Questions tagged [deadlocks]

In OS, a deadlock is where two or more processes are waiting indefinitely for an event that can be caused by one of the waiting processes. Deadlock is a common problem in distributed systems, parallel computing & multiprocessing systems.

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What happens if the holder of a lock tries to acquire a lock? [closed]

In a system, suppose there is a process and a resource with only one instance. Let us assume that the process holds the instance and requests the same instance of that resource. Will there be a ...
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Is Bounded Waiting satisfied for this 2 process Solution?

This is my new post linked with my previous post. Is bounded waiting satisfied in the 2 Process Solution? The answer in that post was very useful and cleared many concepts, but I just want to apply ...
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How to build/recognise a deadlock-free order of resources

I have been faced with a problem where three concurrent processes X, Y ,Z execute three different code segments that access and update certain shared variables. Before entering the respective code ...
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Deadlock and safe state

I read that system being in safe state doesn't guarantee that deadlock is not possible. Can someone give me an example where system is in safe state and deadlock is possible?
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Deadlock not possible?

System is in safe state if there exists a safe sequence of all processes. Sequence $[P_1, P_2 …P_n]$ is safe, if for each $P_i$ the resources that can still request can be satisfied by $P_i$ ...
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Is bounded waiting satisfied in this 2 process solution?

Two processes, P1 and P2, need to access a critical section of code. Consider the following synchronization construct used by the processes: ...
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Some Problem To Understand Petri Nets for detect deadlock in 2PL Locking

hi i read a paper and some section it's not clear for me please help me to understand it.. paper topic: A Deadlock Prevention Algorithm for The TwoPhase Locking Protocol Based on Petri Net basic ...
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Does Dekkers solutions to critical section problem ensure progress?

I was reading concurrency control section from Operating Systems book by William Stallings. In this book, he gives three attempts by Dekker to give solution to critical section problem: Attempt 1 <...
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Is this a deadlock?

Consider we have two processes P1 and P2. There are also two semaphores M and N which are initialized to zero. Here's how they execute: ...
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Deadlock: can the processes know about deadlock occurrence

Deadlock can happen when two processes are waiting for resources held by each other. Here can the two processes know that they are waiting for each other to release resources?
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Does a safe state ensures there will never ever be a deadlock?

In Banker's algorithm of deadlock avoidance, if one can obtain a safe state, does that necessarily mean there will never be a deadlock, or is there still some way that the system could fall into a ...
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What are necessity and sufficiency?

I was reading deadlock topic from Operating Systems book by Stallings. It states four pre requisites for deadlock: Mutual exclusion No preemption Hold and wait Circular wait It then have following ...
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Banker's algorithm

I have a question regarding the banker's algorithm step 2. When it says the Need[i] <= work. Need is an n * m matrix and work is a vector of length m. I want to know what Need[i] <= Work means. ...
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Deadlock necessary conditions [duplicate]

I read that the 4 conditions for deadlock prevention are necessary conditions and not sufficient. The four necessary conditions are :- Mutual exclusion. Hold and wait. No preemption. Circular wait. ...
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2 phase locking with added increment mode

Suppose that a DBMS recognizes increment as an atomic operation, in addition to the read and ...
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I have a question about resource alocation to avoid dead lock

In the code below, three processes are competing for six resources labeled A to F.How can I modify the get request in each procedure in this graph to avoid dead lock You cannot move requests ...
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Deadlocks in operating System

Consider a system with 6 processes, where each process needs 2 copies of Resource R. The maximum units of R required to cause deadlock is ??
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A Dead-lock in an Operating System is

A Dead-lock in an Operating System is Desirable process Undesirable process Definite waiting process All of the above My attempt: As "If a process is unable to change its state indefinitely because ...

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