GNU bug report logs - #64316
ASAN failures in dir.c

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Message #19 received at 64316 <at> debbugs.gnu.org (full text, mbox):

From: Paul Eggert <eggert <at> cs.ucla.edu>
To: Gisle Vanem <gvanem <at> yahoo.no>
Cc: 64316 <at> debbugs.gnu.org
Subject: Re: [bug-diffutils] bug#64316: ASAN failures in dir.c
Date: Wed, 28 Jun 2023 15:31:55 -0700

[Message part 1 (text/plain, inline)]

On 2023-06-28 03:32, Gisle Vanem wrote:
> 'PTRDIFF_T_MAX - - 3' folds to '-9223372036854775806'.
> 
> But how can 'linbuf_base' become negative?

Ordinarily it's zero, but it can be negative. It's never positive.

Thanks for the report. I reproduced the signed integer overflow issue 
with -fsanitize=undefined and installed the attached patch to fix it and 
add a regression test (and also a comment about linbuf_base).

Although I don't see how this would fix a "memory exhausted" error, 
please give the latest Git commit a try and see whether it fixes things 
for you.

[0001-diff-fix-xpalloc-related-signed-integer-overflow.patch (text/x-patch, attachment)]

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