From mboxrd@z Thu Jan 1 00:00:00 1970 Path: news.gmane.io!.POSTED.blaine.gmane.org!not-for-mail From: Francesco =?UTF-8?Q?Potort=C3=AC?= Newsgroups: gmane.emacs.bugs Subject: bug#44930: I can reproduce it Date: Tue, 01 Dec 2020 18:19:54 +0100 Message-ID: References: <83pn3timo4.fsf@gnu.org> Mime-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit Injection-Info: ciao.gmane.io; posting-host="blaine.gmane.org:116.202.254.214"; logging-data="3305"; mail-complaints-to="usenet@ciao.gmane.io" Cc: 44930@debbugs.gnu.org To: Eli Zaretskii Original-X-From: bug-gnu-emacs-bounces+geb-bug-gnu-emacs=m.gmane-mx.org@gnu.org Tue Dec 01 18:42:30 2020 Return-path: Envelope-to: geb-bug-gnu-emacs@m.gmane-mx.org Original-Received: from lists.gnu.org ([209.51.188.17]) by ciao.gmane.io with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1kk9fa-0000j6-AW for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 01 Dec 2020 18:42:30 +0100 Original-Received: from localhost ([::1]:43618 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kk9fZ-0004ou-76 for geb-bug-gnu-emacs@m.gmane-mx.org; Tue, 01 Dec 2020 12:42:29 -0500 Original-Received: from eggs.gnu.org ([2001:470:142:3::10]:36452) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kk9Ko-0007Js-RR for bug-gnu-emacs@gnu.org; Tue, 01 Dec 2020 12:21:03 -0500 Original-Received: from debbugs.gnu.org ([209.51.188.43]:49886) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1kk9Ko-0002Rg-JH for bug-gnu-emacs@gnu.org; Tue, 01 Dec 2020 12:21:02 -0500 Original-Received: from Debian-debbugs by debbugs.gnu.org with local (Exim 4.84_2) (envelope-from ) id 1kk9Ko-0004qB-Dp for bug-gnu-emacs@gnu.org; Tue, 01 Dec 2020 12:21:02 -0500 X-Loop: help-debbugs@gnu.org Resent-From: Francesco =?UTF-8?Q?Potort=C3=AC?= Original-Sender: "Debbugs-submit" Resent-CC: bug-gnu-emacs@gnu.org Resent-Date: Tue, 01 Dec 2020 17:21:02 +0000 Resent-Message-ID: Resent-Sender: help-debbugs@gnu.org X-GNU-PR-Message: followup 44930 X-GNU-PR-Package: emacs Original-Received: via spool by 44930-submit@debbugs.gnu.org id=B44930.160684320118491 (code B ref 44930); Tue, 01 Dec 2020 17:21:02 +0000 Original-Received: (at 44930) by debbugs.gnu.org; 1 Dec 2020 17:20:01 +0000 Original-Received: from localhost ([127.0.0.1]:33199 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kk9Jp-0004o4-41 for submit@debbugs.gnu.org; Tue, 01 Dec 2020 12:20:01 -0500 Original-Received: from smtp-clients2.isti.cnr.it ([146.48.28.37]:42630) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from ) id 1kk9Jl-0004np-CP for 44930@debbugs.gnu.org; Tue, 01 Dec 2020 12:19:59 -0500 Original-Received: from tucano.isti.cnr.it (tucano.isti.cnr.it [146.48.81.102]) (Authenticated sender: pot) by smtp-clients2.isti.cnr.it (Postfix) with ESMTPSA id 6D825B0838; Tue, 1 Dec 2020 18:19:55 +0100 (CET) X-Virus-Status: Clean X-Virus-Scanned: clamav-milter 0.102.4 at smtp-out.isti.cnr.it Original-Received: from pot by tucano.isti.cnr.it with local (Exim 4.94) (envelope-from ) id 1kk9Ji-00BycL-VL; Tue, 01 Dec 2020 18:19:54 +0100 In-Reply-To: <83pn3timo4.fsf@gnu.org> (eliz@gnu.org) X-fingerprint: 4B02 6187 5C03 D6B1 2E31 7666 09DF 2DC9 BE21 6115 X-BeenThere: debbugs-submit@debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list 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-mx.org@gnu.org Original-Sender: "bug-gnu-emacs" Xref: news.gmane.io gmane.emacs.bugs:194753 Archived-At: >> In this moment I have a *w3m* buffer on a live Emacs. If I switch to it >> on a text frame, everything is well. If I switch to it on an X display, >> the frame dies (but Emacs survives). The error is >> >> X protocol error: BadMatch (invalid parameter attributes) on protocol request 73 >> >> until I don't kill the buffer, I can reproduce the error at will. I >> have no idea how to debug it. If I am instructed, I can try until Emacs >> is alive. > >etc/DEBUG has some instructions for debugging X protocol errors; >search for "If you encounter X protocol errors". Ok. I fear I will not be able to do that quickly. >In addition to what that says, it would be beneficial to understand >what kind of X request is "request 73". According to http://www.rahul.net/kenton/xproto/xrequests.html 73 is the X protocol GetImage call. According to https://www.x.org/wiki/guide/concepts/#index2h3, this is seldom used, for example for making screenshots or for redrawing. The second usage could explain why it happens when I switch buffer and why the debugger points to the internal C function redisplay_internal() The XGetImage function is called twice from gtkutil.c and thrice from image.c, so one of these is apparently failing. According to https://www.x.org/releases/X11R7.7/doc/xproto/x11protocol.html#requests:GetImage the call may return a Match error when the pixmap or window to be returned do not satisfy certain geometric criteria. This is strange, because the error happens only when I switch to a specific buffer, which makes me think that it depends on the buffer contents. Is there a way to save the buffer contents including attributes (fonts, overlays and other things that I do not know about) to disk, so that I can easily recreate a buffer with the strange property of causing this error?