Identify ISR Bug in Code Snippet | Dataford Interview Questions

Given a snippet of embedded code, identify what is wrong with it (bug related to interrupt service routines). Asked in the initial interview stage. This was a 45-min first-round embedded interview, followed by tangential technical questions and OS trivia.

Implement identify_isr_bugs(code). Return issue labels in this order: blocking_call, dynamic_allocation, shared_state_not_volatile, and non_atomic_shared_access. Treat functions containing ISR( or interrupt as handlers. Detect delay, sleep, or wait calls, allocation calls, non-volatile global variables referenced by a handler, and mutations of volatile shared variables.

Constraints

1 <= len(code) <= 100000
The input is a C or C-like embedded source snippet
Handlers are identified by ISR( or interrupt
Global scalar declarations use a supported integer or boolean type
Return issue labels in the specified order without duplicates

Function Signature

def identify_isr_bugs(code):

Your question is Identify ISR Bug in Code Snippet. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.

Problem

Constraints

1 <= len(code) <= 100000
The input is a C or C-like embedded source snippet
Handlers are identified by ISR( or interrupt
Global scalar declarations use a supported integer or boolean type
Return issue labels in the specified order without duplicates

Function Signature

def identify_isr_bugs(code):

Your question is Identify ISR Bug in Code Snippet. Start with the requirements in the Question tab.

Run and submit as often as you like. When you're ready, talk me through your approach or go straight to the code.