From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.org!.POSTED!not-for-mail From: Eli Zaretskii Newsgroups: gmane.emacs.bugs Subject: bug#33345: 27.0.50; Abort in bidi_cache_iterator_state Date: Tue, 13 Nov 2018 20:05:34 +0200 Message-ID: <83in1097kh.fsf@gnu.org> References: <83in13a9fi.fsf@gnu.org> <8336s69t32.fsf@gnu.org> <83tvkm89sw.fsf@gnu.org> NNTP-Posting-Host: blaine.gmane.org X-Trace: blaine.gmane.org 1542132825 27665 195.159.176.226 (13 Nov 2018 18:13:45 GMT) X-Complaints-To: usenet@blaine.gmane.org NNTP-Posting-Date: Tue, 13 Nov 2018 18:13:45 +0000 (UTC) Cc: 33345@debbugs.gnu.org To: monnier@IRO.UMontreal.CA Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Tue Nov 13 19:13:40 2018 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane.org Original-Received: from lists.gnu.org ([208.118.235.17]) by blaine.gmane.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gMdC0-000758-FO for geb-bug-gnu-emacs@m.gmane.org; Tue, 13 Nov 2018 19:13:40 +0100 Original-Received: from localhost ([::1]:55557 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMdE6-0003ce-LR for geb-bug-gnu-emacs@m.gmane.org; Tue, 13 Nov 2018 13:15:50 -0500 Original-Received: from eggs.gnu.org ([2001:4830:134:3::10]:58059) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMdDk-0003E4-E6 for bug-gnu-emacs@gnu.org; Tue, 13 Nov 2018 13:15:33 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gMd5a-0004Li-Iu for bug-gnu-emacs@gnu.org; Tue, 13 Nov 2018 13:07:07 -0500 Original-Received: from debbugs.gnu.org ([208.118.235.43]:46309) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1gMd5a-0004LV-EM for bug-gnu-emacs@gnu.org; Tue, 13 Nov 2018 13:07:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1gMd5a-0005Pz-58 for bug-gnu-emacs@gnu.org; Tue, 13 Nov 2018 13:07:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Eli Zaretskii Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 13 Nov 2018 18:07:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 33345 X-GNU-PR-Package: emacs X-GNU-PR-Keywords: Original-Received: via spool by 33345-submit@debbugs.gnu.org id=B33345.154213236420761 (code B ref 33345); Tue, 13 Nov 2018 18:07:02 +0000 Original-Received: (at 33345) by debbugs.gnu.org; 13 Nov 2018 18:06:04 +0000 Original-Received: from localhost ([127.0.0.1]:50567 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gMd4d-0005On-P2 for submit@debbugs.gnu.org; Tue, 13 Nov 2018 13:06:03 -0500 Original-Received: from eggs.gnu.org ([208.118.235.92]:46280) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1gMd4b-0005OI-NB for 33345@debbugs.gnu.org; Tue, 13 Nov 2018 13:06:02 -0500 Original-Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1gMd4R-0002mI-Fh for 33345@debbugs.gnu.org; Tue, 13 Nov 2018 13:05:56 -0500 Original-Received: from fencepost.gnu.org ([2001:4830:134:3::e]:45150) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1gMd4O-0002Wq-Rs; Tue, 13 Nov 2018 13:05:49 -0500 Original-Received: from [176.228.60.248] (port=3288 helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:RSA_AES_256_CBC_SHA1:256) (Exim 4.82) (envelope-from ) id 1gMd4K-0002rg-0g; Tue, 13 Nov 2018 13:05:47 -0500 In-reply-to: <83tvkm89sw.fsf@gnu.org> (message from Eli Zaretskii on Mon, 12 Nov 2018 19:50:23 +0200) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 208.118.235.43 X-BeenThere: bug-gnu-emacs@gnu.org List-Id: "Bug reports for GNU Emacs, the Swiss army knife of text editors" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.org gmane.emacs.bugs:152352 Archived-At: > Date: Mon, 12 Nov 2018 19:50:23 +0200 > From: Eli Zaretskii > Cc: 33345@debbugs.gnu.org > > And one more question: does the system/configuration where you see the > crash differ from the others in the font used to display the offending > text? The shaping of Arabic could depend on the font being used, due > to differences in OTF features supported by the fonts. I've thought about this some more, and I really don't understand how this could happen. The offending call to bidi_cache_iterator_state is from here: /* Prepare the sentinel iterator state, and cache it. When we bump into it, scanning backwards, we'll know that the last non-base level is exhausted. */ if (bidi_cache_idx == bidi_cache_start) { bidi_copy_it (&sentinel, bidi_it); if (bidi_it->first_elt) { sentinel.charpos--; /* cached charpos needs to be monotonic */ sentinel.bytepos--; sentinel.ch = '\n'; /* doesn't matter, but why not? */ sentinel.ch_len = 1; sentinel.nchars = 1; } bidi_cache_iterator_state (&sentinel, 1, 0); <<<<<<<<<<<<<<<< } But this means that the cache is empty, and we can never scan back (scan_dir = -1) when the cache is empty. So something very strange happened there. Instead of me asking you gobs of questions, perhaps you could give me an ssh login on that system, and arrange for a GDB session which already hit the call to emacs_abort to be in a state where I can switch to it after logging in (with 'screen' or 'tmux', I think). Then I could look around and see if I find out some clues. Thanks.