GATE CS 2022 Set 1 — Question 26

MSQ+1 / -0MediumDeadlocksOperating System

Operating System → Deadlocks

Last updated 5 September 2026

Question

Which of the following statements is/are TRUE with respect to deadlocks?

Correct answer (A) Circular wait is a necessary condition for the formation of deadlock.; (D) In the resource-allocation graph of a system, if every edge is an assignment edge, then the system is not in deadlock state. Solution 1. Statement (A): According to Coffman's conditions, Circular Wait is one of the four necessary conditions for a deadlock to occur. True. 2. Statement (B): In a system with multiple instances of resources, a cycle in the Resource Allocation Graph (or wait-for graph) is a necessary but not sufficient condition for deadlock. A knot is required, or graph reduction must be checked. False. 3. Statement (C): An unsafe state implies that the system may enter a deadlock, but it is not guaranteed. A deadlock will necessarily occur only if the system cannot avoid it regardless of future requests, but an unsafe state just means there is no guaranteed safe sequence; dynamic execution might still avoid deadlock. False. 4. Statement (D): An assignment edge goes from a Resource to a Process (R \to P), indicating the process holds the resource. If every edge is an assignment edge, there are no request edges (P \to R), meaning no process is waiting for a resource. Without waiting, there is no deadlock. True. Turn this into a strength. Explore AI-powered practice and doubt support with Success Tracker.

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Correct answer (A) Circular wait is a necessary condition for the formation of deadlock.; (D) In the resource-allocation graph of a system, if every edge is an assignment edge, then the system is not in deadlock state. Solution 1. Statement (A): According to Coffman's conditions, Circular Wait is one of the four necessary conditions for a deadlock to occur. True. 2. Statement (B): In a system with multiple instances of resources, a cycle in the Resource Allocation Graph (or wait-for graph) is a necessary but not sufficient condition for deadlock. A knot is required, or graph reduction must be checked. False. 3. Statement (C): An unsafe state implies that the system may enter a deadlock, but it is not guaranteed. A deadlock will necessarily occur only if the system cannot avoid it regardless of future requests, but an unsafe state just means there is no guaranteed safe sequence; dynamic execution might still avoid deadlock. False. 4. Statement (D): An assignment edge goes from a Resource to a Process (R \to P), indicating the process holds the resource. If every edge is an assignment edge, there are no request edges (P \to R), meaning no process is waiting for a resource. Without waiting, there is no deadlock. True.

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