ocrmypdf/OCRmyPDF · critical · InputFileError

A worker process lost access to an input file

Error message

A worker process lost access to an input file

What it means

This is the semaphore-free executor plugin's (extra_plugins.semfree) copy of the SIGBUS worker handler: it raises InputFileError when a worker process receives SIGBUS, meaning a mapped/open input or temp file vanished or its storage failed mid-run.

Source

Thrown at src/ocrmypdf/extra_plugins/semfree.py:67

    result = auto()  # pylint: disable=invalid-name
    complete = auto()  # pylint: disable=invalid-name


def split_every(n: int, iterable: Iterable) -> Iterator:
    """Split iterable into groups of n.

    >>> list(split_every(4, range(10)))
    [[0, 1, 2], [3, 4, 5], [6, 7, 8], [9]]

    https://stackoverflow.com/a/22919323
    """
    iterator = iter(iterable)
    return takewhile(bool, (list(islice(iterator, n)) for _ in repeat(None)))


def process_sigbus(*args):
    """Handle SIGBUS signal at the worker level."""
    raise InputFileError("A worker process lost access to an input file")


class ConnectionLogHandler(logging.handlers.QueueHandler):
    """Handler used by child processes to forward log messages to parent."""

    def __init__(self, conn: Connection) -> None:
        """Initialize the handler."""
        # sets the parent's queue to None - parent only touches queue
        # in enqueue() which we override
        super().__init__(None)  # type: ignore
        self.conn = conn

    def enqueue(self, record):
        """Enqueue a log message."""
        self.conn.send(('log', record))


def process_loop(

View on GitHub (pinned to 5074a0b0e1)

Solutions

1. Free space on TMPDIR/output filesystems and retry.
2. Keep inputs on stable local storage and prevent concurrent deletion/cleanup during the job.
3. Set TMPDIR to a disk-backed path with enough room.

import shutil, os
assert shutil.disk_usage(os.environ.get('TMPDIR','/tmp')).free > 1_000_000_000

from ocrmypdf.exceptions import InputFileError
try:
    run_with_semfree(...)
except InputFileError:
    stabilize_storage(); retry_job()

When it happens

Trigger: Using the semfree concurrency plugin when an input/temp file is truncated or deleted during processing, or when the filesystem backing it (disk, tmpfs, network mount) errors.

Common situations: Same as the builtin pool: tmpfs filling up, aggressive tmp cleaners, or unstable network-mounted inputs, plus choosing semfree for very high page counts.

Related errors

• A worker process lost access to an input file
• --redo-ocr (or --mode redo) is not currently compatible with
• Since you specified `--output-type none`, the output file {s
• Input file is an image, but the resolution (DPI) is not cred
• Input file is an image, but has no resolution (DPI) in its m

AI-assisted analysis of ocrmypdf/OCRmyPDF@5074a0b0e1 (2026-08-27). Data as JSON: /api/errors/76f509893f57be7f. Report an issue: GitHub.