GNU bug report logs - #42660
emacs-27.1-rc1 and UBsan findings

Previous Next

Package: emacs;

Reported by: noloader <at> gmail.com

Date: Sat, 1 Aug 2020 20:35:02 UTC

Severity: normal

Done: Paul Eggert <eggert <at> cs.ucla.edu>

Bug is archived. No further changes may be made.

Full log

View this message in rfc822 format

From: Lars Ingebrigtsen <larsi <at> gnus.org>
To: Jeffrey Walton <noloader <at> gmail.com>
Cc: 42660 <at> debbugs.gnu.org
Subject: bug#42660: emacs-27.1-rc1 and UBsan findings
Date: Mon, 10 Aug 2020 12:37:12 +0200

(Please keep the debbugs address in the Cc field.)

Jeffrey Walton <noloader <at> gmail.com> writes:

>> So it's doing a left shift on a too-high number...  which is something
>> that pgg does, but since that's obsolete, do we care?
>
> Integer wrap is well defined. Cast reg[rrr] to an unsigned. If
> reg[rrr] is left as signed, then it overflows (sign change) and
> wanders into undefined behavior and is subject to removal.
>
> Or you can remove the test.

It would obviously be better to fix the undefined behaviour (if the
compiler is correct here?), but as the only thing that seems to tickle
this behaviour is an obsolete package, I'm not sure we care?

But perhaps we do?

The CCL isn't the most popular stuff in Emacs these days...
This bug report was last modified 4 years and 277 days ago.

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.