Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 12:24:21 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 07:24:20 2023 Received: from localhost ([127.0.0.1]:53972 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabnI-0005wF-DZ for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:24:20 -0500 Received: from server.qxqx.de ([178.63.65.180]:38285 helo=mail.qxqx.de) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1pabnG-0005w0-P6 for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:24:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=jbyTXXhNVn+OLvkSRp+fZC0ay03PeXP5uN47QtAZhN0=; b=fPBrZ6QKr+Fxb1Gm+KNHrE/OiA tUhoQXkxyYofMiVU2ZTgW5hoj94ks1CDAnHEz8M3gumf8Epnf8kqmRc363mNxMO7+bQcdRXC40mIs cyCTZoovWvwveOmtqrmo6OLEuL6PDALUiwNiYm3SCnQKJdbLVBZS21FWtGWrgWmJaosk=; Message-ID: <20b91f20-1ed8-c38f-0165-b0eb3de1ee80@HIDDEN> Date: Fri, 10 Mar 2023 13:24:08 +0100 MIME-Version: 1.0 Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name Content-Language: en-US To: Eli Zaretskii <eliz@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> <87fsacx2qf.fsf@HIDDEN> <3a9f613f-baa9-2c48-f779-aaf43363a865@HIDDEN> <83mt4kztwe.fsf@HIDDEN> From: Daniel Mendler <mail@HIDDEN> In-Reply-To: <83mt4kztwe.fsf@HIDDEN> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: philipk@HIDDEN, michael_heerdegen@HIDDEN, rpluim@HIDDEN, gregory@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, arstoffel@HIDDEN X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) On 3/10/23 13:13, Eli Zaretskii wrote: >> Date: Fri, 10 Mar 2023 12:36:17 +0100 >> Cc: Gregory Heytings <gregory@HIDDEN>, >> Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, >> monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii >> <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN> >> From: Daniel Mendler <mail@HIDDEN> >> >>> /* Number of characters in string; MSB is used as the mark bit. */ >>> ptrdiff_t size; >>> /* If nonnegative, number of bytes in the string (which is multibyte). >>> If negative, the string is unibyte: >>> -1 for data normally allocated >>> -2 for data in rodata (C string constants) >>> -3 for data that must be immovable (used for bytecode) */ >>> ptrdiff_t size_byte; >> >> Thanks! That's good. Given that a read only flag already exists, it is >> easy to fix the issue. We just have to make sure that the size is >> negative for the symbol names and add a check in `aset`. > > Let's not do that! Why not? There won't be a performance cost.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 12:13:47 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 07:13:47 2023 Received: from localhost ([127.0.0.1]:53962 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabd4-0005ey-PP for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:13:47 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51716) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1pabd4-0005ek-1L for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:13:46 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabcy-0004hg-1N; Fri, 10 Mar 2023 07:13:40 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=SQWut6f92KeOBKfZ1GrTEWhLlWQt0zsMC1qta7Vk5q8=; b=bs1UELqYjoaU REjIYco8BM3Hs1NgGBKziBqAwCsGkGeYwhSFnScawlYNXxemcCBpdEmvazTlrfoKWX3hgEv8RPs/r +vw8m4WSOtffkFWmPhcqaCLEovNs1mBCiaUN/XY1YMbG3yxGwQuWJqWKCXKgETHO9SEazNsIBBVv7 WYd8IWGVwg35S2QeF2HDIZi9YtXwhizh2rYCfnsHLu0Wm5H7REGmJ0J/Sjm6+RWpOAOdWILNXd6Vf NFwosg4laLwJgt5tbDHdy5PAxVSUKXMLVLz39Yk/l1QG4lh+3BNoZeMXmJ6AVY+VSisFuDmqqr1rf JPlVlUy7gbaUhqu2roGBRw==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabcx-0000b4-A8; Fri, 10 Mar 2023 07:13:39 -0500 Date: Fri, 10 Mar 2023 14:13:21 +0200 Message-Id: <83mt4kztwe.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Daniel Mendler <mail@HIDDEN> In-Reply-To: <3a9f613f-baa9-2c48-f779-aaf43363a865@HIDDEN> (message from Daniel Mendler on Fri, 10 Mar 2023 12:36:17 +0100) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> <87fsacx2qf.fsf@HIDDEN> <3a9f613f-baa9-2c48-f779-aaf43363a865@HIDDEN> X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: philipk@HIDDEN, michael_heerdegen@HIDDEN, rpluim@HIDDEN, gregory@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, arstoffel@HIDDEN X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > Date: Fri, 10 Mar 2023 12:36:17 +0100 > Cc: Gregory Heytings <gregory@HIDDEN>, > Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, > monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii > <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN> > From: Daniel Mendler <mail@HIDDEN> > > > /* Number of characters in string; MSB is used as the mark bit. */ > > ptrdiff_t size; > > /* If nonnegative, number of bytes in the string (which is multibyte). > > If negative, the string is unibyte: > > -1 for data normally allocated > > -2 for data in rodata (C string constants) > > -3 for data that must be immovable (used for bytecode) */ > > ptrdiff_t size_byte; > > Thanks! That's good. Given that a read only flag already exists, it is > easy to fix the issue. We just have to make sure that the size is > negative for the symbol names and add a check in `aset`. Let's not do that!
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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To: Robert Pluim <rpluim@HIDDEN>
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Mar 2023 12:30:48 +0100)
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
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> From: Robert Pluim <rpluim@HIDDEN>
> Cc: Gregory Heytings <gregory@HIDDEN>, Philip Kaludercic
> <philipk@HIDDEN>, michael_heerdegen@HIDDEN,
> monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii
> <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN>
> Date: Fri, 10 Mar 2023 12:30:48 +0100
>
> diff --git a/src/lisp.h b/src/lisp.h
> index 1276285e2f2..80bbb047824 100644
> --- a/src/lisp.h
> +++ b/src/lisp.h
> @@ -1685,6 +1685,8 @@ SREF (Lisp_Object string, ptrdiff_t index)
> INLINE void
> SSET (Lisp_Object string, ptrdiff_t index, unsigned char new)
> {
> + if (XSTRING (string)->u.s.size_byte == -2)
> + Fsignal (Qsetting_constant, string);
"Setting constant" is misleading.
And again, why do that at all? It's a waste of cycles, incurred on
_everyone_, for an extremely rare use case that is explicitly
discouraged. We are not the TSA, and should not adopt their policy of
punishing the innocent 99.99% on behalf of a handful of villains.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 12:10:07 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 07:10:07 2023 Received: from localhost ([127.0.0.1]:53946 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabZX-0005Z4-FF for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:10:07 -0500 Received: from eggs.gnu.org ([209.51.188.92]:37940) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1pabZV-0005Xu-E6 for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:10:06 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabZP-0003XU-Bp; Fri, 10 Mar 2023 07:09:59 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=MIME-version:References:Subject:In-Reply-To:To:From: Date; bh=QNPwb3hS4u60incqkxSCtOp+/TwTOjyKvBbRH3hx8Tw=; b=IbX0aVOp5MPOLST13ucl gL1UNiN+7aVfPcFcmkiLjvBI0RQj+I9MxNMwSFEFthLZfLNEGPDbz3xQhCanhumh6BbvqOckY4o4R q2742w0gb9/unUpuHbJFF/2ss9G822CIDqrYWy0ALkY9RtR3qKspp8HPELbew2lSKi4X1yk0BPC7g Ox7gk5UsGgb9w4LtQOs1t1g1kYZxINuqOlxtEx5eoFjzE9/7A3oOZrc9+UcdLVJd+B37gpFur2snl 6f4s2R+aTUORAhdf0oK5kWv7l7vpao4286VLXhhC4sJp30N9+lKl3vqT3/ZhrPIbKlitANy4fbI7Q HYYBfGpiYlYyYQ==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabZO-0008De-ST; Fri, 10 Mar 2023 07:09:59 -0500 Date: Fri, 10 Mar 2023 14:09:41 +0200 Message-Id: <83pm9gzu2i.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Augusto Stoffel <arstoffel@HIDDEN> In-Reply-To: <87v8j84zp1.fsf@HIDDEN> (message from Augusto Stoffel on Fri, 10 Mar 2023 12:23:54 +0100) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> <87v8j84zp1.fsf@HIDDEN> MIME-version: 1.0 Content-type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: philipk@HIDDEN, michael_heerdegen@HIDDEN, mail@HIDDEN, gregory@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > From: Augusto Stoffel <arstoffel@HIDDEN> > Cc: Gregory Heytings <gregory@HIDDEN>, Eli Zaretskii <eliz@HIDDEN>, > Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, > monnier@HIDDEN, 62009 <at> debbugs.gnu.org > Date: Fri, 10 Mar 2023 12:23:54 +0100 > > On Fri, 10 Mar 2023 at 12:09, Daniel Mendler wrote: > > > On 3/10/23 11:59, Gregory Heytings wrote: > >> That would also come with a performance overhead, as there is currently no > >> way to distinguist strings that are used for symbol names from other > >> strings. Not to mention the added complexity in the code. > > > > One could check if the string is located in read-only memory. Or one > > could add a flag bit to the string data structure (and possibly to other > > data structures too). Freezing data structures such that they become > > read-only is a generally useful feature. There won't be any performance > > overhead of the check since a branch not taken is fast thanks to the > > branch predictor. > > Note also that in-place modification of strings is arbitrarily costly, > cf. (aset "ascii" 0 ?😼). Not to mention that it's rarely a good or > necessary move to make, as far as programming style is concerned. Be this tru as it may, we will not constrain what Lisp programs can legitimately do just because we think it is "rarely a good move". That's against our long-time policy, which is explain why something might not be a good idea, but otherwise don't block that, letting the unwise cope with the consequences of their unwise actions. IOW, we encourage Lisp programmers to DTRT and not use dangerous practices, but don't block them if they want to.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 12:00:46 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 07:00:45 2023 Received: from localhost ([127.0.0.1]:53916 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabQT-0005GV-KO for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:00:45 -0500 Received: from server.qxqx.de ([178.63.65.180]:49465 helo=mail.qxqx.de) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1pabQQ-0005GD-Sz for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 07:00:44 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=Mk+E0wiRRNAzd3G290ADo1Z4FbXBwp1p3zDiR/nKCZo=; b=FtBlrWS8GM5fnNbpgyScipkJVu H3UUreG4Iwf46OHfpgprWL4X7rdjs3nRYJYPsguGiAFqDmbdMtafyqAMidDDFA6KnCVYJGXOiUr9w Psrx8WspHbanM0VPYuxQUwpP1ccKF3jB8B45g+B2De9T8qOgHjeYicqiLxFLVUYSf76k=; Message-ID: <e6451c43-480f-4a07-9fee-084116fbe352@HIDDEN> Date: Fri, 10 Mar 2023 13:00:34 +0100 MIME-Version: 1.0 Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name To: Eli Zaretskii <eliz@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <87ilf9571k.fsf@HIDDEN> <87edpx56xm.fsf@HIDDEN> <83wn3ozuyn.fsf@HIDDEN> Content-Language: en-US From: Daniel Mendler <mail@HIDDEN> In-Reply-To: <83wn3ozuyn.fsf@HIDDEN> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: philipk@HIDDEN, michael_heerdegen@HIDDEN, Robert Pluim <rpluim@HIDDEN>, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Augusto Stoffel <arstoffel@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) On 3/10/23 12:50, Eli Zaretskii wrote: > Why bother? Emacs is not in the business of preventing Lisp > programmers from shooting themselves in the foot, certainly not when > that incurs runtime overhead, even a small one. Of course Elisp is in the business of preventing programmers from shooting themselves in the foot, otherwise we would extend Emacs in C. It is not only that Elisp is easier to write thanks to macros and other conveniences, but also because it is safer! I fully agree with you that we should not introduce a performance regression, in particular not one which increases GC pressure badly. Furthermore I agree that this is a minor bug which only occurs as an edge case when some specific strings are mutated. However the cost of fixing this bug is minor, since Elisp already supports read-only data stuctures as pointed out by Robert. We may only need an additional check in aset which won't introduce significant costs thanks to the branch predictor of CPUs. As Augusto pointed out, aset on strings can already be very costly because the string must be reallocated. In comparison, the additional check will be free. Daniel
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 11:59:58 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 06:59:58 2023 Received: from localhost ([127.0.0.1]:53911 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabPh-0005D3-U8 for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:59:58 -0500 Received: from eggs.gnu.org ([209.51.188.92]:58708) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1pabPg-0005Cg-K9 for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:59:57 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabPa-0000On-Jn; Fri, 10 Mar 2023 06:59:50 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=3dbOtZE0CcsU/n1JSEqulQf/qLsEWvxe3jt03Lkmw98=; b=X6UoKWf0GLjb YM8N4fbmGMjf0BGlSudXqjz+sn1P1piZDKmxCd8kOsCEim4WgZYIFk/pTvf/w6TRhE8pQANIK11yI idmTL7OYk4NdJtmQlPs1McyJDyIId9FUX289bFXbUae/n8xHKMobGbjexukLwQXFxO2TJqMmyD0VC 9tevgIOXdDTlu39Tgoy+xlZhalGE1NiTRYuQ8LWhLriTQAYLua/4nszCVUCGGK2vO3NNJLW4fbg/H M1/cMxDXyHvttSNp/J6/TQR6NplYKwvxd2HhAC91D/JVTBiUP0XaR28+okJ7X+XA0KUN3lJsVaY9W /jDjYnkt/+ygr3QOUGhF9A==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabPY-000848-V1; Fri, 10 Mar 2023 06:59:50 -0500 Date: Fri, 10 Mar 2023 13:59:28 +0200 Message-Id: <83sfeczujj.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Gregory Heytings <gregory@HIDDEN> In-Reply-To: <16ecbe9ea85b22d008fd@HIDDEN> (message from Gregory Heytings on Fri, 10 Mar 2023 10:59:03 +0000) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: philipk@HIDDEN, michael_heerdegen@HIDDEN, mail@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, arstoffel@HIDDEN X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > Date: Fri, 10 Mar 2023 10:59:03 +0000 > From: Gregory Heytings <gregory@HIDDEN> > cc: Eli Zaretskii <eliz@HIDDEN>, Philip Kaludercic <philipk@HIDDEN>, > michael_heerdegen@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, > Augusto Stoffel <arstoffel@HIDDEN> > > > Creating a string is not a good idea since it will lead to an > > unacceptably large performance overhead. > > Is "symbol-name" a function that is used in performance-critical code? Yes, it is. Just grep for it. We even call it from C quite a few times. And processing is just one aspect of that; memory and GC is another, not less important. > And did you actually measure that performance overhead before concluding > that it it "unacceptably large"? Anything greater than zero is unacceptably large from where I stand, when the other side of the balance is the use case against which this protects. > > Raising an exception upon modification would be the best approach. > > That would also come with a performance overhead, as there is currently no > way to distinguist strings that are used for symbol names from other > strings. Not to mention the added complexity in the code. Which is why we should do neither.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 11:59:58 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 06:59:57 2023 Received: from localhost ([127.0.0.1]:53909 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabPh-0005D0-Ma for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:59:57 -0500 Received: from heytings.org ([95.142.160.155]:34082) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <gregory@HIDDEN>) id 1pabPg-0005Co-1D for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:59:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heytings.org; s=20220101; t=1678449595; bh=ZSzS8OI8cKLhZefvn0uCNvCnkmCij2kh0dlB8Cd2SUY=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:From; b=7DL72jzCoN2NPztbMeWKNX3W84qXzTasdehfKRqybxMauyGwM3ngz+GT1Qdu3GU+Q 3TQUNnqsMNsmU6D4VTI/AGYdVIYM1KsYFBSww6M7fE7tftRNumrOii44UVT32Jx/4u VIW00Zu66DXBcTewNbsryS3S8O6xnc/RIQBLTUguJFVQCclRyNi3cuXAksxSdEIeMm 3V5fAG/VsRyiL7PGUO1Np57UQD6ZLnLEG2cRv/AefyC5yzH6D2R3IEyQMRnUn34jZT ps2fZW4bk4F/v1cisEPMKF1eLU5P/gDY4JnKfBQ8VxAJx5H8nDOVvDIXTDLLZOFQWa cXIFdEeScY4aA== Date: Fri, 10 Mar 2023 11:59:54 +0000 From: Gregory Heytings <gregory@HIDDEN> To: Eli Zaretskii <eliz@HIDDEN> Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name In-Reply-To: <83v8j8zutj.fsf@HIDDEN> Message-ID: <16ecbe9ea800de5b4089@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <83v8j8zutj.fsf@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed X-Spam-Score: -0.0 (/) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, mail@HIDDEN, philipk@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -1.0 (-) > > No, we will NOT increase GC pressure in Emacs just because someone could > do a silly and nonsensical thing. No way. > I agree with you that this is not really a bug, so doing nothing is fine for me, too.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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Date: Fri, 10 Mar 2023 11:57:43 +0000
From: Gregory Heytings <gregory@HIDDEN>
To: Robert Pluim <rpluim@HIDDEN>
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
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>
> diff --git a/src/lisp.h b/src/lisp.h
> index 1276285e2f2..80bbb047824 100644
> --- a/src/lisp.h
> +++ b/src/lisp.h
> @@ -1685,6 +1685,8 @@ SREF (Lisp_Object string, ptrdiff_t index)
> INLINE void
> SSET (Lisp_Object string, ptrdiff_t index, unsigned char new)
> {
> + if (XSTRING (string)->u.s.size_byte == -2)
> + Fsignal (Qsetting_constant, string);
> SDATA (string)[index] = new;
> }
> INLINE ptrdiff_t
>
That flag is useful only for the first part of the bug: setting the symbol
name of a function defined in C. It does not prevent changing symbol
names in general, e.g. (aset (symbol-name 'find-file) 1 ?o).
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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Heytings on Fri, 10 Mar 2023 09:40:31 +0000)
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
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> Date: Fri, 10 Mar 2023 09:40:31 +0000
> From: Gregory Heytings <gregory@HIDDEN>
> cc: Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN,
> mail@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org
>
>
> Instead of raising a signal, I suggest:
>
> diff --git a/src/data.c b/src/data.c
> index 0f1d881e00b..76867d6787e 100644
> --- a/src/data.c
> +++ b/src/data.c
> @@ -780,7 +780,7 @@ DEFUN ("symbol-name", Fsymbol_name, Ssymbol_name, 1,
> 1, 0,
>
> CHECK_SYMBOL (symbol);
> name = SYMBOL_NAME (symbol);
> - return name;
> + return build_string (SSDATA (name));
> }
>
> DEFUN ("bare-symbol", Fbare_symbol, Sbare_symbol, 1, 1, 0,
No, we will NOT increase GC pressure in Emacs just because someone
could do a silly and nonsensical thing. No way.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 11:49:32 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 06:49:32 2023 Received: from localhost ([127.0.0.1]:53882 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pabFc-0004sW-3e for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:49:32 -0500 Received: from eggs.gnu.org ([209.51.188.92]:32990) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1pabFa-0004sF-Dr for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:49:30 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabFT-0006ma-Og; Fri, 10 Mar 2023 06:49:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=2t1X6GvDj2QV49uwcTjHTFv48CO4HBs9UjwU/h1KEtI=; b=l56Re7/u9kVZ qFs6fxaqRHHrq26JJNa4YzQpXcAsBwKza0ljatXFptou0s8Z9AHcwNUdDQfmmTftClkAL7QwOU7GQ ja/tDZJHayT2urKA0CSivYX2eA+kOnbUSaGOOL0blzkVBeDOj6CP453hXLAkcxIkivHc1zyR4z75q jnH9ytRKcDWTTIlSgX0o4M5B3a/clc37M/0gfGmbx8N/Zbqk1be8wcb7MbexXYbsQVTY+6cJaxG1+ L1hUtJa5jpYHdfywRQxT+Kqs7p7lYdF5lyClJcQL3ktFVBjRupoiY11s7HorFwbG8Mpx8aQ2uv/JZ 0/PHewDuC79nF7urKGP2fA==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pabFT-00020N-7E; Fri, 10 Mar 2023 06:49:23 -0500 Date: Fri, 10 Mar 2023 13:49:04 +0200 Message-Id: <83y1o4zv0v.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Augusto Stoffel <arstoffel@HIDDEN> In-Reply-To: <87ilf9571k.fsf@HIDDEN> (message from Augusto Stoffel on Fri, 10 Mar 2023 09:45:11 +0100) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <87ilf9571k.fsf@HIDDEN> X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, mail@HIDDEN, philipk@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > From: Augusto Stoffel <arstoffel@HIDDEN> > Cc: Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, > mail@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org > Date: Fri, 10 Mar 2023 09:45:11 +0100 > > On Fri, 10 Mar 2023 at 09:11, Eli Zaretskii wrote: > > >> Is it not possible to detect this before the illegal memory access, and > >> raise a signal in Emacs Lisp? > > > > It won't be easy, if at all possible. And I'm not sure we even want > > to do that. What would be the purpose of supporting such a use of > > Emacs? > > What is the purpose of supporting mutation of symbol names in general? We don't. Whoever does this is on their own.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 11:36:29 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 06:36:29 2023 Received: from localhost ([127.0.0.1]:53864 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pab2z-0004OT-28 for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:36:29 -0500 Received: from server.qxqx.de ([178.63.65.180]:53847 helo=mail.qxqx.de) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1pab2x-0004O8-70 for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:36:27 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=GnYHqRI1SDwqJyNelNdWFM55hN+/qbDqWXuNGeo1ZOc=; b=JQhizzC/Bg4432u8VUZDLtz5Vv vgZHp5vvhRgOCDm6ek1WUZidsjnaUFe5vUDI6CtL1JQpYXkh3xaquNNCemOFU4NowfAjATl9Fj+92 yVoNoTz78SYy7Y8ipBr4TpJ45qKcL91qATgSGdNbP+65uv4GYwAo8IEldVsTK46n4S3o=; Message-ID: <3a9f613f-baa9-2c48-f779-aaf43363a865@HIDDEN> Date: Fri, 10 Mar 2023 12:36:17 +0100 MIME-Version: 1.0 Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name Content-Language: en-US To: Robert Pluim <rpluim@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> <87fsacx2qf.fsf@HIDDEN> From: Daniel Mendler <mail@HIDDEN> In-Reply-To: <87fsacx2qf.fsf@HIDDEN> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, Gregory Heytings <gregory@HIDDEN>, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) On 3/10/23 12:30, Robert Pluim wrote: >>>>>> On Fri, 10 Mar 2023 12:09:59 +0100, Daniel Mendler <mail@HIDDEN> said: > > Daniel> One could check if the string is located in read-only memory. Or one > Daniel> could add a flag bit to the string data structure (and possibly to other > Daniel> data structures too). Freezing data structures such that they become > Daniel> read-only is a generally useful feature. There won't be any performance > Daniel> overhead of the check since a branch not taken is fast thanks to the > Daniel> branch predictor. > > We already have such a flag: > > /* Number of characters in string; MSB is used as the mark bit. */ > ptrdiff_t size; > /* If nonnegative, number of bytes in the string (which is multibyte). > If negative, the string is unibyte: > -1 for data normally allocated > -2 for data in rodata (C string constants) > -3 for data that must be immovable (used for bytecode) */ > ptrdiff_t size_byte; Thanks! That's good. Given that a read only flag already exists, it is easy to fix the issue. We just have to make sure that the size is negative for the symbol names and add a check in `aset`. Daniel
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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From: Robert Pluim <rpluim@HIDDEN>
To: Daniel Mendler <mail@HIDDEN>
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
In-Reply-To: <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> (Daniel
Mendler's message of "Fri, 10 Mar 2023 12:09:59 +0100")
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<9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN>
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Date: Fri, 10 Mar 2023 12:30:48 +0100
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>>>>> On Fri, 10 Mar 2023 12:09:59 +0100, Daniel Mendler <mail@HIDDEN> said:
Daniel> One could check if the string is located in read-only memory. Or one
Daniel> could add a flag bit to the string data structure (and possibly to other
Daniel> data structures too). Freezing data structures such that they become
Daniel> read-only is a generally useful feature. There won't be any performance
Daniel> overhead of the check since a branch not taken is fast thanks to the
Daniel> branch predictor.
We already have such a flag:
/* Number of characters in string; MSB is used as the mark bit. */
ptrdiff_t size;
/* If nonnegative, number of bytes in the string (which is multibyte).
If negative, the string is unibyte:
-1 for data normally allocated
-2 for data in rodata (C string constants)
-3 for data that must be immovable (used for bytecode) */
ptrdiff_t size_byte;
Try this:
diff --git a/src/lisp.h b/src/lisp.h
index 1276285e2f2..80bbb047824 100644
--- a/src/lisp.h
+++ b/src/lisp.h
@@ -1685,6 +1685,8 @@ SREF (Lisp_Object string, ptrdiff_t index)
INLINE void
SSET (Lisp_Object string, ptrdiff_t index, unsigned char new)
{
+ if (XSTRING (string)->u.s.size_byte == -2)
+ Fsignal (Qsetting_constant, string);
SDATA (string)[index] = new;
}
INLINE ptrdiff_t
Robert
--
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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Not to mention the added complexity in the code. > > One could check if the string is located in read-only memory. Or one > could add a flag bit to the string data structure (and possibly to other > data structures too). Freezing data structures such that they become > read-only is a generally useful feature. There won't be any performance > overhead of the check since a branch not taken is fast thanks to the > branch predictor. Note also that in-place modification of strings is arbitrarily costly, cf. (aset "ascii" 0 ?=F0=9F=98=BC). Not to mention that it's rarely a good= or necessary move to make, as far as programming style is concerned.
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 11:10:10 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 06:10:10 2023 Received: from localhost ([127.0.0.1]:53799 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1paadW-0003NL-KN for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:10:10 -0500 Received: from server.qxqx.de ([178.63.65.180]:55721 helo=mail.qxqx.de) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1paadU-0003N4-SJ for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 06:10:09 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=RW9wvMKL6iZ555hLtij0V/3l014uS/3myP1ojNmJoG0=; b=w5ZQ0W0NwCvKokqpYNaoSU4Qe/ VXcdATlUZUTPzGLz7idjBKHgBRPkL3TsNe/O7pUav2HHfCDNWx1hPOZvKf1/RD7XVmrg7UugPQw4C vhxDZwFXL8vJdKDtIj/N0xdSdGwYvN2T63mKZpMyteBMlaVnXBAqwsQD+ABuPLrkP18M=; Message-ID: <43460d2c-ba80-0f2f-656c-ef0aca5667b5@HIDDEN> Date: Fri, 10 Mar 2023 12:09:59 +0100 MIME-Version: 1.0 Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name To: Gregory Heytings <gregory@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> <16ecbe9ea85b22d008fd@HIDDEN> Content-Language: en-US From: Daniel Mendler <mail@HIDDEN> In-Reply-To: <16ecbe9ea85b22d008fd@HIDDEN> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) On 3/10/23 11:59, Gregory Heytings wrote: > Is "symbol-name" a function that is used in performance-critical code? > And did you actually measure that performance overhead before concluding > that it it "unacceptably large"? According to my measurements, creating a > string from a symbol name costs about 100 CPU cycles. Yes, of course, for example completion. It would add cost all over the place in many packages. Also note the added GC pressure. It is not a good idea to change symbol-name now to allocate strings. >> Raising an exception upon modification would be the best approach. >> > > That would also come with a performance overhead, as there is currently no > way to distinguist strings that are used for symbol names from other > strings. Not to mention the added complexity in the code. One could check if the string is located in read-only memory. Or one could add a flag bit to the string data structure (and possibly to other data structures too). Freezing data structures such that they become read-only is a generally useful feature. There won't be any performance overhead of the check since a branch not taken is fast thanks to the branch predictor. Daniel
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 10:59:08 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 05:59:08 2023 Received: from localhost ([127.0.0.1]:53795 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1paaSp-00036A-Pf for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 05:59:08 -0500 Received: from heytings.org ([95.142.160.155]:33946) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <gregory@HIDDEN>) id 1paaSm-000360-PU for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 05:59:05 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=heytings.org; s=20220101; t=1678445943; bh=eKzxqHXdVyOcXkCF8K+BvWA9bjF5g82NavgfphwU7ZM=; h=Date:From:To:cc:Subject:In-Reply-To:Message-ID:References:From; b=b1HzvHq76K+xZDQJc9x3PLGe4i99zL56w5wuUpa1HKLIc5le25cg1d5221QNPo/JB sRvXv7PChZE6pcy0vBZaSkj/q6Sm2Yoz+eUqSoZO6wkVGWLKC/4hRGkGT4CTDK3nGI s/sWowgS9VqFS8+ZnIW3kWHEFj0OpIbO1MbkOt9Yb5zBUjvisIxSs7ma6tH1p2nfzE BQXF80aCHrdjWE6ng7y5E4iTi7UNpdDsFP02/3t4Voao4ETHH5y0AEuwaY6ZFsNjV1 y6YxQaiEBLnvcErwDu0oU58isy5VT4DH1JG2825fBNAkz6JLVkbP6um2RV2M6VrIsq e5f/+RnwxWMgA== Date: Fri, 10 Mar 2023 10:59:03 +0000 From: Gregory Heytings <gregory@HIDDEN> To: Daniel Mendler <mail@HIDDEN> Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name In-Reply-To: <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> Message-ID: <16ecbe9ea85b22d008fd@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <16ecbe9ea8ba9d39d058@HIDDEN> <a6b6eff0-1aa7-d0e7-3cd9-cc87ae76c421@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset=us-ascii X-Spam-Score: -0.0 (/) X-Debbugs-Envelope-To: 62009 Cc: Philip Kaludercic <philipk@HIDDEN>, michael_heerdegen@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org, Eli Zaretskii <eliz@HIDDEN>, Augusto Stoffel <arstoffel@HIDDEN> X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -1.0 (-) > > Creating a string is not a good idea since it will lead to an > unacceptably large performance overhead. > Is "symbol-name" a function that is used in performance-critical code? And did you actually measure that performance overhead before concluding that it it "unacceptably large"? According to my measurements, creating a string from a symbol name costs about 100 CPU cycles. > > Raising an exception upon modification would be the best approach. > That would also come with a performance overhead, as there is currently no way to distinguist strings that are used for symbol names from other strings. Not to mention the added complexity in the code.
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Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
To: Gregory Heytings <gregory@HIDDEN>, Eli Zaretskii <eliz@HIDDEN>
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On 3/10/23 10:40, Gregory Heytings wrote:
> Instead of raising a signal, I suggest:
>
> diff --git a/src/data.c b/src/data.c
> index 0f1d881e00b..76867d6787e 100644
> --- a/src/data.c
> +++ b/src/data.c
> @@ -780,7 +780,7 @@ DEFUN ("symbol-name", Fsymbol_name, Ssymbol_name, 1,
> 1, 0,
>
> CHECK_SYMBOL (symbol);
> name = SYMBOL_NAME (symbol);
> - return name;
> + return build_string (SSDATA (name));
> }
>
> DEFUN ("bare-symbol", Fbare_symbol, Sbare_symbol, 1, 1, 0,
Creating a string is not a good idea since it will lead to an
unacceptably large performance overhead. Raising an exception upon
modification would be the best approach.
Daniel
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Date: Fri, 10 Mar 2023 09:40:31 +0000
From: Gregory Heytings <gregory@HIDDEN>
To: Eli Zaretskii <eliz@HIDDEN>
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
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>>> AFAICT, they _are_ frozen. These names are in read-only memory, where
>>> you cannot write. That's why Emacs crashes, AFAIU: the code is trying
>>> to write to protected memory.
>>>
>>> Just don't do that, cause it's gonna hurt...
>>
>> Is it not possible to detect this before the illegal memory access, and
>> raise a signal in Emacs Lisp?
>
> It won't be easy, if at all possible. And I'm not sure we even want to
> do that. What would be the purpose of supporting such a use of Emacs?
>
Instead of raising a signal, I suggest:
diff --git a/src/data.c b/src/data.c
index 0f1d881e00b..76867d6787e 100644
--- a/src/data.c
+++ b/src/data.c
@@ -780,7 +780,7 @@ DEFUN ("symbol-name", Fsymbol_name, Ssymbol_name, 1,
1, 0,
CHECK_SYMBOL (symbol);
name = SYMBOL_NAME (symbol);
- return name;
+ return build_string (SSDATA (name));
}
DEFUN ("bare-symbol", Fbare_symbol, Sbare_symbol, 1, 1, 0,
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 08:47:44 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 03:47:44 2023 Received: from localhost ([127.0.0.1]:53663 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1paYPg-0007tv-Iu for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 03:47:44 -0500 Received: from mail-ed1-f49.google.com ([209.85.208.49]:33448) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <arstoffel@HIDDEN>) id 1paYPe-0007tK-1h for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 03:47:43 -0500 Received: by mail-ed1-f49.google.com with SMTP id a25so17665216edb.0 for <62009 <at> debbugs.gnu.org>; Fri, 10 Mar 2023 00:47:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; t=1678438056; h=mime-version:user-agent:message-id:date:references:in-reply-to :subject:cc:to:from:from:to:cc:subject:date:message-id:reply-to; bh=V2CK2T8vr9fmbaecarxwVXiXP+tdt+JZNEKzEMoTLBE=; b=TV73SV9hDzHCqPHmGBjevJqEBc1SdwoRLA4cjNbg5LcKSyA51qdRnhNsAPtbm08w6r +xU7Tr8rejs+vSxzxCMhKlAnk4vWXtU5S5hf9LlEqGJ53UkUpCTKdeBWeVaNTHCKiXX/ U9c9fgSOZK1EMcM5vlX8WgPaU7Wj3hPFpgNld9qlLPEzQoAjL5Aa0CkT/mM8E9JrrPrK vfMK0HRjZWTyWBZnRj/w2hJE2ZXvCTQT9PdHPmAy8AkpTvqo7JA9q+SnVwwbsfsWMzHb g2xEkfsRIR/h1XkPTSfOw6uwUWsJG/b6azjxemXvDbNqa/rWToAeKzGPVXed4jTXM4sP P11w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; t=1678438056; h=mime-version:user-agent:message-id:date:references:in-reply-to :subject:cc:to:from:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=V2CK2T8vr9fmbaecarxwVXiXP+tdt+JZNEKzEMoTLBE=; b=jsm3MEX3n55DjuGH+ZERox9u8fXRqq5jBHv+JEvNLG7hjnwPdN1bWi7Di+eTp6gl5y YwJsz4T9jgilkSG9aeiUgODr9Q/QbD52chsT8PDGsqIYzemqu1M8rTDu8i9+fHSX9PN8 2g6t6iVY70c0cedGc7zHEyF9pbTDUq9CKILQPK7uCa9Rn6iubLUjWkGDJO56650TXvb8 af7LfCd6a726KAWC3F98uOjDQJ2+pLXPTD5HAIv6Xtd2lOuT5Ro2qEtjuvO0YyHJUUn5 tSGVVp/CpSgra1s2q+Mfak9Q3xqG0YQFV1LBv9GhDVoVjpjBLYviJ/1xcjxBS6slmNuZ 5RsA== X-Gm-Message-State: AO0yUKVRY6sBz6wZrrWtoahk1+8UgKRqSbNg9ipjd6Y39/PWQHVIlnjI po0iLIQZldt/ly8LvE9zvG2hzZ/Mexw14A== X-Google-Smtp-Source: AK7set/zTiOq1N8sGBtPTYuz0yJqs1IH0aW1lQWl7Kon/cPJXU0tWsFvAGY35yiQZEj8CT5kUORg5Q== X-Received: by 2002:a17:906:6b1a:b0:8b1:7ab0:a462 with SMTP id q26-20020a1709066b1a00b008b17ab0a462mr23371597ejr.7.1678438055844; Fri, 10 Mar 2023 00:47:35 -0800 (PST) Received: from ars3 ([2a02:8109:8ac0:56d0::8b3a]) by smtp.gmail.com with ESMTPSA id m21-20020a170906161500b008b17662e1f7sm697049ejd.53.2023.03.10.00.47.35 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 10 Mar 2023 00:47:35 -0800 (PST) From: Augusto Stoffel <arstoffel@HIDDEN> To: Eli Zaretskii <eliz@HIDDEN> Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name In-Reply-To: <87ilf9571k.fsf@HIDDEN> (Augusto Stoffel's message of "Fri, 10 Mar 2023 09:45:11 +0100") References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> <83a60l13p2.fsf@HIDDEN> <87ilf9571k.fsf@HIDDEN> Date: Fri, 10 Mar 2023 09:47:33 +0100 Message-ID: <87edpx56xm.fsf@HIDDEN> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: 0.0 (/) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, mail@HIDDEN, Philip Kaludercic <philipk@HIDDEN>, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -1.0 (-) On Fri, 10 Mar 2023 at 09:45, Augusto Stoffel wrote: > On Fri, 10 Mar 2023 at 09:11, Eli Zaretskii wrote: > >>> Is it not possible to detect this before the illegal memory access, and >>> raise a signal in Emacs Lisp? >> >> It won't be easy, if at all possible. And I'm not sure we even want >> to do that. What would be the purpose of supporting such a use of >> Emacs? > > What is the purpose of supporting mutation of symbol names in general? > > (aset (symbol-name 'find-file) 1 ?o) > (fboundp 'find-file) > => nil > > This one doesn't crash Emacs, but wreaks havoc, maybe in even worse > ways. (To clarify, I think this of course should raise a signal.)
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 10 Mar 2023 07:11:32 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Fri Mar 10 02:11:32 2023 Received: from localhost ([127.0.0.1]:53532 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1paWuZ-0005Uw-Nw for submit <at> debbugs.gnu.org; Fri, 10 Mar 2023 02:11:32 -0500 Received: from eggs.gnu.org ([209.51.188.92]:54788) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1paWuX-0005Ui-UK for 62009 <at> debbugs.gnu.org; Fri, 10 Mar 2023 02:11:30 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1paWuR-00019l-Rz; Fri, 10 Mar 2023 02:11:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=7HWhfYNmGeEBxXDOcUmUmtdTUempUT7fQh5EkF5zKiE=; b=aixqg3dwvGd6 akFUX3zMFFTJpdcXFEUiAxzZx7tT/QkdwzQr0Xs5ksMFAzQfBlR++U7YLgr6yUdYdPXhEULYr9jIf V457EXMxZoijNWCACROpAVwDFnS736Ynq1gJyL6u3uXGy4w7D5E9+XPfrN7b7WY0bKANwIN/LdPQF JBjI7UygLovNSg/l9nD0GEXSHB5f2Pj40WS/AIsrKMaGbhzG0uo8IGt+18FIVMC82iaYatXZ+YvGm rFFPF3iVGkshDpp9QncHqHnDNnTiZXXXROPgVJwQDX2xDSc46GcowPgHZwRqNZ/5ClIyPEPk+8uhr 0S/BYyqdQLjQ4LGPwea0xQ==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1paWuR-0000g2-6D; Fri, 10 Mar 2023 02:11:23 -0500 Date: Fri, 10 Mar 2023 09:11:05 +0200 Message-Id: <83a60l13p2.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Philip Kaludercic <philipk@HIDDEN> In-Reply-To: <87v8j9zl3i.fsf@HIDDEN> (message from Philip Kaludercic on Thu, 09 Mar 2023 21:11:13 +0000) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> <87v8j9zl3i.fsf@HIDDEN> X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, mail@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > From: Philip Kaludercic <philipk@HIDDEN> > Cc: Daniel Mendler <mail@HIDDEN>, michael_heerdegen@HIDDEN, > monnier@HIDDEN, 62009 <at> debbugs.gnu.org > Date: Thu, 09 Mar 2023 21:11:13 +0000 > > > AFAICT, they _are_ frozen. These names are in read-only memory, where > > you cannot write. That's why Emacs crashes, AFAIU: the code is trying > > to write to protected memory. > > > > Just don't do that, cause it's gonna hurt... > > Is it not possible to detect this before the illegal memory access, and > raise a signal in Emacs Lisp? It won't be easy, if at all possible. And I'm not sure we even want to do that. What would be the purpose of supporting such a use of Emacs?
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 9 Mar 2023 21:11:24 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Thu Mar 09 16:11:24 2023 Received: from localhost ([127.0.0.1]:53207 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1paNXn-0005dY-Ox for submit <at> debbugs.gnu.org; Thu, 09 Mar 2023 16:11:24 -0500 Received: from mout01.posteo.de ([185.67.36.65]:54767) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <philipk@HIDDEN>) id 1paNXl-0005dK-1t for 62009 <at> debbugs.gnu.org; Thu, 09 Mar 2023 16:11:21 -0500 Received: from submission (posteo.de [185.67.36.169]) by mout01.posteo.de (Postfix) with ESMTPS id 898C42401F5 for <62009 <at> debbugs.gnu.org>; Thu, 9 Mar 2023 22:11:15 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=posteo.net; s=2017; t=1678396275; bh=OTRXVVUkSa3AyZEiVnO3ik8nOJh+ywgiJbLz8SgyTqY=; h=From:To:Cc:Subject:Date:From; b=pjCnhRFJ/bL4VxXZ5V22MCpNwo/GLpNvG8CKJm5OaQsr/SoBWLaKdagOfTW+7MEEk ZadNFSlHTCbs3xyA3pLxYnemxbH8/hrC/Zm+6bIvqM3GTJp6Y52mhruQrbgHFMxhMw YGcgUa4mENDspBNAjSfzHiLJjk6FLFzlqxcSTPMg6/CKs8CM8toTfo1UIn3lkyj24S tdLQXrznV114aETgkBFtvRo7hkXLDB3TZUxidcoQYkm7WiJa2i0TqJBAdeZ06t1FX+ 7WI1swm2MXKDaFw+TB7z5NNrSvf7lIIeiPVMppt3e4Cp1FgbluxFD5P5T2Jv0xDhY2 s9NwZApDJsJAA== Received: from customer (localhost [127.0.0.1]) by submission (posteo.de) with ESMTPSA id 4PXhgP67xKz9rxQ; Thu, 9 Mar 2023 22:11:13 +0100 (CET) From: Philip Kaludercic <philipk@HIDDEN> To: Eli Zaretskii <eliz@HIDDEN> Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name In-Reply-To: <83bkl45ul4.fsf@HIDDEN> (Eli Zaretskii's message of "Tue, 07 Mar 2023 19:39:51 +0200") References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> <83bkl45ul4.fsf@HIDDEN> Date: Thu, 09 Mar 2023 21:11:13 +0000 Message-ID: <87v8j9zl3i.fsf@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, Daniel Mendler <mail@HIDDEN>, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) Eli Zaretskii <eliz@HIDDEN> writes: >> Cc: Stefan Monnier <monnier@HIDDEN>, 62009 <at> debbugs.gnu.org >> Date: Tue, 7 Mar 2023 18:08:43 +0100 >> From: Daniel Mendler <mail@HIDDEN> >> >> On 3/7/23 16:45, Michael Heerdegen wrote: >> > Daniel Mendler <mail@HIDDEN> writes: >> > >> >> Execute the following in the scratch buffer: >> >> >> >> (setf (aref (symbol-name 'car) 1) ?o) >> >> >> >> Emacs crashes with a segmentation fault. Is this a well-known issue? I >> >> could reproduce the problem on Emacs 27 and 29. Should there be some >> >> mechanism to protect the strings of symbols? >> > >> > Maybe the outcome was something like that we can't protect everybody in >> > every case from shooting in the own foot, I don't recall. >> >> Maybe it would be possible to introduce a flag which marks strings as >> "frozen"? Then we could ensure that no mutations of such frozen string >> happen. > > AFAICT, they _are_ frozen. These names are in read-only memory, where > you cannot write. That's why Emacs crashes, AFAIU: the code is trying > to write to protected memory. > > Just don't do that, cause it's gonna hurt... Is it not possible to detect this before the illegal memory access, and raise a signal in Emacs Lisp? -- Philip Kaludercic
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 7 Mar 2023 17:40:05 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Tue Mar 07 12:40:05 2023 Received: from localhost ([127.0.0.1]:47134 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pZbID-0004Zr-Dv for submit <at> debbugs.gnu.org; Tue, 07 Mar 2023 12:40:05 -0500 Received: from eggs.gnu.org ([209.51.188.92]:51206) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <eliz@HIDDEN>) id 1pZbIB-0004ZF-Sm for 62009 <at> debbugs.gnu.org; Tue, 07 Mar 2023 12:40:04 -0500 Received: from fencepost.gnu.org ([2001:470:142:3::e]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pZbI4-0004FP-NW; Tue, 07 Mar 2023 12:39:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=gnu.org; s=fencepost-gnu-org; h=References:Subject:In-Reply-To:To:From:Date: mime-version; bh=b+P/SDT7Oa+qFe0kRCQggr+uvA4l/Dzh2CG3WUqXEPs=; b=bIB8/Z8AADpW LPmBQGPqGEi3jK6PKVOWG/2p6ZSs6DiEi2jwFQyvldWG9fsnuVNQknkWNPI+zMoskjyFiNBXhXIHF acHRiWZgxX7d3S39H3Z5uwBW/bzLtJozuQLXbHmxOYnF579XUQOUNLwlVmdQcKwWCa9zjbL89BH3i OZmSKe3NkH5P2rq6Vix0Sr8Iw3o9V7+7Z7ux94wuyjk98a0bpn7vBYapn7FbpK2VE7NeUgzC3uaCJ P+Z/aAHIefJ5nIh97NEcwpIwh3MyQ67e9yUztpSWP+0+a1uW5BWjeeHsUoByRI6otxEzjkpOXSBXe PXULhRcvsv/oHdOMJFVnAw==; Received: from [87.69.77.57] (helo=home-c4e4a596f7) by fencepost.gnu.org with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <eliz@HIDDEN>) id 1pZbI4-0006Ep-2d; Tue, 07 Mar 2023 12:39:56 -0500 Date: Tue, 07 Mar 2023 19:39:51 +0200 Message-Id: <83bkl45ul4.fsf@HIDDEN> From: Eli Zaretskii <eliz@HIDDEN> To: Daniel Mendler <mail@HIDDEN> In-Reply-To: <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> (message from Daniel Mendler on Tue, 7 Mar 2023 18:08:43 +0100) Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: michael_heerdegen@HIDDEN, monnier@HIDDEN, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) > Cc: Stefan Monnier <monnier@HIDDEN>, 62009 <at> debbugs.gnu.org > Date: Tue, 7 Mar 2023 18:08:43 +0100 > From: Daniel Mendler <mail@HIDDEN> > > On 3/7/23 16:45, Michael Heerdegen wrote: > > Daniel Mendler <mail@HIDDEN> writes: > > > >> Execute the following in the scratch buffer: > >> > >> (setf (aref (symbol-name 'car) 1) ?o) > >> > >> Emacs crashes with a segmentation fault. Is this a well-known issue? I > >> could reproduce the problem on Emacs 27 and 29. Should there be some > >> mechanism to protect the strings of symbols? > > > > Maybe the outcome was something like that we can't protect everybody in > > every case from shooting in the own foot, I don't recall. > > Maybe it would be possible to introduce a flag which marks strings as > "frozen"? Then we could ensure that no mutations of such frozen string > happen. AFAICT, they _are_ frozen. These names are in read-only memory, where you cannot write. That's why Emacs crashes, AFAIU: the code is trying to write to protected memory. Just don't do that, cause it's gonna hurt...
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at 62009) by debbugs.gnu.org; 7 Mar 2023 17:08:56 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Tue Mar 07 12:08:55 2023 Received: from localhost ([127.0.0.1]:47103 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pZao3-0003oZ-K1 for submit <at> debbugs.gnu.org; Tue, 07 Mar 2023 12:08:55 -0500 Received: from server.qxqx.de ([178.63.65.180]:39263 helo=mail.qxqx.de) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1pZao1-0003oJ-46 for 62009 <at> debbugs.gnu.org; Tue, 07 Mar 2023 12:08:53 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Transfer-Encoding:Content-Type:In-Reply-To:From: References:Cc:To:Subject:MIME-Version:Date:Message-ID:Sender:Reply-To: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=qCoOtqwmp4RuJYbRhDgajB3nwcD4vQq3RMKaoiSWQNw=; b=e7yF3kPhfJB1nYcsg8jYncG4bY G1n02y6Uqu1lS2tgQss19rzedJEYHsGX3dBsh2yFMEHtXD0FtxWd/UsPNBIdR7XT8XXlCxNc8g5Zz igZeCdk+KLHiPcVRT/bOYu74SX/zop6rC9e4oD6JohhYL6qaG8L/dgboQHwvLpPLZlr8=; Message-ID: <9fcf05e8-506c-6566-e214-2ecf3194b85e@HIDDEN> Date: Tue, 7 Mar 2023 18:08:43 +0100 MIME-Version: 1.0 Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name To: Michael Heerdegen <michael_heerdegen@HIDDEN> References: <87o7p5of4n.fsf@HIDDEN> <871qm01s6n.fsf@HIDDEN> Content-Language: en-US From: Daniel Mendler <mail@HIDDEN> In-Reply-To: <871qm01s6n.fsf@HIDDEN> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Spam-Score: -2.3 (--) X-Debbugs-Envelope-To: 62009 Cc: Stefan Monnier <monnier@HIDDEN>, 62009 <at> debbugs.gnu.org X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -3.3 (---) On 3/7/23 16:45, Michael Heerdegen wrote: > Daniel Mendler <mail@HIDDEN> writes: > >> Execute the following in the scratch buffer: >> >> (setf (aref (symbol-name 'car) 1) ?o) >> >> Emacs crashes with a segmentation fault. Is this a well-known issue? I >> could reproduce the problem on Emacs 27 and 29. Should there be some >> mechanism to protect the strings of symbols? > > Maybe the outcome was something like that we can't protect everybody in > every case from shooting in the own foot, I don't recall. Maybe it would be possible to introduce a flag which marks strings as "frozen"? Then we could ensure that no mutations of such frozen string happen. Freezing strings (vectors or pairs) may be generally useful beyond preventing such issues. Daniel
bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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From: Ruijie Yu <ruijie@HIDDEN>
To: Daniel Mendler <mail@HIDDEN>
Subject: Re: bug#62009: 29.0.60; Emacs crashes on setf symbol-name
Date: Tue, 07 Mar 2023 12:40:06 +0800
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Content preview: Daniel Mendler <mail@HIDDEN> writes: > Execute
the following in the scratch buffer: > > (setf (aref (symbol-name 'car) 1)
?o) > > Emacs crashes with a segmentation fault. Is this a well-known issue?
I > could reproduce the problem on Ema [...]
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Content preview: Daniel Mendler <mail@HIDDEN> writes: > Execute
the following in the scratch buffer: > > (setf (aref (symbol-name 'car) 1)
?o) > > Emacs crashes with a segmentation fault. Is this a well-known issue?
I > could reproduce the problem on Ema [...]
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Content-Type: text/plain
Daniel Mendler <mail@HIDDEN> writes:
> Execute the following in the scratch buffer:
>
> (setf (aref (symbol-name 'car) 1) ?o)
>
> Emacs crashes with a segmentation fault. Is this a well-known issue? I
> could reproduce the problem on Emacs 27 and 29. Should there be some
> mechanism to protect the strings of symbols?
>
> I found the snippet on reddit:
> https://old.reddit.com/r/emacs/comments/11ix6yu/ive_found_what_ive_been_looking_for/jb4ah5v/
Can't access reddit, but can reproduce in recent master (6fb8a4dff7ef).
To test, first put this file under emacs.git/src/:
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment; filename=test.el
(defun foo (symbol)
(message "[1] %S" (symbol-name symbol))
(setf (aref (symbol-name symbol) 1) ?x)
(message "[2] %S" (symbol-name symbol)))
--=-=-=
Content-Type: text/plain
$ make; cd src
Then do the following for each symbol:
- setf
- find-file
- with-current-buffer
- buffer-file-name
$ ./emacs -Q -batch -l test.el -eval '(foo (quote setf))'
[1] "setf"
[2] "sxtf"
$ ./emacs -Q -batch -l test.el -eval '(foo (quote find-file))'
[1] "find-file"
[2] "fxnd-file"
And these below below: aref, null, car, cdr, save-current-buffer
$ ./emacs -Q -batch -l test.el -eval '(foo (quote aref))'
[1] "aref"
Fatal error 11: Segmentation fault
Backtrace:
...
My observation is that symbols "introduced" via C defuns and defmacros
exhibit this problem, whereas those introduced via Elisp defuns and
defmacros do not. No symbols introduced via defvars exhibit this
problem, as shown above with buffer-file-name.
Seeing that it is a segfault, maybe the setf is trying to modify
readonly memory produced by the C defuns and defmacros? If that is the
case, *if* we allow such modifications, we should make the memory
readwrite; *otherwise* maybe we should no-op, warn, or err in setf and
friends when we see readonly memory blocks?
With this collection of GDB commands:
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment; filename=debug.gdb
set debuginfod enabled off
run
bt
exit
--=-=-=
Content-Type: text/plain
And this GDB command line option:
$ gdb -x debug.gdb --batch --args ./emacs -Q -batch -l ../test.el -eval '(foo (quote car))' > car.backtrace
I get the backtrace (attached below) for setf + symbol-name + 'car as
reported by OP.
--=-=-=
Content-Type: text/plain
Content-Disposition: attachment; filename=car.backtrace
SIGINT is used by the debugger.
Are you sure you want to change it? (y or n) [answered Y; input not from terminal]
DISPLAY = :0
TERM = xterm-256color
Breakpoint 1 at 0x4e2ab: file emacs.c, line 426.
Breakpoint 2 at 0x142970: file xterm.c, line 26474.
[Thread debugging using libthread_db enabled]
Using host libthread_db library "/usr/lib/libthread_db.so.1".
Program received signal SIGSEGV, Segmentation fault.
Faset (array=XIL(0x7ffff1d10adc), idx=make_fixnum(1), newelt=make_fixnum(120)) at /opt/src/emacs/base/62009-setf-symbol-name/src/lisp.h:1671
1671 return XSTRING (string)->u.s.data;
#0 Faset (array=XIL(0x7ffff1d10adc), idx=make_fixnum(1), newelt=make_fixnum(120)) at /opt/src/emacs/base/62009-setf-symbol-name/src/lisp.h:1671
#1 0x000055555576f431 in eval_sub (form=<optimized out>) at eval.c:2506
#2 0x000055555577132d in Fprogn (body=XIL(0)) at eval.c:436
#3 FletX (args=<optimized out>) at eval.c:958
#4 0x000055555576f198 in eval_sub (form=<optimized out>) at eval.c:2451
#5 0x00005555557701ed in Fprogn (body=XIL(0x7ffff24d25d3)) at eval.c:436
#6 funcall_lambda (fun=<optimized out>, fun@entry=XIL(0x7ffff24d5b13), nargs=nargs@entry=1, arg_vector=arg_vector@entry=0x7fffffffd9e0) at eval.c:3235
#7 0x000055555577095c in apply_lambda (fun=fun@entry=XIL(0x7ffff24d5b13), args=<optimized out>, count=count@entry=...) at eval.c:3105
#8 0x000055555576eea6 in eval_sub (form=form@entry=XIL(0x7ffff24d5cf3)) at eval.c:2590
#9 0x0000555555771a8f in Feval (form=XIL(0x7ffff24d5cf3), lexical=<optimized out>) at eval.c:2363
#10 0x00005555557b5882 in exec_byte_code (fun=<optimized out>, args_template=<optimized out>, nargs=<optimized out>, args=<optimized out>) at bytecode.c:809
#11 0x000055555577095c in apply_lambda (fun=fun@entry=XIL(0x7ffff19dc085), args=<optimized out>, count=count@entry=...) at eval.c:3105
#12 0x000055555576eea6 in eval_sub (form=form@entry=XIL(0x7ffff1e13773)) at eval.c:2590
#13 0x0000555555771a8f in Feval (form=XIL(0x7ffff1e13773), lexical=<optimized out>) at eval.c:2363
#14 0x0000555555769cf7 in internal_condition_case (bfun=bfun@entry=0x5555556da3b0 <top_level_2>, handlers=handlers@entry=XIL(0x90), hfun=hfun@entry=0x5555556e1990 <cmd_error>) at eval.c:1474
#15 0x00005555556dad36 in top_level_1 (ignore=ignore@entry=XIL(0)) at keyboard.c:1141
#16 0x0000555555769c51 in internal_catch (tag=tag@entry=XIL(0x103e0), func=func@entry=0x5555556dad10 <top_level_1>, arg=arg@entry=XIL(0)) at eval.c:1197
#17 0x00005555556da32f in command_loop () at keyboard.c:1101
#18 0x00005555556e1512 in recursive_edit_1 () at keyboard.c:711
#19 0x00005555556e18a0 in Frecursive_edit () at keyboard.c:794
#20 0x00005555555ab49f in main (argc=7, argv=0x7fffffffe0a8) at emacs.c:2530
Lisp Backtrace:
"aset" (0xffffd790)
"let*" (0xffffd8c0)
"foo" (0xffffd9e0)
"eval" (0xf05ff1c0)
"command-line-1" (0xf05ff0b8)
"command-line" (0xf05ff040)
"normal-top-level" (0xffffdbd0)
A debugging session is active.
Inferior 1 [process 1106482] will be killed.
Quit anyway? (y or n) [answered Y; input not from terminal]
--=-=-=
Content-Type: text/plain
HTH.
--
Best,
RY
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bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
Full text available.Received: (at submit) by debbugs.gnu.org; 6 Mar 2023 19:27:03 +0000 From debbugs-submit-bounces <at> debbugs.gnu.org Mon Mar 06 14:27:03 2023 Received: from localhost ([127.0.0.1]:43670 helo=debbugs.gnu.org) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <debbugs-submit-bounces <at> debbugs.gnu.org>) id 1pZGUB-0001LP-AK for submit <at> debbugs.gnu.org; Mon, 06 Mar 2023 14:27:03 -0500 Received: from lists.gnu.org ([209.51.188.17]:57792) by debbugs.gnu.org with esmtp (Exim 4.84_2) (envelope-from <mail@HIDDEN>) id 1pZGU9-0001Kz-3u for submit <at> debbugs.gnu.org; Mon, 06 Mar 2023 14:27:01 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <mail@HIDDEN>) id 1pZGU6-0003VI-Oc for bug-gnu-emacs@HIDDEN; Mon, 06 Mar 2023 14:26:59 -0500 Received: from server.qxqx.de ([2a01:4f8:121:346::180] helo=mail.qxqx.de) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from <mail@HIDDEN>) id 1pZGU4-0005zJ-5F for bug-gnu-emacs@HIDDEN; Mon, 06 Mar 2023 14:26:58 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=qxqx.de; s=mail1392553390; h=Content-Type:MIME-Version:Message-ID:Date:Subject:To:From :Sender:Reply-To:Cc:Content-Transfer-Encoding:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: In-Reply-To:References:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=ApFsH2+SjZZO7stR2Bs4xTFPy4fywFG86CO9KuUMmIY=; b=oWwG+rfF+FjWqCAsmvXFmwptiO M/gnElyVLWsAJwf68WiECN7nvmXk0DYmiAP1p1Hqr7oEV1/ykIOkrlBUG54JesoLBj+NLUflN20HA DmiLD3w4Gj8MUhhC72YU/4LpwgkMp6s51x1gUYMxDGS1MLQWRwFEVBzuU1daKwz2oKsY=; From: Daniel Mendler <mail@HIDDEN> To: bug-gnu-emacs@HIDDEN Subject: 29.0.60; Emacs crashes on setf symbol-name Date: Mon, 06 Mar 2023 20:26:32 +0100 Message-ID: <87o7p5of4n.fsf@HIDDEN> MIME-Version: 1.0 Content-Type: text/plain Received-SPF: pass client-ip=2a01:4f8:121:346::180; envelope-from=mail@HIDDEN; helo=mail.qxqx.de X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-Spam-Score: -1.4 (-) X-Debbugs-Envelope-To: submit X-BeenThere: debbugs-submit <at> debbugs.gnu.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: <debbugs-submit.debbugs.gnu.org> List-Unsubscribe: <https://debbugs.gnu.org/cgi-bin/mailman/options/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=unsubscribe> List-Archive: <https://debbugs.gnu.org/cgi-bin/mailman/private/debbugs-submit/> List-Post: <mailto:debbugs-submit <at> debbugs.gnu.org> List-Help: <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=help> List-Subscribe: <https://debbugs.gnu.org/cgi-bin/mailman/listinfo/debbugs-submit>, <mailto:debbugs-submit-request <at> debbugs.gnu.org?subject=subscribe> Errors-To: debbugs-submit-bounces <at> debbugs.gnu.org Sender: "Debbugs-submit" <debbugs-submit-bounces <at> debbugs.gnu.org> X-Spam-Score: -2.4 (--) Execute the following in the scratch buffer: (setf (aref (symbol-name 'car) 1) ?o) Emacs crashes with a segmentation fault. Is this a well-known issue? I could reproduce the problem on Emacs 27 and 29. Should there be some mechanism to protect the strings of symbols? I found the snippet on reddit: https://old.reddit.com/r/emacs/comments/11ix6yu/ive_found_what_ive_been_looking_for/jb4ah5v/
Daniel Mendler <mail@HIDDEN>:bug-gnu-emacs@HIDDEN.
Full text available.bug-gnu-emacs@HIDDEN:bug#62009; Package emacs.
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