I am trying to understand the init process in the linux kernel which is the first process and is statically initialized with the INIT_TASK macro.
161 #define INIT_TASK(tsk) \
162 { \
163 .state = 0, \
164 .stack = &init_thread_info, \
165 .usage = ATOMIC_INIT(2), \
166 .flags = PF_KTHREAD, \
167 .prio = MAX_PRIO-20, \
168 .static_prio = MAX_PRIO-20, \
169 .normal_prio = MAX_PRIO-20, \
170 .policy = SCHED_NORMAL, \
171 .cpus_allowed = CPU_MASK_ALL, \
172 .nr_cpus_allowed= NR_CPUS, \
173 .mm = NULL, \
174 .active_mm = &init_mm, \
175 .se = { \
176 .group_node = LIST_HEAD_INIT(tsk.se.group_node), \
177 }, \
178 .rt = { \
179 .run_list = LIST_HEAD_INIT(tsk.rt.run_list), \
180 .time_slice = RR_TIMESLICE, \
181 }, \
182 .tasks = LIST_HEAD_INIT(tsk.tasks), \
183 INIT_PUSHABLE_TASKS(tsk) \
184 INIT_CGROUP_SCHED(tsk) \
185 .ptraced = LIST_HEAD_INIT(tsk.ptraced), \
186 .ptrace_entry = LIST_HEAD_INIT(tsk.ptrace_entry), \
187 .real_parent = &tsk, \
188 .parent = &tsk, \
189 .children = LIST_HEAD_INIT(tsk.children), \
190 .sibling = LIST_HEAD_INIT(tsk.sibling), \
191 .group_leader = &tsk, \
192 RCU_POINTER_INITIALIZER(real_cred, &init_cred), \
193 RCU_POINTER_INITIALIZER(cred, &init_cred), \
194 .comm = INIT_TASK_COMM, \
195 .thread = INIT_THREAD, \
196 .fs = &init_fs, \
197 .files = &init_files, \
198 .signal = &init_signals, \
199 .sighand = &init_sighand, \
200 .nsproxy = &init_nsproxy, \
201 .pending = { \
202 .list = LIST_HEAD_INIT(tsk.pending.list), \
203 .signal = {{0}}}, \
204 .blocked = {{0}}, \
205 .alloc_lock = __SPIN_LOCK_UNLOCKED(tsk.alloc_lock), \
206 .journal_info = NULL, \
207 .cpu_timers = INIT_CPU_TIMERS(tsk.cpu_timers), \
208 .pi_lock = __RAW_SPIN_LOCK_UNLOCKED(tsk.pi_lock), \
209 .timer_slack_ns = 50000, /* 50 usec default slack */ \
210 .pids = { \
211 [PIDTYPE_PID] = INIT_PID_LINK(PIDTYPE_PID), \
212 [PIDTYPE_PGID] = INIT_PID_LINK(PIDTYPE_PGID), \
213 [PIDTYPE_SID] = INIT_PID_LINK(PIDTYPE_SID), \
214 }, \
215 .thread_group = LIST_HEAD_INIT(tsk.thread_group), \
216 INIT_IDS \
217 INIT_PERF_EVENTS(tsk) \
218 INIT_TRACE_IRQFLAGS \
219 INIT_LOCKDEP \
220 INIT_FTRACE_GRAPH \
221 INIT_TRACE_RECURSION \
222 INIT_TASK_RCU_PREEMPT(tsk) \
223 INIT_CPUSET_SEQ \
224 INIT_VTIME(tsk) \
225 }
But I am not able to figure out
how it will be executed?
Where it is scheduled and
which lines of code in the linux kernel start executing immediately when we say we have scheduled this init_task task? Is there any function which it calls?