DFA (Dependent Failure Analysis)

result DFA		status: valid security: NO safety: ASIL_B
version: 2 realizes: wp__sw_component_dfa
doc__result_dfa		Generic Document

Note

Use the content of the document to describe e.g. why a fault model is not applicable for the diagram.

Dependent Failure Initiators

Shared resources

The dependent failure initiators related to shared resources are not applicable for the component. The shared resources are considered in the platform and feature DFA.

Communication between the two elements

Receiving function is affected by information that is false, lost, sent multiple times, or in the wrong order etc. from the sender.

Table 48 DFA communication between elements

ID	Violation cause communication between elements	Applicability	Rationale
CO_01_01	Information passed via argument through a function call, or via writing/reading a variable being global to the two software functions (data flow)	Yes	Call to used libcpp can return wrong values, Result component FFI (comp_saf_dfa__result__ffi)
CO_01_02	Data or message corruption / repetition / loss / delay / masquerading or incorrect addressing of information	no	No messages between result and used Libcpp functions.
CO_01_03	Insertion / sequence of information	no	No messages between result and used Libcpp functions.
CO_01_04	Corruption of information, inconsistent data	no	No messages between result and used Libcpp functions.
CO_01_05	Asymmetric information sent from a sender to multiple receivers, so that not all defined receivers have the same information	no	No messages between result and used Libcpp functions.
CO_01_06	Information from a sender received by only a subset of the receivers	no	No messages between result and used Libcpp functions.
CO_01_07	Blocking access to a communication channel	no	No communication channel shared between result and used Libcpp functions.

Shared information inputs

Same information input used by multiple functions.

Table 49 DFA shared information inputs

ID	Violation cause shared information inputs	Applicability	Rationale
SI_01_02	Configuration data	no	No shared configuration data between result and used Libcpp functions.
SI_01_03	Constants, or variables, being global to the two software functions	no	No global data used by result and used Libcpp functions.
SI_01_04	Basic software passes data (read from hardware register and converted into logical information) to two applications software functions	no	result and used Libcpp functions are not sharing HW related data.
SI_01_05	Data / function parameter arguments / messages delivered by software function to more than one other function	no	Not expected for result and used Libcpp functions.

Unintended impact

Unintended impacts to function due to various failures.

Table 50 DFA unintended impact

ID	Violation cause unintended impact	Applicability	Rationale
UI_01_01	Memory miss-allocation and leaks	no	Not a specific bitmnipulation topic, therefore covered at platform DFA.
UI_01_02	Read/Write access to memory allocated to another software element	yes	result and used Libcpp functions are in same memory space so the memory could be corrupted, Result component FFI (comp_saf_dfa__result__ffi)
UI_01_03	Stack/Buffer under-/overflow	no	Not a specific result topic, therefore covered at platform DFA.
UI_01_04	Deadlocks	yes	Not a specific result topic, therefore covered at feature level.
UI_01_05	Livelocks	no	Not a specific result topic, therefore covered at feature level.
UI_01_06	Blocking of execution	yes	Used Libcpp functions may block result, Result component FFI (comp_saf_dfa__result__ffi)
UI_01_07	Incorrect allocation of execution time	no	Execution time allocated by (external) OS on platform level, should be covered centrally at platform level.
UI_01_08	Incorrect execution flow	no	Execution flow controlled by (external) OS on platform level, should be covered centrally at platform level.
UI_01_09	Incorrect synchronization between software elements	no	result and used Libcpp functions have no synchronization needs.
UI_01_10	CPU time depletion	yes	Used Libcpp functions may deplete result’s CPU time, Result component FFI (comp_saf_dfa__result__ffi)
UI_01_11	Memory depletion	no	Not a specific result topic, therefore covered at platform DFA.
UI_01_12	Other HW unavailability	no	No special HW used for baselibs.

DFA

For all identified applicable failure initiators, the DFA is performed in the following section.

Result component FFI		status: valid
failure_effect: result and used Libcpp functions influence each other and cause wrong read or write of error/result data failure_id: CO_01_01,UI_01_02,UI_01_06,UI_01_10 sufficient: yes version: 1 mitigated_by: aou_req__platform__os_safety_functions violates: comp_arc_sta__baselibs__result
Used C++ standard library (libcpp) functions are required to be provided at least as ASIL_B.
comp_saf_dfa__result__ffi		Component DFA (Dependent Failure Analysis)