Gate2017 cs Q57

57A multithreaded program P executes with x number of threads and uses y number of locks for ensuring mutual exclusion while operating on shared memory locations. All locks in the program are non-re-entrant, i.e., if a thread holds a lock l, then it cannot re-acquire lock l without releasing it. If a thread is unable to acquire a lock, it blocks until the lock becomes available. The minimum value of x and the minimum value of y together for which execution of P can result in a deadlock are:

Option : D
Explanation : Reentrant property is provided, so that a process who owns a lock, can acquire same lock multiple times. Here it is non-reentrant as given, process cant own same lock multiple times. So if a thread tries to acquire already owned lock, will get blocked, and this is a deadlock.
Hence correct answer is x=1, y=1.

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