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From: Lars Ingebrigtsen <larsi@gnus.org>
To: Andy Gaynor <goldipox@mail.com>
Cc: 54501@debbugs.gnu.org, Stefan Monnier <monnier@iro.umontreal.ca>
Subject: bug#54501: Segfault on recursive structure
Date: Tue, 22 Mar 2022 15:44:43 +0100	[thread overview]
Message-ID: <87cziekpwk.fsf@gnus.org> (raw)
In-Reply-To: <trinity-3fb98d93-dfba-4296-8aa2-25b533a96589-1647872762799@3c-app-mailcom-lxa14> (Andy Gaynor's message of "Mon, 21 Mar 2022 15:26:02 +0100")

So this bug report is about two things.  The first is that this reads to
(nil):

#0=#0#

Which seems odd.  Reading #0=#1# signals an error, but it's not
immediately clear to me whether #0=#0# is totally nonsensical or not.
And if not, is (nil) the right result?  Anybody?

The other thing is more serious, and reading the following will segfault
your Emacs, so don't do that:

#0=[#1=(#0# . #1#)]

Now, Emacs segfaults on trying to gc a number of recursive objects
(especially ones that recurse in the `car'), but this seems to actually
segfault in the reader.  Is it obvious to anybody why?

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no






  reply	other threads:[~2022-03-22 14:44 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-21 14:26 bug#54501: 27.2; to be disclosed in private Andy Gaynor
2022-03-22 14:44 ` Lars Ingebrigtsen [this message]
2022-03-22 15:02   ` bug#54501: Segfault on recursive structure Andreas Schwab
2022-03-22 15:04     ` Lars Ingebrigtsen
     [not found]       ` <trinity-1bb5c502-bafe-4a6c-b6be-08a2a1b27232-1648049044877@3c-app-mailcom-lxa04>
2022-03-25 15:34         ` Lars Ingebrigtsen
2022-03-26 15:58 ` Mattias Engdegård
2022-03-26 16:33   ` Lars Ingebrigtsen
     [not found]     ` <8F7060F3-8137-4835-873F-68E3F6B8010D@acm.org>
2022-03-26 17:43       ` Mattias Engdegård
2022-03-26 18:00     ` Eli Zaretskii

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