AoU: ETAS_RTACAR_SM_OS_018¶

The ETAS_RTACAR_SM_OS_018 AoU verifies that when extended tasks are used in the RTA-OS configuration, mandatory stack size configuration parameters are properly defined for any task that can be preempted by an extended task.

Extended tasks in AUTOSAR OS are tasks that can use the WaitEvent() service to enter a waiting state, releasing the processor while waiting for an event to occur. Because extended tasks can be preempted and later resumed, they require explicit stack size configuration to ensure sufficient memory is allocated for their execution context.

Verification Approach¶

The verification is performed by analyzing the OS ECUC configuration files (ARXML) provided via the --os-arxml parameter or discovered in the project directory specified by --dir.

The tool performs the following steps:

Configuration Loading: Parses the ARXML files to extract the OS configuration, including task definitions and their properties.
Extended Task Detection: Identifies tasks configured as extended tasks (tasks that reference events via OsTaskEventRef).
Scalability Class Validation: Checks that the OsScalabilityClass parameter is consistent across all configuration files. If incompatible values are detected, manual verification is required.
Result Reporting: Generates one of the following results based on the analysis outcome.

Important

Automated Verification Scope

The current implementation detects the presence of extended tasks in the ECUC configuration but does not yet implement full automated verification of the stack size configuration constraints specified in the AoU.

When extended tasks are detected, the tool reports a review result, requiring manual verification that:

Stack size has been specified for any task that can be preempted by an extended task.

The stack size is sufficient for the task’s execution context and any nested preemptions.

This manual verification must confirm compliance with the complete AoU requirement as stated in the RTA-CAR Safety Manual.

ARXML Configuration Requirements¶

To enable this check, the OS ECUC configuration must be provided in AUTOSAR ARXML format. The tool analyzes:

Task definitions (OsTask containers) to identify extended tasks
Event references (OsTaskEventRef) to determine which tasks are extended
Scalability class settings (OsScalabilityClass) to ensure configuration consistency

Rule Id	ETAS_RTACAR_SM_OS_018
Title	If extended tasks are used, the stack size must be specified for any task that can be preempted by an extended task.
Description	This rule verifies that when extended tasks are used, the project defines mandatory configuration parameters related to stack size.

Message Description¶

id_000

Id	id_000
Message	Issue detected while executing the verification.
Kind	Open
Level	None
Description	An internal exception occurred during the execution. This can happen if there are insufficient resources available on the host machine, or if the ARXML configuration files cannot be properly parsed. For more details, please consult the RTA-SQF log file.
How To Fix	Restart the command to exclude any internal exceptions. Verify that the ARXML files are well-formed and accessible. Alternatively, please contact ETAS GmbH support for assistance. When reporting the error, include a sample configuration and command line that reproduces the issue.

id_001

Id	id_001
Message	No extended tasks were detected in the ECUC configuration; the AoU constraint is satisfied by default.
Kind	Pass
Level	None
Description	The analysis of the OS ECUC configuration did not detect any extended tasks. Since the AoU constraint only applies when extended tasks are present, the check passes trivially. The check is limited to the scenario(s) documented in the RTA-SQF User Manual. Please refer to the manual for more information.
How To Fix	Everything is in order. No action is required.

id_002

Id	id_002
Message	Extended tasks were detected in the ECUC configuration. The automated verification of the associated configuration constraints is not yet implemented. Manual verification is required to confirm that all constraints specified in the AoU have been met.
Kind	Review
Level	None
Description	The tool detected one or more extended tasks in the OS configuration (tasks that reference events via OsTaskEventRef), but the full automated verification of stack size configuration constraints is not yet implemented. Manual verification is required to ensure that the stack size has been specified for any task that can be preempted by an extended task. The check is limited to the scenario(s) documented in the RTA-SQF User Manual. Please refer to the manual for more information.
How To Fix	Manually verify the following: (1) Identify all extended tasks in your OS configuration. (2) Identify all tasks that can be preempted by any extended task, considering task priorities, preemption policies, and potential preemption chains. (3) Verify that OsTaskStackSize is explicitly configured for all tasks identified in step 2. (4) Confirm that the configured stack sizes are sufficient based on static analysis, worst-case execution path analysis, or runtime measurements. Document your verification in your project’s safety documentation.

id_003

Id	id_003
Message	No ECUC configuration was found. Manual verification is required to confirm that all constraints specified in the AoU have been met.
Kind	Review
Level	None
Description	No OS ECUC configuration was found in the provided ARXML files or project directory. This may occur if the –os-arxml parameter was not specified and no ARXML files were found in the project directory (–dir), or if the ARXML files do not contain OS configuration data (OsTask containers). Manual verification is required to ensure compliance with the AoU constraint. The check is limited to the scenario(s) documented in the RTA-SQF User Manual. Please refer to the manual for more information.
How To Fix	Verify that ARXML files containing the OS ECUC configuration are provided via the –os-arxml parameter or are present in the project directory specified by –dir. If OS configuration is not available in ARXML format, manually verify that the stack size requirement specified in the AoU is met: if extended tasks are used, ensure that the stack size has been specified for any task that can be preempted by an extended task.

id_004

Id	id_004
Message	Incompatible values were detected for {0} param. Manual verification is required.
Kind	Review
Level	None
Description	The tool detected incompatible values for the OsScalabilityClass parameter across multiple ARXML configuration files. This inconsistency prevents the tool from reliably determining the OS configuration state. Manual verification is required to resolve the configuration issue and confirm compliance with the AoU constraint. The check is limited to the scenario(s) documented in the RTA-SQF User Manual. Please refer to the manual for more information.
How To Fix	Review the OS configuration files and ensure that the OsScalabilityClass parameter has a consistent value across all ARXML files. Resolve any inconsistencies in the configuration. After correcting the configuration, re-run the RTA-SQF tool to verify the constraint.

AoU: ETAS_RTACAR_SM_OS_018¶

Verification Approach¶

ARXML Configuration Requirements¶

Message Description¶

See Also¶