uutils/coreutils · error

Failed to join with the output thread.

Error message

Failed to join with the output thread.

What it means

Error "Failed to join with the output thread." thrown in uutils/coreutils.

Source

Thrown at src/uu/dd/src/dd.rs:1267

                i.discard_cache(read_offset, 0);
            }
            if output_nocache || output_direct {
                o.discard_cache(write_offset.try_into().unwrap(), 0);
            }
            break;
        }
        let Ok(wstat_update) = o.write_blocks(data).map_err(|e| copy_error = Some(e)) else {
            break;
        };

        // Discard the system file cache for the read portion of
        // the input file.
        //
        // TODO Better error handling for overflowing `offset` and `len`.
        let read_len = rstat_update.bytes_total;
        if input_nocache {
            let offset = read_offset;
            let len = read_len;
            i.discard_cache(offset, len);
        }
        read_offset += read_len;

        // Discard the system file cache for the written portion
        // of the output file.
        //
        // TODO Better error handling for overflowing `offset` and `len`.
        let write_len = wstat_update.bytes_total;
        if output_nocache {
            let offset = write_offset.try_into().unwrap();
            let len = write_len.try_into().unwrap();
            o.discard_cache(offset, len);
        }
        write_offset += write_len;

        // Update the read/write stats and inform the progress thread once per second.
        //

View on GitHub (pinned to 9ff4114e82)

Solutions

1. Ensure the output thread has not panicked; check its error before joining.
2. Close the input side properly so the output thread can finish and be joined.

When it happens

Trigger: Occurs when dd cannot join its output thread, meaning the output thread panicked or terminated abnormally.

Common situations: An I/O error or panic inside dd's writer thread, surfacing at join time.

AI-assisted analysis of uutils/coreutils@9ff4114e82 (2026-08-19). Data as JSON: /api/errors/df54f8123e16a053. Report an issue: GitHub.