From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!not-for-mail From: Daniel Colascione Newsgroups: gmane.emacs.bugs Subject: bug#17168: 24.3.50; Segfault at mark_object Date: Wed, 02 Apr 2014 17:28:38 -0700 Message-ID: <533CAB36.7080505@dancol.org> References: <87y4zop44m.fsf@yahoo.fr> <533C3AF5.6070502@yandex.ru> <533C6905.9060309@dancol.org> <533C7401.1070203@dancol.org> <87mwg3qwiy.fsf@yahoo.fr> <533C8621.5070805@dancol.org> NNTP-Posting-Host: plane.gmane.org Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="KiMnbAApevhXlWXWn8CcuCO9mUTjnPTx2" X-Trace: ger.gmane.org 1396526194 2565 80.91.229.3 (3 Apr 2014 11:56:34 GMT) X-Complaints-To: usenet@ger.gmane.org NNTP-Posting-Date: Thu, 3 Apr 2014 11:56:34 +0000 (UTC) Cc: Nicolas Richard , Dmitry Antipov , 17168@debbugs.gnu.org To: Stefan Monnier Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Thu Apr 03 13:56:27 2014 Return-path: Envelope-to: geb-bug-gnu-emacs@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 1WVeIm-00075K-Vc for geb-bug-gnu-emacs@m.gmane.org; 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charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On 04/02/2014 04:24 PM, Stefan Monnier wrote: >> It's 32 bytes long, which means that we're trying to mark a pointer in= to >> the middle of the vector. >> The clear-transient-map symbol itself, of course, is live. It's >> perfectly normal and its value slot is set to Qunbound. >=20 > So, IIUC the symbol-function slot of the clear-transient-map symbol > points in the middle of a vector? That's what my analysis seems to indicate. > Since the symbol-function slot of the clear-transient-map symbol is onl= y > set once, I think this means that the vector to which it pointed has > been somehow freed. That's what I speculated last week, but I still have no idea how it would be possible. > Of course that shouldn't be possible: at any previous GC, either the > clear-transient-map symbol was found live and traced (so the vector to > which it pointed shouldn't have been freed) or it wasn't found live, in= > which case the symbol-function slot should have been set to the special= > "dead" value. I added some code to trunk that might help track down the problem. Now we can mark certain objects as "suspicious" (only vectors for now, but that's sufficient); when we free one of these suspicious objects, we record a stack trace. This way, if we crash later, we can figure out where things went wrong. --KiMnbAApevhXlWXWn8CcuCO9mUTjnPTx2 Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.14 (GNU/Linux) Comment: Using GnuPG with Thunderbird - http://www.enigmail.net/ iQIcBAEBAgAGBQJTPKs2AAoJEMAaIROpHW7IYGgP/1IMl27Qp0inSkj4VaawhK3j sWfBYDK8JzKHLgU2fGy5ORn9sS9oN4vwUlhfaAoKIwMNp6xDC6ruLVwFlq2MdYw7 u2Mi2FyLcqFwK0PO7PbUgBINZ1H2JDmvSiWNqaqEsNnu6bAFj4Wk8XNomO8ohZlE XPhXxOHPSnkVKLdFuhYNAfkJa7WZvM04tLIErCDFEwWywANEVFrSwWMTUqSc2j7w AOnkTYzIcVJi6FfvAejT7CD+KWvaACPwZiGhiZvaESLG8MBE3VJP2GCP9n3W5Lu7 DlCHd86RPfmcmBVh4k7EOTnkDwXFFCO7WzzqODTENJ+y+xmE0VeSnHQ0RW/E0Z5+ mIMtpbyW0Jbk8+UN/kx1I4ZfTSbF4thY5CKm3sI0kZurKm0q6ESSeljUd/wWz8rN YxBVczMnfuWo7oXd0Cx4uGgIGglRLiLXWfHzf48s0K3+ruztqnoRlC1S/OxDlFXi E/31KAbggCYg0/RrZHBZPWhyGlO4W5BZ2gSDdBYkWPXgNik0HP2Emd+LP9MS23Hh uo/xfSBp42T1lp9qNWnZ86K+bNQ/uLvoiZaKVV6aYEx+9f+N66JfR/jI8fGypEa3 pxqn/SLFsXdB/6oaEiA4a8XMpRXuSvM/KaRQlWKUavBS7FJzmDhcYokSqWmVn1ef GEp9BN+RHrX5SJr8bcI8 =9T4I -----END PGP SIGNATURE----- --KiMnbAApevhXlWXWn8CcuCO9mUTjnPTx2--