bug(sort): large --parallel values is accepted, gnu just ignore them

[HackingRepo]

Hi, uutils mainteners

we confirmed the uu sort --parallel 4096, is accepted and that is unrealistic, the gnu just simply ignores the flag because large

relunsec@relunsec:~/software/coreutils/target/release$  ./sort --parallel 4096 /usr/share/dict/words

we confirmed that via using the following

[oech3]

I don't think GNU should ignore it. See https://collinfunk.com/arbitrary-limits-avoided-by-gnu-coreutils

[HackingRepo]

@oech3, it is reproducible

relunsec@relunsec:~/software/coreutils/gnucoreutils_extracted/usr/bin$ touch a
relunsec@relunsec:~/software/coreutils/gnucoreutils_extracted/usr/bin$ ./sort --version
sort (GNU coreutils) 9.11
Copyright (C) 2026 Free Software Foundation, Inc.
License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.
This is free software: you are free to change and redistribute it.
There is NO WARRANTY, to the extent permitted by law.

Written by Mike Haertel and Paul Eggert.
relunsec@relunsec:~/software/coreutils/gnucoreutils_extracted/usr/bin$ ./sort --parallel 4096 a
relunsec@relunsec:~/software/coreutils/gnucoreutils_extracted/usr/bin$ ../../../target/debug/sort --parallel 4096 a

the uu sort hangs forever, while gnu instantly, exit that was the latest version, no longer 9.8 or anything else, it was reproducible fully, uu sort consumed massive cpu and memory

[oech3]

I wanted to say GNU is viorating their policy.

[HackingRepo]

yes, in the case of sort, they do, uu it looks like to me, good maybe an issue with gnu itself, it violates it policy, because accepted arbiratry values whiches correct, gnu is the one wrong

[oech3]

cc @collinfunk

[collinfunk]

I assume uutils is actually creating 4096 threads, which is more expensive than just sorting that file with a single core.

[oech3]

How about sort on server having 4096 physical cores?

[sylvestre]

let's focus on what is currently doable and not on rhetorical issues ? ;)

[oech3]

I just don't want to be simply do same things with GNU at here.
If we restrict threads, both of GNU and uutils should fix document of this flag.