Consider the following code (with line numbers): ! typedef struct lock_t (int flag; ) lock_t; void init (lock_t mutex) ( 11 12 13 15 // 0-> lock is available, 1 -> held mutex->flag = 0; void lock (lock_t *mutex) ( while (mutex->flag == 1) // TEST the flag ; // spin-wait (do nothing) mutex->flag = 1; // now SET it! } void unlock (lock_t mutex) ( mutex->flag = 0; This code is defective in that it allows two threads to enter a critical section at the same time. Please give me a sequence of operations where this might occur.

Consider the following code (with line numbers): ! typedef struct lock_t (int flag; ) lock_t; void init (lock_t mutex) ( 11 12 13 15 // 0-> lock is available, 1 -> held mutex->flag = 0; void lock (lock_t *mutex) ( while (mutex->flag == 1) // TEST the flag ; // spin-wait (do nothing) mutex->flag = 1; // now SET it! } void unlock (lock_t mutex) ( mutex->flag = 0; This code is defective in that it allows two threads to enter a critical section at the same time. Please give me a sequence of operations where this might occur.

Database System Concepts

7th Edition

ISBN:9780078022159

Author:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Publisher:Abraham Silberschatz Professor, Henry F. Korth, S. Sudarshan

Chapter1: Introduction

Section: Chapter Questions

Problem 1PE

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