On 20/05/2025 16:15, Pádraig Brady wrote:
> Indeed. I introduced this in coreutils 7.2 (2009).
> One can repro on Fedora for e.g. with:
> 
> _POSIX2_VERSION=200809 LC_ALL=C valgrind sort +0.18446744073709551615R poc_input.txt
> ==984625== Memcheck, a memory error detector
> ==984625== Using Valgrind-3.24.0 and LibVEX; rerun with -h for copyright info
> ==984625== Command: sort +0.18446744073709551615R poc_input.txt
> ==984625==
> ==984625== Invalid read of size 1
> 
> Going back to the more verbose code from coreutils 7.1 avoids the issue.
> I'll test a bit more here and post a full patch in a while.

The attached patch addresses the issue here,
and includes a test verified to trigger with ASAN or valgrind available.
I'll push this later.

thanks,
Pádraig