu.org; Tue, 20 May 2014 15:12:52 -0400 Original-Received: from dancol.org ([2600:3c01::f03c:91ff:fedf:adf3]:45755) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WmpSz-0008TK-Jl; Tue, 20 May 2014 15:12:49 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=dancol.org; s=x; h=Content-Type:In-Reply-To:References:Subject:CC:To:MIME-Version:From:Date:Message-ID; bh=GHwKlnFSW3TDEUxhazSj+pYuooEe2kpxfcnxy8zJ1LE=; b=qnTFhON1aK0yI+NXy4k82c3TSNOZ4CFltloLwv/INH/0AGyXhu5cF11d4+GY8WeQZrcgRPdegw/iefpl+gguOmazGNY7lBbq2Bb7VQbDOnj3Pxe+hVdlfCUqRKkJVy8DqrQ2uj8OH+eYk0Ku/ZoKKB9roAcdemVdB8VYSpNEn5wh5tuS/fBFc8fikKSk3H6IfNrUALimrkSgbPE4BD+cJ3qGD/jxhQvN5F7MaTNVzQxLh5ATsMQcjBFBx+j5kgbHGPcl/zW+Tg2Sjeuhaxswtqbdnte5TwtfVRi7Xv94m4FQ6mo7BRhvQx7AozU0Q/qx8cyFRgyHthy5bqM2DFP+eg==; Original-Received: from [2601:8:b240:264::2b1] by dancol.org with esmtpsa (TLS1.0:DHE_RSA_AES_128_CBC_SHA1:128) (Exim 4.82) (envelope-from ) id 1WmpSy-0007HM-8R; Tue, 20 May 2014 12:12:48 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 In-Reply-To: <8338g4bd7m.fsf@gnu.org> X-Enigmail-Version: 1.6 X-detected-operating-system: by eggs.gnu.org: Error: Malformed IPv6 address (bad octet value). X-Received-From: 2600:3c01::f03c:91ff:fedf:adf3 X-BeenThere: emacs-devel@gnu.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: "Emacs development discussions." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Original-Sender: emacs-devel-bounces+ged-emacs-devel=m.gmane.org@gnu.org Xref: news.gmane.org gmane.emacs.devel:171965 Archived-At: This is an OpenPGP/MIME signed message (RFC 4880 and 3156) --9Vxl59plBGJbKhK7xfqpFFSNSQUFXxfWR Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 05/20/2014 09:57 AM, Eli Zaretskii wrote: >> From: Stefan Monnier >> Cc: emacs-devel@gnu.org, Fabrice Popineau = >> Date: Tue, 20 May 2014 09:44:05 -0400 >> >>> The short version of the question is: is it possible that a Lisp >>> object which is no longer referenced by anything won't be GC'ed >>> because it is marked by mark_stack due to some kind of coincidence? >> >> Yes, of course, it's what makes a conservative marking conservative. >=20 > I have nothing against conservative, but this failure to GC is too > spectacular to ignore. >=20 >>> So the huge hash-table gets dumped into the emacs executable, and >> >> That's bad luck, indeed. >> >>> causes all kinds of trouble in the dumped Emacs. >> >> But it shouldn't cause any trouble (other than extra memory use). >=20 > It does, due to all kinds of subtleties. The result is that the > large_vectors linked list gets dumped with a pointer to a non-existent > memory, and the dumped Emacs then crashes on the first GC when it > tries to traverse that linked list. Can you elaborate on how that happens? This behavior sounds like a plain GC bug. --9Vxl59plBGJbKhK7xfqpFFSNSQUFXxfWR Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1 Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTe6ktAAoJEMAaIROpHW7IcbcP/RtVE31A/9fSsDkUx1i0BSTP mAsT7nhQlSa6ClVlbbyOZwEERkObjcW0HEhQ0A0HLV/JgxV9tVBS/XsTmJy/MO0k Ubcf2h21k72LQNGpZJ15irlToAzC6XmHFGYvuXgiOXtTK366vUZTMJwKaVILGROD Fb8MB8dyVGz6C27fBawc2rFp4Mdg9C0w+PmRv4PyUwhtcQpmwO+C64TwqVCof+FR deHIDcFR2wZnNDo+gWZ7WFDPYsuqNSy9BcPgpfC9YHQvgrT4L5+UCd6hhJMw96Jo eD2vr0IDqqrKB0bsYLXDIXtaMsD2uejOSx7RLerYO9946uXDauc2Or4+yq7fFnn9 M/5Vu5iTOwqRVgDeW9LIAVNhzUA9XTxQoT03zSDgXYHiA8lvrN3T8kxEcLpamAuV VoJPWwlDXUASpDwpq0MIigdminPFU5sKCbDQ0v9k1uC9+ztR3Kdf2FgfwRmYWtj1 /oDFx1VnKBcI9A1UTnfaH6fSJE4q6BG/3DDz9xdsN7H6Ie8pX0T3sseU1LrYpOZH op6ZgRou0kF7v+GW98fbxEVYe1xIATYRT355wiVZECUT7snd4ghnknMJ9ET4etC6 1tKxi2j5g9MrBp3+B1FFLMh+I/QpnX9XsnWXTwyMg9bLZPSP4hd4krh+JejZxmRF ODvy2+wqztP0O3wR36iE =ugP+ -----END PGP SIGNATURE----- --9Vxl59plBGJbKhK7xfqpFFSNSQUFXxfWR--