[Bug 2134389] Re: coreutils-from-uutils performs badly and crashes

[Benjamin Schlechter]

As I'm unable to publish parts of the project I'm working on, I tried to come up with a minimal example.
For comparability (and as I didn't want to risk my currently working setup), I was using docker:
sudo docker run -it --rm ubuntu:24.04 bash
sudo docker run -it --rm ubuntu:25.10 bash

With the following commands in both setups:
apt update
#apt search coreutils-from-uutils
mkdir test && cd test
apt install make vim zstd pv parallel
vim Makefile # for the contents see further down
make clean ; time make -j 1024

Which made me reproduce at least a (smaller) performance hit:
# ubuntu 24.04 docker image with gnu coreutils:
real	0m22.570s
user	2m2.905s
sys	3m42.032s

# Ubuntu 25.10 docker image with coreutils-from-uutils
real	0m32.018s
user	2m57.540s
sys	5m11.862s

The performance loss is therefore likely independent of the stat failure
I've seen. Unfortunately I cannot spent more time right now on it to
also try to reproduce the stat coredump (e.g. by reinstalling coreutils-
from-uutils on my main system and experimenting further with the minimal
example). So I cannot say if the stat coredump has already been fixed in
the meantime.

The Makefile below (partly AI generated) doesn't have any meaning
besides using some of the simpler tools used in the way larger project
I'm working on, calling them in a stress testing approach by interacting
with many files / file handles / pipes at once. Please take note the
Makefile parameter NUM_FILES.

Thank you for taking a look! And sorry if this doesn't help too much,
but maybe it is useful for optimizing performance... Otherwise or in
regard to the stat coredump feel free to close this issue as not
reproducable, as I don't have more time for this right now. Kind
regards.

Makefile:

# Variables
RANDOM_DIR := random_files
COMPRESSED_DIR := compressed_files
NUM_FILES := 200
FILE_SIZE := 10K   # Each random file will be 1KB
RANDOM_FILES := $(addprefix $(RANDOM_DIR)/file,$(addsuffix .bin,$(shell seq 1 $(NUM_FILES))))
COMPRESSED_FILES := $(patsubst $(RANDOM_DIR)/%.bin,$(COMPRESSED_DIR)/%.zst,$(RANDOM_FILES))

SHELL=bash

.PHONY: all randomfiles compress clean

all: compress

# Target to create 1000 random files using dd (with /dev/urandom)
$(RANDOM_DIR)/file%.bin:
	@mkdir -p $(RANDOM_DIR)
	@bash -c "umask 000 ; dd if=/dev/urandom of=$@ bs=$(FILE_SIZE) count=1 status=none"

randomfiles: $(RANDOM_FILES)

# Generic compression target using zstd for each random file
$(COMPRESSED_DIR)/%.zst: $(RANDOM_DIR)/%.bin
	@mkdir -p $(COMPRESSED_DIR)
	echo -e "bash <<'EOF'\n(umask 000; cat $< $(ls -lrt $(RANDOM_DIR) |shuf |tail -5 |grep -oP 'file.*$'|parallel -I{} echo $(RANDOM_DIR)/{}) | pv | zstd -q ) | tee $@ >(( bash -c 'ls -1 $(RANDOM_DIR) | parallel -j32 -I{} stat $(RANDOM_DIR)/{}' > /dev/null && wc -c ) >&2) | sha512sum | awk '{print $$1}' > $@.sha512\nEOF" |bash

compress: $(COMPRESSED_FILES)

clean:
	rm -rf $(RANDOM_DIR) $(COMPRESSED_DIR)

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https://bugs.launchpad.net/bugs/2134389

Title:
  coreutils-from-uutils performs badly and crashes

Status in rust-coreutils package in Ubuntu:
  Opinion

Bug description:
  On Ubuntu 25.10 with the latest updates as of 2025-12-08, I see stat crashing randomly (reported separately over ubuntu's bug reporting tool) without any obvious errors being visible to me as a user except this dmesg entry: coredump: 7808(stat): over core_pipe_limit, skipping core dump
  However make parsing a Makefile is over 100 times slower with the rust coreutils than the gnu ones, so I assume stat crashing in the background has some noticeable performance hit. But I would expect make crashing then too. Therefore I created this issue because I suspect some error codes are not being treated accordingly. Anyway it could be something else wrong with coreutils-from-uutils performance wise as well.

  The only acceptable solution for me was to use the gnu coreutils as a workaround for now.
  sudo apt-get remove coreutils-from-uutils --allow-remove-essential

  I'm concerned the coreutils-from-uutils is not yet production ready.

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