ansible/test/integration/targets/fork_safe_stdio/runme.sh

#!/usr/bin/env bash

set -eu

echo "testing for stdio deadlock on forked workers (10s timeout)..."

# Enable a callback that trips deadlocks on forked-child stdout, time out after 10s; forces running
# in a pty, since that tends to be much slower than raw file I/O and thus more likely to trigger the deadlock.
# Redirect stdout to /dev/null since it's full of non-printable garbage we don't want to display unless it failed
ANSIBLE_CALLBACKS_ENABLED=spewstdio SPEWSTDIO_ENABLED=1 python run-with-pty.py ../test_utils/scripts/timeout.py -- 10 ansible-playbook -i hosts -f 5 test.yml > stdout.txt && RC=$? || RC=$?

if [ $RC != 0 ]; then
  echo "failed; likely stdout deadlock. dumping raw output (may be very large)"
  cat stdout.txt
  exit 1
fi

grep -q -e "spewstdio STARTING NONPRINTING SPEW ON BACKGROUND THREAD" stdout.txt || (echo "spewstdio callback was not enabled"; exit 1)

echo "PASS"
Prevent stdio deadlock in forked children (#79522) * background threads writing to stdout/stderr can cause children to deadlock if a thread in the parent holds the internal lock on the BufferedWriter wrapper * prevent writes to std handles during fork by monkeypatching stdout/stderr during display startup to require a mutex lock with fork(); this ensures no background threads can hold the lock during a fork operation * add integration test that fails reliably on Linux without this fix 2 years ago			`#!/usr/bin/env bash`

			`set -eu`

			`echo "testing for stdio deadlock on forked workers (10s timeout)..."`

			`# Enable a callback that trips deadlocks on forked-child stdout, time out after 10s; forces running`
			`# in a pty, since that tends to be much slower than raw file I/O and thus more likely to trigger the deadlock.`
			`# Redirect stdout to /dev/null since it's full of non-printable garbage we don't want to display unless it failed`
Switch from multiprocessing.Queue to SimpleQueue (#80838) 1 year ago			`ANSIBLE_CALLBACKS_ENABLED=spewstdio SPEWSTDIO_ENABLED=1 python run-with-pty.py ../test_utils/scripts/timeout.py -- 10 ansible-playbook -i hosts -f 5 test.yml > stdout.txt && RC=$? \|\| RC=$?`
Prevent stdio deadlock in forked children (#79522) * background threads writing to stdout/stderr can cause children to deadlock if a thread in the parent holds the internal lock on the BufferedWriter wrapper * prevent writes to std handles during fork by monkeypatching stdout/stderr during display startup to require a mutex lock with fork(); this ensures no background threads can hold the lock during a fork operation * add integration test that fails reliably on Linux without this fix 2 years ago
			`if [ $RC != 0 ]; then`
			`echo "failed; likely stdout deadlock. dumping raw output (may be very large)"`
			`cat stdout.txt`
			`exit 1`
			`fi`

			`grep -q -e "spewstdio STARTING NONPRINTING SPEW ON BACKGROUND THREAD" stdout.txt \|\| (echo "spewstdio callback was not enabled"; exit 1)`

			`echo "PASS"`