DFA failure initiators#

Note

Use all applicable failure initiators to ensure a structured analysis. If there are additional failure initiators needed, please enlarge the list of fault models.

Note

An ASIL related message is trustable in that manner that it is not corrupted, repeated, lost, delayed, masqueraded or addressed incorrectly.

Purpose

In order to identify all cascading and common cause failures, which may initiated from your feature or components to the platform, other features, components, etc., use the following framework of dependent failure initiators to check your completeness of the analysis.

DFA failure initiators#

2.1 Shared resources

Note

Shared libraries are only than to be considered as a shared resource if the feature and the related safety mechanisms are using this specific library. If the library is not used by the feature or the related safety mechanisms, it is not a shared resource.

Table 39 DFA shared resources (used for Platform DFA)#

ID

Violation cause shared resources

Importance (can be used for prioritization)

SR_01_01

Reused software modules

Medium

SR_01_02

Libraries

Medium

SR_01_04

Basic software

Medium

SR_01_05

Operating system including scheduler

Medium

SR_01_06

Any service stack, e.g. communication stack

Medium

SR_01_07

Configuration data

Medium

SR_01_09

Execution time

Medium

SR_01_10

Allocated memory

Medium
2.2 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 40 DFA communication between elements#

ID

Violation cause communication between elements

Importance (can be used for prioritization)

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)

Medium

CO_01_02

Data or message corruption / repetition / loss / delay / masquerading or incorrect addressing of information

Medium

CO_01_03

Insertion / sequence of information

Medium

CO_01_04

Corruption of information, inconsistent data

Medium

CO_01_05

Asymmetric information sent from a sender to multiple receivers, so that not all defined receivers have the same information

Medium

CO_01_06

Information from a sender received by only a subset of the receivers

Medium

CO_01_07

Blocking access to a communication channel

Medium
2.3 Shared information inputs
Same information input used by multiple functions.
Table 41 DFA shared information inputs#

ID

Violation cause shared information inputs

Importance (can be used for prioritization)

SI_01_02

Configuration data

Medium

SI_01_03

Constants, or variables, being global to the two software functions

Medium

SI_01_04

Basic software passes data (read from hardware register and converted into logical information) to two applications software functions

Medium

SI_01_05

Data / function parameter arguments / messages delivered by software function to more than one other function

Medium
2.4 Unintended impact
Unintended impacts to function due to various failures.
Table 42 DFA unintended impact#

ID

Violation cause unintended impact

Importance (can be used for prioritization)

UI_01_01

Memory miss-allocation and leaks

Medium

UI_01_02

Read/Write access to memory allocated to another software element

Medium

UI_01_03

Stack/Buffer under-/overflow

Medium

UI_01_04

Deadlocks

Medium

UI_01_05

Livelocks

Medium

UI_01_06

Blocking of execution

Medium

UI_01_07

Incorrect allocation of execution time

Medium

UI_01_08

Incorrect execution flow

Medium

UI_01_09

Incorrect synchronization between software elements

Medium

UI_01_10

CPU time depletion

Medium

UI_01_11

Memory depletion

Medium

UI_01_12

Other HW unavailability

Medium
Development failure initiators
Section is only applicable if a divers SW development is needed due to decomposition.
note:

Section shall be applied only once to analyse all dependencies of the features. Results shall be checked during of the analysis of new features if this is applicable to the feature.

Table 43 DFA development failure initiators (Platform DFA)#

ID

Violation cause development failure initiators

Importance (can be used for prioritization)

SC_01_02

Same development approaches (e.g. IDE, programming and/or modelling language)

Medium

SC_01_03

Same personal

Medium

SC_01_04

Same social-cultural context (even if different personnel). Only applicable if diverse development is needed.

Medium

SC_01_05

Development fault (e.g. human error, insufficient qualification, insufficient methods). Only applicable if diverse development is needed.

Medium