## Summary
When `Job.Cancel()` is called on a running `UDisksSpawnedJob` (e.g., disk erase operation), the D-Bus method returns successfully and the job is marked as cancelled, but **the underlying child process continues running**. This causes:
1. Device remains busy indefinitely
2. Inhibitor locks are not released
3. Subsequent operations on the device fail with "Device or resource busy"
4. System suspend/shutdown may be blocked
 

All operations using `UDisksSpawnedJob`:
- **Disk erase** (`Format 'empty'` with `'erase': 'zero'` or `'erase': 'ata-secure-erase'`) - **Critical**
- **Filesystem formatting** (mkfs.ext4, mkfs.xfs, etc.) - Moderate
- **Filesystem check** (fsck) - Moderate
- Any other spawned external commands 

## Additional Evidence### Test Logs```
[07:45:38] Starting wipe operation (cancelable job)...
[07:46:39] Found cancelable job: /org/freedesktop/UDisks2/jobs/1066
[07:46:39] Cancelling job...
[07:46:39] Job cancel request sent
[07:46:39] SUCCESS: Job cancellation tested# But the erase process continues!
[07:46:40] Found job: /org/freedesktop/UDisks2/jobs/1813
[07:46:40]   Operation: format-erase
[07:46:40]   Progress: 1.5%  ← Still running
[07:46:41]   Progress: 1.5%
[07:46:42]   Progress: 1.6%  ← Progressing
[07:46:43]   Progress: 1.6%

# Device cleanup fails
wipefs: error: /dev/sde: Device or resource busy

# Inhibitor leaked
Disk Manager   0   root 6768 udisksd   shutdown:sleep:idle Erasing Device   block
 

```python
import dbus
import time
import subprocess# Setup
bus = dbus.SystemBus()
manager = bus.get_object('org.freedesktop.UDisks2', '/org/freedesktop/UDisks2/Manager')

# Start long operation
block_obj = bus.get_object('org.freedesktop.UDisks2', '/org/freedesktop/UDisks2/block_devices/sde')
block_iface = dbus.Interface(block_obj, 'org.freedesktop.UDisks2.Block')

# Format with erase (long operation)
block_iface.Format('empty', {'erase': 'zero'})# Wait for job to start
time.sleep(2)# Find and cancel the job
jobs = ... 

# Get job list
job_iface.Cancel({})

# ✅ PASS: No dd process should be running
result = subprocess.run(['pgrep', '-f', 'dd.*sde'], capture_output=True)
assert result.returncode != 0, "FAIL: dd process still running after cancel"


# ✅ PASS: Device should be accessible
result = subprocess.run(['wipefs', '-a', '/dev/sde'], capture_output=True)
assert result.returncode == 0, "FAIL: Device still busy after cancel"
```
 


Disk Manager 0 root 6768 udisksd shutdown:sleep:idle Erasing Device block