161주차 (2016.10.29) rest_init()

arm
linux

#1

Neuromancer : 161 주차

일시 : 2016.10.29 (161 주차 스터디 진행)

모임명 : neuromancer.kr

장소 : 토즈 서현점

참여인원 : 2명

============

161주차 진도

  • 161차 시작 위치
    • start_kernel 1 ~/init/main.c
    • rest_init 968 ~/init/main.c
    • kernel_thread 453 ~/init/main.c
    • do_fork 2067 ~/kernel/fork.c
    • copy_process 2020 ~/kernel/fork.c
    • sched_fork 1734 ~/kernel/fork.c

161주차 함수 호출 구조

  • call: start_kernel()
  • lockdep_init()
  • smp_setup_processor_id()
  • debug_objects_early_init()
  • boot_init_stack_canary()
  • cgroup_init_early()
  • local_irq_disable()
  • boot_cpu_init()
  • page_address_init()
  • pr_notice()
  • setup_arch()
  • mm_init_owner()
  • mm_init_cpumask()
  • setup_command_line
  • build_all_zonelists()
  • page_alloc_init()
  • pr_notice()
  • parse_early_param()
  • parse_args()
  • jump_label_init()
  • setup_log_buf()
  • pidhash_init()
  • vfs_caches_init_early()
  • sort_main_extable()
  • trap_init()
  • mm_init()
  • sched_init()
  • preempt_disable()
  • irqs_disabled()
  • local_irq_disabled()
  • idr_init_cache()
  • rcu_init()
  • tick_nohz_init()
  • contect_tracking_init()
  • radix_tree_init()
  • early_irq_init()
  • init_IRQ()
  • tick_init()
  • init_timers()
  • hrtimers_init()
  • softirq_init()
  • timekeeping_init()
  • time_init()
  • sched_clock_postinit()
  • pref_event_init()
  • profile_init()
  • call_function_init()
  • irqs_disabled()
  • local_irq_enabled()
  • kmem_cache_init_late()
  • console_init()
  • lockdep_init()
  • lockdep_info()
  • locking_selftest()
  • virt_to_page()
  • page_to_pfn()
  • page_cgroup_init()
  • debug_objects_mem_init()
  • kmemleak_init()
  • setup_per_cpu_pageset()
  • numa_policy_init()
  • sched_clock_init()
  • calibrate_delay()
  • pidmap_init()
  • anon_vma_init()
  • thread_info_cache_init()
  • cred_init()
  • fork_init()
  • proc_caches_init()
  • buffer_init()
  • key_init()
  • security_init()
  • dbg_late_init()
  • vfs_caches_init()
  • signals_init()
  • page_writeback_init()
  • proc_root_init()
  • cgroup_init()
  • cpuset_init()
  • taskstats_init_early()
  • delayacct_init()
  • check_bugs()
  • acpi_early_init()
  • sfi_init_late()
  • efi_enabled(EFI_RUNTIME_SERVICES)
  • ftrace_init()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starting()
  • kernel_thread()
  • call: kernel_thread()
  • do_fork()
  • call: do_fork()
  • copy_process()
  • call: copy_process()
  • security_task_create()
  • dup_task_struct()
  • ftrace_graph_init_task§; // null function
  • get_seccomp_filter§; // null function
  • rt_mutex_init_task§;
  • copy_creds(p, clone_flags);
  • try_module_get()
  • delayacct_tsk_init§
  • copy_flags()
  • INIT_LIST_HEAD(&p->children);
  • INIT_LIST_HEAD(&p->sibling);
  • rcu_copy_process§;
  • spin_lock_init(&p->alloc_lock);
  • init_sigpending(&p->pending);
  • memset(&p->rss_stat, 0, sizeof(p->rss_stat));
  • task_io_accounting_init(&p->ioac); // null function
  • acct_clear_integrals§; // null function
  • posix_cpu_timers_init§;
  • do_posix_clock_monotonic_gettime(&p->start_time);
  • monotonic_to_bootbased(&p->real_start_time);
  • cgroup_fork§;
  • sched_fork(clone_flags, p);
  • call: sched_fork(clone_flags, p);
  • get_cpu();
  • __sched_fork(clone_flags, p);
  • rt_prio(p->prio)

start_kernel()

  • call: start_kernel()
  • lockdep_init()
  • smp_setup_processor_id()
  • debug_objects_early_init()
  • boot_init_stack_canary()
  • cgroup_init_early()
  • local_irq_disable()
  • boot_cpu_init()
  • page_address_init()
  • pr_notice()
  • setup_arch()
  • mm_init_owner()
  • mm_init_cpumask()
  • setup_command_line
  • build_all_zonelists()
  • page_alloc_init()
  • pr_notice()
  • parse_early_param()
  • parse_args()
  • jump_label_init()
  • setup_log_buf()
  • pidhash_init()
  • vfs_caches_init_early()
  • sort_main_extable()
  • trap_init()
  • mm_init()
  • sched_init()
  • preempt_disable()
  • irqs_disabled()
  • local_irq_disabled()
  • idr_init_cache()
  • rcu_init()
  • tick_nohz_init()
  • contect_tracking_init()
  • radix_tree_init()
  • early_irq_init()
  • init_IRQ()
  • tick_init()
  • init_timers()
  • hrtimers_init()
  • softirq_init()
  • timekeeping_init()
  • time_init()
  • sched_clock_postinit()
  • pref_event_init()
  • profile_init()
  • call_function_init()
  • irqs_disabled()
  • local_irq_enabled()
  • kmem_cache_init_late()
  • console_init()
  • lockdep_init()
  • lockdep_info()
  • locking_selftest()
  • virt_to_page()
  • page_to_pfn()
  • page_cgroup_init()
  • debug_objects_mem_init()
  • kmemleak_init()
  • setup_per_cpu_pageset()
  • numa_policy_init()
  • sched_clock_init()
  • calibrate_delay()
  • pidmap_init()
  • anon_vma_init()
  • thread_info_cache_init()
  • cred_init()
  • fork_init()
  • proc_caches_init()
  • buffer_init()
  • key_init()
  • security_init()
  • dbg_late_init()
  • vfs_caches_init()
  • signals_init()
  • page_writeback_init()
  • proc_root_init()
  • cgroup_init()
  • cpuset_init()
  • taskstats_init_early()
  • delayacct_init()
  • check_bugs()
  • acpi_early_init()
  • sfi_init_late()
  • efi_enabled()
  • efi_late_init()
  • efi_free_boot_services()
  • ftrace_init()
  • rest_init()
// ARM10C 20130824
asmlinkage void __init start_kernel(void)
{
	char * command_line;
	extern const struct kernel_param __start___param[], __stop___param[];
	// ATAG,DTB 정보로 사용

	/*
	 * Need to run as early as possible, to initialize the
	 * lockdep hash:
	 */
	lockdep_init();
	smp_setup_processor_id();
	debug_objects_early_init();

	/*
	 * Set up the the initial canary ASAP:
	 */
	boot_init_stack_canary();

	cgroup_init_early();
	// cgroup 를 사용하기 위한 cgroup_dummy_root, cgroup_subsys 의 구조체 초기화 수행

	local_irq_disable();
	// IRQ를 disable 함

	early_boot_irqs_disabled = true;
	// early_boot_irqs_disabled: true

/*
 * Interrupts are still disabled. Do necessary setups, then
 * enable them
 */
	boot_cpu_init();
	// 현재 cpu(core id)를 얻어서 cpu_XXX_bits[] 의 cpu를 셋한다.
	
	page_address_init();
	// 128개의 page_address_htable 배열을 초기화

	pr_notice("%s", linux_banner);
	// 배너:
	//	Linux version 2.6.37_DM385_IPNC_3.50.00
	// 	([email protected]) (gcc version 4.5.3 20110311
	// 	(prerelease) (GCC) ) #1 Fri Dec 21 17:27:08 IST 2012

	setup_arch(&command_line);

	mm_init_owner(&init_mm, &init_task); // null function
	mm_init_cpumask(&init_mm); // null function

	// command_line: exynos5420-smdk5420.dts 파일의 chosen node 의 bootarg 값
	// "console=ttySAC2,115200 init=/linuxrc"
	setup_command_line(command_line);
	// saved_command_line 및 static_command_line 할당

	setup_nr_cpu_ids();
	setup_per_cpu_areas();
	// pcpu 구조체를 만들어 줌 (mm/percpu.c)

	smp_prepare_boot_cpu();	/* arch-specific boot-cpu hooks */
	// boot cpu 0의 pcpu 영역의 base주소를 core register에 설정해줌

	build_all_zonelists(NULL, NULL);

	page_alloc_init();
	// cpu_chain에 page_alloc_cpu_notify를 연결함 (mutex lock/unlock 사용)

	// boot_command_line: "console=ttySAC2,115200 init=/linuxrc"
	pr_notice("Kernel command line: %s\n", boot_command_line);
	// "Kernel command line: console=ttySAC2,115200 init=/linuxrc"

	parse_early_param();
	// setup_arch에서 수행했던 작업 다시 수행
	// command arg에서 각 요소들을 파싱하여 early init section으로 설정된 디바이스 초기화.
	// 우리는 serial device가 검색이 되지만 config설정은 없어서 아무것도 안함.

	// static_command_line: "console=ttySAC2,115200 init=/linuxrc"
	parse_args("Booting kernel", static_command_line, __start___param,
		   __stop___param - __start___param,
		   -1, -1, &unknown_bootoption);
	// DTB에서 넘어온 bootargs를 파싱하여 param, val을 뽑아내고 그에 대응되는
	// kernel_param 구조체에 값을 등록함.

	jump_label_init();
	// HAVE_JUMP_LABEL 이 undefined 이므로 NULL 함수

	/*
	 * These use large bootmem allocations and must precede
	 * kmem_cache_init()
	 */
	setup_log_buf(0);
	// defalut log_buf의 크기는 __LOG_BUF_LEN: 0x20000 (128KB) 임
	// early_param 에서 호출했던 log_buf_len 값이 있다면 log_buf의 크기를 넘어온 크기로 만듬

	pidhash_init();
	// pidhash의 크기를 16kB만큼 할당 받고 4096개의 hash list를 만듬

	vfs_caches_init_early();
	// Dentry cache, Inode-cache용 hash를 위한 메모리 공간을 각각 512kB, 256kB만큼 할당 받고,
	// 131072, 65536개 만큼 hash table을 각각 만듬

	sort_main_extable();
	// extable 을 cmp_ex를 이용하여 sort수행

	trap_init(); // null function

	mm_init();
	// buddy와 slab 을 활성화 하고 기존 할당 받은 bootmem 은 buddy,
	// pcpu 메모리, vmlist 는 slab으로 이관

	/*
	 * Set up the scheduler prior starting any interrupts (such as the
	 * timer interrupt). Full topology setup happens at smp_init()
	 * time - but meanwhile we still have a functioning scheduler.
	 */
	sched_init();
	// scheduler가 사용하는 자료 구조 초기화, idle_threads를 init_task로 세팅

	/*
	 * Disable preemption - early bootup scheduling is extremely
	 * fragile until we cpu_idle() for the first time.
	 */
	preempt_disable();
	// preempt count를 증가시켜 preemption 못하도록 막음

	// irqs_disabled(): 1
	if (WARN(!irqs_disabled(), "Interrupts were enabled *very* early, fixing it\n"))
		local_irq_disable();

	idr_init_cache();
	// integer ID management로 사용하는 idr_layer_cache에 kmem_cache#21 을 생성 및 초기화 후 할당

	rcu_init();
	// rcu 자료구조 bh, sched, preempt 를 각각 초기화 수행함

	tick_nohz_init(); // null function
	context_tracking_init(); // null function

	radix_tree_init();
	// radix tree로 사용하는 radix_tree_node_cachep에 kmem_cache#20을 생성 및 초기화 후 할당하고
	// height_to_maxindex을 초기화 수행

	/* init some links before init_ISA_irqs() */
	early_irq_init();
	// irq_desc 0 ~ 15 까지의 object을 할당 받고 초기화를 수행
	// allocated_irqs에 bit를 1로 세팅하고 radix tree에 각 irq_desc를 노트로 추가

	init_IRQ();
	// gic, combiner이 사용할 메모리 할당과 자료 구조 설정,
	// gic irq (0~15), combiner irq (32~63) interrupt 를 enable 시킴

	tick_init();
	// tick 관련 mask 변수를 0으로 초기화 수행

	init_timers();
	// boot_tvec_bases의 맴버 값을 초기화하고 timers_nb를 cpu_notifier 에 등록,
	// softirq_vec[1] 에 run_timer_softirq 등록하여 초기화 수행

	hrtimers_init();
	// hrtimer_bases의 맴버 값을 초기화하고 hrtimers_nb를 cpu_notifier 에 등록,
	// softirq_vec[8] 에 run_hrtimer_softirq 등록하여 초기화 수행

	softirq_init();
	// tasklet_vec, tasklet_hi_vec 맴버 값을 초기화하고,
	// softirq_vec[6]에 tasklet_action, softirq_vec[0]에 tasklet_hi_action 등록하여 초기화 수행

	timekeeping_init();
	// ntp 관련 전역변수 초기화, timekeeper, shadow_timekeeper의 맴버값 초기화 수행

	time_init();
	// timer 를 사용하기 위한 clk source, clk_table 메모리 할당 및 초기화,
	// timer event를 위한 timer irq (MCT) 초기화 수행

	sched_clock_postinit();
	// sched_clock_timer을 초기화 수행

	perf_event_init(); // null function
	profile_init(); // null function
	call_function_init();
	// 각 cpu core에서 사용할 call_single_queue를 맴버값 초기화
	// cfd_data 맴버값을 초기화하고 pcp에서 사용할 메모리 공간 할당
	// cpu_chain에 hotplug_cfd_notifier 를 등록함

	// irqs_disabled(): 1
	WARN(!irqs_disabled(), "Interrupts were enabled early\n");

	// early_boot_irqs_disabled: true
	early_boot_irqs_disabled = false;
	// early_boot_irqs_disabled: false

	local_irq_enable();
	// IRQ를 enable 함

	kmem_cache_init_late(); // null function

	/*
	 * HACK ALERT! This is early. We're enabling the console before
	 * we've done PCI setups etc, and console_init() must be aware of
	 * this. But we do want output early, in case something goes wrong.
	 */
	console_init();

	// panic_later: NULL
	if (panic_later)
		panic(panic_later, panic_param);

	lockdep_info(); // null function

	/*
	 * Need to run this when irqs are enabled, because it wants
	 * to self-test [hard/soft]-irqs on/off lock inversion bugs
	 * too:
	 */
	locking_selftest(); // null function

#ifdef CONFIG_BLK_DEV_INITRD // CONFIG_BLK_DEV_INITRD=y
	// initrd_start: NULL, initrd_below_start_ok: 0
	if (initrd_start && !initrd_below_start_ok &&
	    page_to_pfn(virt_to_page((void *)initrd_start)) < min_low_pfn) {
		pr_crit("initrd overwritten (0x%08lx < 0x%08lx) - disabling it.\n",
		    page_to_pfn(virt_to_page((void *)initrd_start)),
		    min_low_pfn);
		initrd_start = 0;
	}
#endif

	page_cgroup_init(); // null function
	debug_objects_mem_init(); // null function
	kmemleak_init(); // null function

	setup_per_cpu_pageset();
	// per cpu가 사용하는 pageset의 각각의 zone 맴버값 초기화 수행

	numa_policy_init(); // null function

	// late_time_init: NULL
	if (late_time_init)
		late_time_init();

	sched_clock_init();
	// sched_clock_running 값을 1 로 초기화 수행

	calibrate_delay();
	// BogoMIPS값을 결정하기위한 계산을 수행하고 결과를 출력함

	pidmap_init();
	// pidmap 을 사용하기 위한 초기화 수행

	anon_vma_init();
	// anon vma 를 사용하기 위한 kmem_cache 할당자 초기화 수행

#ifdef CONFIG_X86 // CONFIG_X86=n
	if (efi_enabled(EFI_RUNTIME_SERVICES))
		efi_enter_virtual_mode();
#endif
	thread_info_cache_init(); // null function
	cred_init();
	// credentials 를 사용하기 위한 kmem_cache 할당자 초기화 수행

	// totalram_pages: 총 free된 page 수
	fork_init(totalram_pages);
	// task_struct 를 사용하기 위한 kmem_cache 할당자 초기화 수행
	// max_threads값을 계산하여 init_task에 threads값의 limit 값 설정함

	proc_caches_init();
	// sighand_struct, signal_struct, files_struct, fs_struct, mm_struct, vm_area_struct, nsproxy
	// 를 사용하기 위한 kmem_cache 할당자 및 percpu list 초기화 수행

	buffer_init();
	// buffer_head 를 사용하기 위한 kmem_cache 할당자 및 max_buffer_heads 값 초기화 수행

	key_init(); // null funtion
	security_init(); // null funtion
	dbg_late_init(); // null funtion

	// totalram_pages: 총 free된 page 수
	vfs_caches_init(totalram_pages);
	// virtual file system을 위한 names, dentry, inode, filp, mount cache 생성 후
	// file system 을 위한 초기화 수행 및 mount 수행, block, char dev 사용을 위한 초기화 수행

	signals_init();
	// signal을 사용하기 위한 kmem_cache 를 생성

	/* rootfs populating might need page-writeback */
	page_writeback_init();
	// page writeback을 위한 global_dirty_limit, ratelimit_pages 값을 초기화 수행

#ifdef CONFIG_PROC_FS // CONFIG_PROC_FS=y
	proc_root_init();
	// proc filesystem을 등록 하고 proc을 사용하기 위한 dentry, inode 생성 후
	// sysctl_base_table 에 등록된 kernel, vm, fs, debug, dev의 dir, files 를 recursive 하게 RB Tree 를 구성함
#endif
	cgroup_init();
	// cgroup에서 사용하는 sub system 인 debug_subsys, cpu_cgroup_subsys, cpuacct_subsys, freezer_subsys 를 등록 하고
	// init_css_set.subsys 를 이용하여 hash key 값 생성, cgroup 을 위한 kobject 를 생성, cgroup용 fils system type을 추가 하여
	// filesystem 에 등록함, cgroup 을 위한 proc 생성.

	cpuset_init(); // null function
	taskstats_init_early(); // null function
	delayacct_init(); // null function

	check_bugs();
	// page 2개를 할당 받고 할당 받은 메모리에값을 쓰고 비교하여
	// 메모리 동작을 테스트 수행한 이후 다시 메모리를 반환함

	acpi_early_init(); /* before LAPIC and SMP init */  // null function
	sfi_init_late(); // null function

	// efi_enabled(EFI_RUNTIME_SERVICES): 1
	if (efi_enabled(EFI_RUNTIME_SERVICES)) {
		efi_late_init(); // null function
		efi_free_boot_services(); // null function
	}

	ftrace_init(); // null function

	/* Do the rest non-__init'ed, we're now alive */
	rest_init();
}	

rest_init()

  • start_kernel()
  • rest_init()
  • call: rest_init()
// ARM10C 20160827
static noinline void __init_refok rest_init(void)
{
	int pid;

	rcu_scheduler_starting(); // null function
	/*
	 * We need to spawn init first so that it obtains pid 1, however
	 * the init task will end up wanting to create kthreads, which, if
	 * we schedule it before we create kthreadd, will OOPS.
	 */
	// CLONE_FS: 0x00000200, CLONE_SIGHAND: 0x00000800
	kernel_thread(kernel_init, NULL, CLONE_FS | CLONE_SIGHAND);

kernel_thread()

  • start_kernel()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starting()
  • kernel_thread()
// ARM10C 20160827
// kernel_init, NULL, 0x00000A00
pid_t kernel_thread(int (*fn)(void *), void *arg, unsigned long flags)
{
	// flags: 0x00000A00, CLONE_VM: 0x00000100, CLONE_UNTRACED: 0x00800000,
	// fn: kernel_init, arg: NULL
	return do_fork(flags|CLONE_VM|CLONE_UNTRACED, (unsigned long)fn,
		(unsigned long)arg, NULL, NULL);
}

do_fork()

  • start_kernel()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starring()
  • kernel_thread()
  • call: kernel_thread()
  • do_fork()
  • call: do_fork()
// ARM10C 20160827
// flags: 0x00800B00, fn: kernel_init, arg: NULL, NULL, NULL
long do_fork(unsigned long clone_flags,
	      unsigned long stack_start,
	      unsigned long stack_size,
	      int __user *parent_tidptr,
	      int __user *child_tidptr)
{
	struct task_struct *p;
	int trace = 0;
	// trace: 0

	long nr;

	/*
	 * Determine whether and which event to report to ptracer.  When
	 * called from kernel_thread or CLONE_UNTRACED is explicitly
	 * requested, no event is reported; otherwise, report if the event
	 * for the type of forking is enabled.
	 */
	// clone_flags: 0x00800B00, CLONE_UNTRACED: 0x00800000
	if (!(clone_flags & CLONE_UNTRACED)) {
		if (clone_flags & CLONE_VFORK)
			trace = PTRACE_EVENT_VFORK;
		else if ((clone_flags & CSIGNAL) != SIGCHLD)
			trace = PTRACE_EVENT_CLONE;
		else
			trace = PTRACE_EVENT_FORK;

		if (likely(!ptrace_event_enabled(current, trace)))
			trace = 0;
	}

	// clone_flags: 0x00800B00, stack_start: kernel_init, stack_size: 0, child_tidptr: 0, trace: 0
	p = copy_process(clone_flags, stack_start, stack_size,
			 child_tidptr, NULL, trace);

do_fork()

  • start_kernel()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starring()
  • kernel_thread()
  • call: kernel_thread()
  • do_fork()
  • call: do_fork()
  • copy_process()
  • call: copy_process()
// ARM10C 20160827
// clone_flags: 0x00800B00, stack_start: kernel_init, stack_size: 0, child_tidptr: 0, NULL, trace: 0
static struct task_struct *copy_process(unsigned long clone_flags,
		unsigned long stack_start,
		unsigned long stack_size,
		int __user *child_tidptr,
		struct pid *pid,
		int trace)
{
	int retval;
	struct task_struct *p;

	// clone_flags: 0x00800B00, CLONE_NEWNS: 0x00020000, CLONE_FS: 0x00000200
	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
		return ERR_PTR(-EINVAL);

	// clone_flags: 0x00800B00, CLONE_NEWUSER: 0x10000000, CLONE_FS: 0x00000200
	if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
		return ERR_PTR(-EINVAL);

	/*
	 * Thread groups must share signals as well, and detached threads
	 * can only be started up within the thread group.
	 */
	// clone_flags: 0x00800B00, CLONE_THREAD: 0x00010000, CLONE_SIGHAND: 0x00000800
	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
		return ERR_PTR(-EINVAL);

	/*
	 * Shared signal handlers imply shared VM. By way of the above,
	 * thread groups also imply shared VM. Blocking this case allows
	 * for various simplifications in other code.
	 */
	// clone_flags: 0x00800B00, CLONE_SIGHAND: 0x00000800, CLONE_VM: 0x00000100
	if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
		return ERR_PTR(-EINVAL);

// 2016/08/27 종료
// 2016/09/03 시작

	/*
	 * Siblings of global init remain as zombies on exit since they are
	 * not reaped by their parent (swapper). To solve this and to avoid
	 * multi-rooted process trees, prevent global and container-inits
	 * from creating siblings.
	 */
	// clone_flags: 0x00800B00, CLONE_PARENT: 0x00008000, SIGNAL_UNKILLABLE: 0x00000040
	// current: &init_task, current->signal: &init_signals
	// current->signal->flags: (&init_signals)->flags: 0
	if ((clone_flags & CLONE_PARENT) &&
			current->signal->flags & SIGNAL_UNKILLABLE)
		return ERR_PTR(-EINVAL);

	/*
	 * If the new process will be in a different pid or user namespace
	 * do not allow it to share a thread group or signal handlers or
	 * parent with the forking task.
	 */
	// clone_flags: 0x00800B00, CLONE_SIGHAND: 0x00000800
	if (clone_flags & CLONE_SIGHAND) {
		// clone_flags: 0x00800B00, CLONE_NEWUSER: 0x10000000, CLONE_NEWPID: 0x20000000
		// current: &init_task, task_active_pid_ns(&init_task): &init_pid_ns,
		// current->nsproxy: (&init_task)->nsproxy: &init_nsproxy,
		// current->nsproxy->pid_ns_for_children: (&init_nsproxy)->pid_ns_for_children: &init_pid_ns
		if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
				(task_active_pid_ns(current) !=
				 current->nsproxy->pid_ns_for_children))
			return ERR_PTR(-EINVAL);
	}

	// clone_flags: 0x00800B00, security_task_create(0x00800B00): 0
	retval = security_task_create(clone_flags);
	// retval: 0

	// retval: 0
	if (retval)
		goto fork_out;

	// ENOMEM: 12
	retval = -ENOMEM;
	// retval: -12

	// current: &init_task
	// dup_task_struct(&init_task): kmem_cache#15-oX (struct task_struct)
	p = dup_task_struct(current);
	// p: kmem_cache#15-oX (struct task_struct)

	// dup_task_struct 에서 한일:
	// struct task_struct 만큼의 메모리를 할당 받음
	// kmem_cache#15-oX (struct task_struct)
	//
	// struct thread_info 를 구성 하기 위한 메모리를 할당 받음 (8K)
	// 할당 받은 page 2개의 메로리의 가상 주소
	//
	// 할당 받은 kmem_cache#15-oX (struct task_struct) 메모리에 init_task 값을 전부 할당함
	//
	// (kmem_cache#15-oX (struct task_struct))->stack: 할당 받은 page 2개의 메로리의 가상 주소
	//
	// 할당 받은 kmem_cache#15-oX (struct task_struct) 의 stack의 값을 init_task 의 stack 값에서 전부 복사함
	// 복사된 struct thread_info 의 task 주소값을 할당 받은 kmem_cache#15-oX (struct task_struct)로 변경함
	// *(할당 받은 page 2개의 메로리의 가상 주소): init_thread_info
	// ((struct thread_info *) 할당 받은 page 2개의 메로리의 가상 주소)->task: kmem_cache#15-oX (struct task_struct)
	//
	// (((struct thread_info *)(할당 받은 page 2개의 메로리의 가상 주소))->flags 의 1 bit 값을 clear 수행
	//
	// *((unsigned long *)(할당 받은 page 2개의 메로리의 가상 주소 + 1)): 0x57AC6E9D
	//
	// (&(kmem_cache#15-oX (struct task_struct))->usage)->counter: 2
	// (kmem_cache#15-oX (struct task_struct))->splice_pipe: NULL
	// (kmem_cache#15-oX (struct task_struct))->task_frag.page: NULL
	//
	// (&contig_page_data)->node_zones[0].vm_stat[16]: 1 을 더함
	// vmstat.c의 vm_stat[16] 전역 변수에도 1을 더함

	// p: kmem_cache#15-oX (struct task_struct)
	if (!p)
		goto fork_out;

	// p: kmem_cache#15-oX (struct task_struct)
	ftrace_graph_init_task(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	get_seccomp_filter(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	rt_mutex_init_task(p);

	// rt_mutex_init_task 한일:
	// &(kmem_cache#15-oX (struct task_struct))->pi_lock을 사용한 spinlock 초기화
	// &(kmem_cache#15-oX (struct task_struct))->pi_waiters 리스트 초기화
	// (kmem_cache#15-oX (struct task_struct))->pi_blocked_on: NULL

#ifdef CONFIG_PROVE_LOCKING // CONFIG_PROVE_LOCKING=n
	DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
	// EAGAIN: 11
	retval = -EAGAIN;
	// retval: -11

	// p: kmem_cache#15-oX (struct task_struct)
	// p->real_cred: (kmem_cache#15-oX (struct task_struct))->real_cred: &init_cred,
	// p->real_cred->user: (&init_cred)->user: &root_user,
	// &p->real_cred->user->processes: &(&root_user)->processes, atomic_read(&(&root_user)->processes): 1
	// RLIMIT_NPROC: 6, task_rlimit(kmem_cache#15-oX (struct task_struct), 6): 0
	if (atomic_read(&p->real_cred->user->processes) >=
			task_rlimit(p, RLIMIT_NPROC)) {
		// p->real_cred->user: (&init_cred)->user: &root_user, INIT_USER: (&root_user)
		// CAP_SYS_RESOURCE: 24, capable(24): true, CAP_SYS_ADMIN: 21, capable(21): true
		if (p->real_cred->user != INIT_USER &&
		    !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
			goto bad_fork_free;

		// capable 에서 한일:
		// (&init_task)->flags: 0x00200100
	}

	// current->flags: (&init_task)->flags: 0x00200100, PF_NPROC_EXCEEDED: 0x00001000
	current->flags &= ~PF_NPROC_EXCEEDED;
	// current->flags: (&init_task)->flags: 0x00200100

	// retval: -11, p: kmem_cache#15-oX (struct task_struct), clone_flags: 0x00800B00
	// copy_creds(kmem_cache#15-oX (struct task_struct), 0x00800B00): 0
	retval = copy_creds(p, clone_flags);
	// retval: 0

	// copy_creds 에서 한일:
	// struct cred 만큼의 메모리를 할당 받음
	// kmem_cache#16-oX (struct cred)
	//
	// kmem_cache#16-oX (struct cred) 에 init_cred 에 있는 맴버값 전부를 복사함
	// (&(kmem_cache#16-oX (struct cred))->usage)->counter: 1
	// (&(&init_groups)->usage)->counter: 3
	// (&(&root_user)->__count)->counter: 2
	// (&(&root_user)->processes)->counter: 2
	//
	// (&(kmem_cache#16-oX (struct cred))->usage)->counter: 2
	//
	// (kmem_cache#15-oX (struct task_struct))->cred: kmem_cache#16-oX (struct cred)
	// (kmem_cache#15-oX (struct task_struct))->real_cred: kmem_cache#16-oX (struct cred)

	// retval: 0
	if (retval < 0)
		goto bad_fork_free;

	/*
	 * If multiple threads are within copy_process(), then this check
	 * triggers too late. This doesn't hurt, the check is only there
	 * to stop root fork bombs.
	 */
	// EAGAIN: 11
	retval = -EAGAIN;
	// retval: -11

	// nr_threads: 0, max_threads: 총 free된 page 수 / 16
	if (nr_threads >= max_threads)
		goto bad_fork_cleanup_count;

	// p: kmem_cache#15-oX (struct task_struct),
	// task_thread_info(kmem_cache#15-oX (struct task_struct)):
	// (kmem_cache#15-oX (struct task_struct))->stack: 할당 받은 page 2개의 메로리의 가상 주소,
	// task_thread_info(kmem_cache#15-oX (struct task_struct)->exec_domain:
	// ((struct thread_info *) 할당 받은 page 2개의 메로리의 가상 주소)->exec_domain: &default_exec_domain,
	// task_thread_info(kmem_cache#15-oX (struct task_struct)->exec_domain->module:
	// (&default_exec_domain)->module: NULL,
	// try_module_get(NULL): true
	if (!try_module_get(task_thread_info(p)->exec_domain->module))
		goto bad_fork_cleanup_count;

	// p->did_exec: (kmem_cache#15-oX (struct task_struct))->did_exec
	p->did_exec = 0;
	// p->did_exec: (kmem_cache#15-oX (struct task_struct))->did_exec: 0

	// p: kmem_cache#15-oX (struct task_struct)
	delayacct_tsk_init(p);	/* Must remain after dup_task_struct() */ // null function

	// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
	copy_flags(clone_flags, p);

	// copy_flags 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->flags: 0x00200040

	// &p->children: &(kmem_cache#15-oX (struct task_struct))->children
	INIT_LIST_HEAD(&p->children);

	// INIT_LIST_HEAD 에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->children)->next: &(kmem_cache#15-oX (struct task_struct))->children
	// (&(kmem_cache#15-oX (struct task_struct))->children)->prev: &(kmem_cache#15-oX (struct task_struct))->children

	// &p->sibling: &(kmem_cache#15-oX (struct task_struct))->sibling
	INIT_LIST_HEAD(&p->sibling);

	// INIT_LIST_HEAD 에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->sibling)->next: &(kmem_cache#15-oX (struct task_struct))->sibling
	// (&(kmem_cache#15-oX (struct task_struct))->sibling)->prev: &(kmem_cache#15-oX (struct task_struct))->sibling

	// p: kmem_cache#15-oX (struct task_struct)
	rcu_copy_process(p);

	// rcu_copy_process 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->rcu_read_lock_nesting: 0
	// (kmem_cache#15-oX (struct task_struct))->rcu_read_unlock_special: 0
	// (kmem_cache#15-oX (struct task_struct))->rcu_blocked_node: NULL
	// (&(kmem_cache#15-oX (struct task_struct))->rcu_node_entry)->next: &(kmem_cache#15-oX (struct task_struct))->rcu_node_entry
	// (&(kmem_cache#15-oX (struct task_struct))->rcu_node_entry)->prev: &(kmem_cache#15-oX (struct task_struct))->rcu_node_entry

	// p->vfork_done: (kmem_cache#15-oX (struct task_struct))->vfork_done
	p->vfork_done = NULL;
	// p->vfork_done: (kmem_cache#15-oX (struct task_struct))->vfork_done: NULL

	// &p->alloc_lock: &(kmem_cache#15-oX (struct task_struct))->alloc_lock
	spin_lock_init(&p->alloc_lock);

	// spin_lock_init에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->raw_lock: { { 0 } }
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->magic: 0xdead4ead
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->owner: 0xffffffff
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->owner_cpu: 0xffffffff

	// &p->pending: &(kmem_cache#15-oX (struct task_struct))->pending
	init_sigpending(&p->pending);

	// init_sigpending 에서 한일:
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->signal)->sig[0]: 0
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->signal)->sig[1]: 0
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->list)->next: &(&(kmem_cache#15-oX (struct task_struct))->pending)->list
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->list)->prev: &(&(kmem_cache#15-oX (struct task_struct))->pending)->list

	// p->utime: (kmem_cache#15-oX (struct task_struct))->utime,
	// p->stime: (kmem_cache#15-oX (struct task_struct))->stime,
	// p->gtime: (kmem_cache#15-oX (struct task_struct))->gtime
	p->utime = p->stime = p->gtime = 0;
	// p->utime: (kmem_cache#15-oX (struct task_struct))->utime: 0
	// p->stime: (kmem_cache#15-oX (struct task_struct))->stime: 0
	// p->gtime: (kmem_cache#15-oX (struct task_struct))->gtime: 0

	// p->utimescaled: (kmem_cache#15-oX (struct task_struct))->utimescaled,
	// p->stimescaled: (kmem_cache#15-oX (struct task_struct))->stimescaled
	p->utimescaled = p->stimescaled = 0;
	// p->utimescaled: (kmem_cache#15-oX (struct task_struct))->utimescaled: 0
	// p->stimescaled: (kmem_cache#15-oX (struct task_struct))->stimescaled: 0

#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE // CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=n
	p->prev_cputime.utime = p->prev_cputime.stime = 0;
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN // CONFIG_VIRT_CPU_ACCOUNTING_GEN=n
	seqlock_init(&p->vtime_seqlock);
	p->vtime_snap = 0;
	p->vtime_snap_whence = VTIME_SLEEPING;
#endif

#if defined(SPLIT_RSS_COUNTING)
	// &p->rss_stat: &(kmem_cache#15-oX (struct task_struct))->rss_stat
	memset(&p->rss_stat, 0, sizeof(p->rss_stat));

	// memset 에서 한일:
	// &(kmem_cache#15-oX (struct task_struct))->rss_stat 값을 0 으로 초기화 수행
#endif

	// p->default_timer_slack_ns: (kmem_cache#15-oX (struct task_struct))->default_timer_slack_ns,
	// current->timer_slack_ns: (&init_task)->timer_slack_ns: 50000
	p->default_timer_slack_ns = current->timer_slack_ns;
	// p->default_timer_slack_ns: (kmem_cache#15-oX (struct task_struct))->default_timer_slack_ns: 50000

	// p->ioac: (kmem_cache#15-oX (struct task_struct))->ioac
	task_io_accounting_init(&p->ioac); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	acct_clear_integrals(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	posix_cpu_timers_init(p);

	// posix_cpu_timers_init 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.prof_exp: 0
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.virt_exp: 0
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.sched_exp: 0
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[0])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[0]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[0])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[0]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[1])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[1]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[1])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[1]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[2])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[2]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[2])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[2]

	// &p->start_time: &(kmem_cache#15-oX (struct task_struct))->start_time
	do_posix_clock_monotonic_gettime(&p->start_time);

	// do_posix_clock_monotonic_gettime 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->start_time 에 현재 시간 값을 가져옴
	//
	// (&(kmem_cache#15-oX (struct task_struct))->start_time)->tv_sec: 현재의 sec 값 + 현재의 nsec 값 / 1000000000L
	// (&(kmem_cache#15-oX (struct task_struct))->start_time)->tv_nsec: 현재의 nsec 값 % 1000000000L

	// p->real_start_time: (kmem_cache#15-oX (struct task_struct))->real_start_time,
	// p->start_time: (kmem_cache#15-oX (struct task_struct))->start_time
	p->real_start_time = p->start_time;
	// (&(kmem_cache#15-oX (struct task_struct))->real_start_time)->tv_sec: 현재의 sec 값 + 현재의 nsec 값 / 1000000000L
	// (&(kmem_cache#15-oX (struct task_struct))->real_start_time)->tv_nsec: 현재의 nsec 값 % 1000000000L

	// &p->real_start_time: &(kmem_cache#15-oX (struct task_struct))->real_start_time
	monotonic_to_bootbased(&p->real_start_time);

	// monotonic_to_bootbased 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->real_start_time.tv_sec: normalized 된 sec 값
	// (kmem_cache#15-oX (struct task_struct))->real_start_time.tv_nsec: normalized 된 nsec 값

	// p->io_context: (kmem_cache#15-oX (struct task_struct))->io_context
	p->io_context = NULL;
	// p->io_context: (kmem_cache#15-oX (struct task_struct))->io_context: NULL

	// p->audit_context: (kmem_cache#15-oX (struct task_struct))->audit_context
	p->audit_context = NULL;
	// p->audit_context: (kmem_cache#15-oX (struct task_struct))->audit_context: NULL

	if (clone_flags & CLONE_THREAD)
		threadgroup_change_begin(current);
	cgroup_fork(p);

copy_process()

  • start_kernel()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starting()
  • kernel_thread()
  • call: kernel_thread()
  • do_fork()
  • call: do_fork()
  • copy_process()
// ARM10C 20160827
// clone_flags: 0x00800B00, stack_start: kernel_init, stack_size: 0, child_tidptr: 0, NULL, trace: 0
static struct task_struct *copy_process(unsigned long clone_flags,
		unsigned long stack_start,
		unsigned long stack_size,
		int __user *child_tidptr,
		struct pid *pid,
		int trace)
{

	int retval;
	struct task_struct *p;

	// clone_flags: 0x00800B00, CLONE_NEWNS: 0x00020000, CLONE_FS: 0x00000200
	if ((clone_flags & (CLONE_NEWNS|CLONE_FS)) == (CLONE_NEWNS|CLONE_FS))
		return ERR_PTR(-EINVAL);

	// clone_flags: 0x00800B00, CLONE_NEWUSER: 0x10000000, CLONE_FS: 0x00000200
	if ((clone_flags & (CLONE_NEWUSER|CLONE_FS)) == (CLONE_NEWUSER|CLONE_FS))
		return ERR_PTR(-EINVAL);

	/*
	 * Thread groups must share signals as well, and detached threads
	 * can only be started up within the thread group.
	 */
	// clone_flags: 0x00800B00, CLONE_THREAD: 0x00010000, CLONE_SIGHAND: 0x00000800
	if ((clone_flags & CLONE_THREAD) && !(clone_flags & CLONE_SIGHAND))
		return ERR_PTR(-EINVAL);

	/*
	 * Shared signal handlers imply shared VM. By way of the above,
	 * thread groups also imply shared VM. Blocking this case allows
	 * for various simplifications in other code.
	 */
	// clone_flags: 0x00800B00, CLONE_SIGHAND: 0x00000800, CLONE_VM: 0x00000100
	if ((clone_flags & CLONE_SIGHAND) && !(clone_flags & CLONE_VM))
		return ERR_PTR(-EINVAL);

// 2016/08/27 종료
// 2016/09/03 시작

	/*
	 * Siblings of global init remain as zombies on exit since they are
	 * not reaped by their parent (swapper). To solve this and to avoid
	 * multi-rooted process trees, prevent global and container-inits
	 * from creating siblings.
	 */
	// clone_flags: 0x00800B00, CLONE_PARENT: 0x00008000, SIGNAL_UNKILLABLE: 0x00000040
	// current: &init_task, current->signal: &init_signals
	// current->signal->flags: (&init_signals)->flags: 0
	if ((clone_flags & CLONE_PARENT) &&
			current->signal->flags & SIGNAL_UNKILLABLE)
		return ERR_PTR(-EINVAL);

	/*
	 * If the new process will be in a different pid or user namespace
	 * do not allow it to share a thread group or signal handlers or
	 * parent with the forking task.
	 */
	// clone_flags: 0x00800B00, CLONE_SIGHAND: 0x00000800
	if (clone_flags & CLONE_SIGHAND) {
		// clone_flags: 0x00800B00, CLONE_NEWUSER: 0x10000000, CLONE_NEWPID: 0x20000000
		// current: &init_task, task_active_pid_ns(&init_task): &init_pid_ns,
		// current->nsproxy: (&init_task)->nsproxy: &init_nsproxy,
		// current->nsproxy->pid_ns_for_children: (&init_nsproxy)->pid_ns_for_children: &init_pid_ns
		if ((clone_flags & (CLONE_NEWUSER | CLONE_NEWPID)) ||
				(task_active_pid_ns(current) !=
				 current->nsproxy->pid_ns_for_children))
			return ERR_PTR(-EINVAL);
	}

	// clone_flags: 0x00800B00, security_task_create(0x00800B00): 0
	retval = security_task_create(clone_flags);
	// retval: 0

	// retval: 0
	if (retval)
		goto fork_out;

	// ENOMEM: 12
	retval = -ENOMEM;
	// retval: -12

	// current: &init_task
	// dup_task_struct(&init_task): kmem_cache#15-oX (struct task_struct)
	p = dup_task_struct(current);
	// p: kmem_cache#15-oX (struct task_struct)

	// dup_task_struct 에서 한일:
	// struct task_struct 만큼의 메모리를 할당 받음
	// kmem_cache#15-oX (struct task_struct)
	//
	// struct thread_info 를 구성 하기 위한 메모리를 할당 받음 (8K)
	// 할당 받은 page 2개의 메로리의 가상 주소
	//
	// 할당 받은 kmem_cache#15-oX (struct task_struct) 메모리에 init_task 값을 전부 할당함
	//
	// (kmem_cache#15-oX (struct task_struct))->stack: 할당 받은 page 2개의 메로리의 가상 주소
	//
	// 할당 받은 kmem_cache#15-oX (struct task_struct) 의 stack의 값을 init_task 의 stack 값에서 전부 복사함
	// 복사된 struct thread_info 의 task 주소값을 할당 받은 kmem_cache#15-oX (struct task_struct)로 변경함
	// *(할당 받은 page 2개의 메로리의 가상 주소): init_thread_info
	// ((struct thread_info *) 할당 받은 page 2개의 메로리의 가상 주소)->task: kmem_cache#15-oX (struct task_struct)
	//
	// (((struct thread_info *)(할당 받은 page 2개의 메로리의 가상 주소))->flags 의 1 bit 값을 clear 수행
	//
	// *((unsigned long *)(할당 받은 page 2개의 메로리의 가상 주소 + 1)): 0x57AC6E9D
	//
	// (&(kmem_cache#15-oX (struct task_struct))->usage)->counter: 2
	// (kmem_cache#15-oX (struct task_struct))->splice_pipe: NULL
	// (kmem_cache#15-oX (struct task_struct))->task_frag.page: NULL
	//
	// (&contig_page_data)->node_zones[0].vm_stat[16]: 1 을 더함
	// vmstat.c의 vm_stat[16] 전역 변수에도 1을 더함

	// p: kmem_cache#15-oX (struct task_struct)
	if (!p)
		goto fork_out;

	// p: kmem_cache#15-oX (struct task_struct)
	ftrace_graph_init_task(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	get_seccomp_filter(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	rt_mutex_init_task(p);

	// rt_mutex_init_task 한일:
	// &(kmem_cache#15-oX (struct task_struct))->pi_lock을 사용한 spinlock 초기화
	// &(kmem_cache#15-oX (struct task_struct))->pi_waiters 리스트 초기화
	// (kmem_cache#15-oX (struct task_struct))->pi_blocked_on: NULL

#ifdef CONFIG_PROVE_LOCKING // CONFIG_PROVE_LOCKING=n
	DEBUG_LOCKS_WARN_ON(!p->hardirqs_enabled);
	DEBUG_LOCKS_WARN_ON(!p->softirqs_enabled);
#endif
	// EAGAIN: 11
	retval = -EAGAIN;
	// retval: -11

	// p: kmem_cache#15-oX (struct task_struct)
	// p->real_cred: (kmem_cache#15-oX (struct task_struct))->real_cred: &init_cred,
	// p->real_cred->user: (&init_cred)->user: &root_user,
	// &p->real_cred->user->processes: &(&root_user)->processes, atomic_read(&(&root_user)->processes): 1
	// RLIMIT_NPROC: 6, task_rlimit(kmem_cache#15-oX (struct task_struct), 6): 0
	if (atomic_read(&p->real_cred->user->processes) >=
			task_rlimit(p, RLIMIT_NPROC)) {
		// p->real_cred->user: (&init_cred)->user: &root_user, INIT_USER: (&root_user)
		// CAP_SYS_RESOURCE: 24, capable(24): true, CAP_SYS_ADMIN: 21, capable(21): true
		if (p->real_cred->user != INIT_USER &&
		    !capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN))
			goto bad_fork_free;

		// capable 에서 한일:
		// (&init_task)->flags: 0x00200100
	}

	// current->flags: (&init_task)->flags: 0x00200100, PF_NPROC_EXCEEDED: 0x00001000
	current->flags &= ~PF_NPROC_EXCEEDED;
	// current->flags: (&init_task)->flags: 0x00200100

	// retval: -11, p: kmem_cache#15-oX (struct task_struct), clone_flags: 0x00800B00
	// copy_creds(kmem_cache#15-oX (struct task_struct), 0x00800B00): 0
	retval = copy_creds(p, clone_flags);
	// retval: 0

	// copy_creds 에서 한일:
	// struct cred 만큼의 메모리를 할당 받음
	// kmem_cache#16-oX (struct cred)
	//
	// kmem_cache#16-oX (struct cred) 에 init_cred 에 있는 맴버값 전부를 복사함
	// (&(kmem_cache#16-oX (struct cred))->usage)->counter: 1
	// (&(&init_groups)->usage)->counter: 3
	// (&(&root_user)->__count)->counter: 2
	// (&(&root_user)->processes)->counter: 2
	//
	// (&(kmem_cache#16-oX (struct cred))->usage)->counter: 2
	//
	// (kmem_cache#15-oX (struct task_struct))->cred: kmem_cache#16-oX (struct cred)
	// (kmem_cache#15-oX (struct task_struct))->real_cred: kmem_cache#16-oX (struct cred)

	// retval: 0
	if (retval < 0)
		goto bad_fork_free;

	/*
	 * If multiple threads are within copy_process(), then this check
	 * triggers too late. This doesn't hurt, the check is only there
	 * to stop root fork bombs.
	 */
	// EAGAIN: 11
	retval = -EAGAIN;
	// retval: -11

	// nr_threads: 0, max_threads: 총 free된 page 수 / 16
	if (nr_threads >= max_threads)
		goto bad_fork_cleanup_count;

	// p: kmem_cache#15-oX (struct task_struct),
	// task_thread_info(kmem_cache#15-oX (struct task_struct)):
	// (kmem_cache#15-oX (struct task_struct))->stack: 할당 받은 page 2개의 메로리의 가상 주소,
	// task_thread_info(kmem_cache#15-oX (struct task_struct)->exec_domain:
	// ((struct thread_info *) 할당 받은 page 2개의 메로리의 가상 주소)->exec_domain: &default_exec_domain,
	// task_thread_info(kmem_cache#15-oX (struct task_struct)->exec_domain->module:
	// (&default_exec_domain)->module: NULL,
	// try_module_get(NULL): true
	if (!try_module_get(task_thread_info(p)->exec_domain->module))
		goto bad_fork_cleanup_count;

	// p->did_exec: (kmem_cache#15-oX (struct task_struct))->did_exec
	p->did_exec = 0;
	// p->did_exec: (kmem_cache#15-oX (struct task_struct))->did_exec: 0

	// p: kmem_cache#15-oX (struct task_struct)
	delayacct_tsk_init(p);	/* Must remain after dup_task_struct() */ // null function

	// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
	copy_flags(clone_flags, p);

	// copy_flags 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->flags: 0x00200040

	// &p->children: &(kmem_cache#15-oX (struct task_struct))->children
	INIT_LIST_HEAD(&p->children);

	// INIT_LIST_HEAD 에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->children)->next: &(kmem_cache#15-oX (struct task_struct))->children
	// (&(kmem_cache#15-oX (struct task_struct))->children)->prev: &(kmem_cache#15-oX (struct task_struct))->children

	// &p->sibling: &(kmem_cache#15-oX (struct task_struct))->sibling
	INIT_LIST_HEAD(&p->sibling);

	// INIT_LIST_HEAD 에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->sibling)->next: &(kmem_cache#15-oX (struct task_struct))->sibling
	// (&(kmem_cache#15-oX (struct task_struct))->sibling)->prev: &(kmem_cache#15-oX (struct task_struct))->sibling

	// p: kmem_cache#15-oX (struct task_struct)
	rcu_copy_process(p);

	// rcu_copy_process 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->rcu_read_lock_nesting: 0
	// (kmem_cache#15-oX (struct task_struct))->rcu_read_unlock_special: 0
	// (kmem_cache#15-oX (struct task_struct))->rcu_blocked_node: NULL
	// (&(kmem_cache#15-oX (struct task_struct))->rcu_node_entry)->next: &(kmem_cache#15-oX (struct task_struct))->rcu_node_entry
	// (&(kmem_cache#15-oX (struct task_struct))->rcu_node_entry)->prev: &(kmem_cache#15-oX (struct task_struct))->rcu_node_entry

	// p->vfork_done: (kmem_cache#15-oX (struct task_struct))->vfork_done
	p->vfork_done = NULL;
	// p->vfork_done: (kmem_cache#15-oX (struct task_struct))->vfork_done: NULL

	// &p->alloc_lock: &(kmem_cache#15-oX (struct task_struct))->alloc_lock
	spin_lock_init(&p->alloc_lock);

	// spin_lock_init에서 한일:
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->raw_lock: { { 0 } }
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->magic: 0xdead4ead
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->owner: 0xffffffff
	// (&(kmem_cache#15-oX (struct task_struct))->alloc_lock)->owner_cpu: 0xffffffff

	// &p->pending: &(kmem_cache#15-oX (struct task_struct))->pending
	init_sigpending(&p->pending);

	// init_sigpending 에서 한일:
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->signal)->sig[0]: 0
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->signal)->sig[1]: 0
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->list)->next: &(&(kmem_cache#15-oX (struct task_struct))->pending)->list
	// (&(&(kmem_cache#15-oX (struct task_struct))->pending)->list)->prev: &(&(kmem_cache#15-oX (struct task_struct))->pending)->list

	// p->utime: (kmem_cache#15-oX (struct task_struct))->utime,
	// p->stime: (kmem_cache#15-oX (struct task_struct))->stime,
	// p->gtime: (kmem_cache#15-oX (struct task_struct))->gtime
	p->utime = p->stime = p->gtime = 0;
	// p->utime: (kmem_cache#15-oX (struct task_struct))->utime: 0
	// p->stime: (kmem_cache#15-oX (struct task_struct))->stime: 0
	// p->gtime: (kmem_cache#15-oX (struct task_struct))->gtime: 0

	// p->utimescaled: (kmem_cache#15-oX (struct task_struct))->utimescaled,
	// p->stimescaled: (kmem_cache#15-oX (struct task_struct))->stimescaled
	p->utimescaled = p->stimescaled = 0;
	// p->utimescaled: (kmem_cache#15-oX (struct task_struct))->utimescaled: 0
	// p->stimescaled: (kmem_cache#15-oX (struct task_struct))->stimescaled: 0

#ifndef CONFIG_VIRT_CPU_ACCOUNTING_NATIVE // CONFIG_VIRT_CPU_ACCOUNTING_NATIVE=n
	p->prev_cputime.utime = p->prev_cputime.stime = 0;
#endif
#ifdef CONFIG_VIRT_CPU_ACCOUNTING_GEN // CONFIG_VIRT_CPU_ACCOUNTING_GEN=n
	seqlock_init(&p->vtime_seqlock);
	p->vtime_snap = 0;
	p->vtime_snap_whence = VTIME_SLEEPING;
#endif

#if defined(SPLIT_RSS_COUNTING)
	// &p->rss_stat: &(kmem_cache#15-oX (struct task_struct))->rss_stat
	memset(&p->rss_stat, 0, sizeof(p->rss_stat));

	// memset 에서 한일:
	// &(kmem_cache#15-oX (struct task_struct))->rss_stat 값을 0 으로 초기화 수행
#endif

	// p->default_timer_slack_ns: (kmem_cache#15-oX (struct task_struct))->default_timer_slack_ns,
	// current->timer_slack_ns: (&init_task)->timer_slack_ns: 50000
	p->default_timer_slack_ns = current->timer_slack_ns;
	// p->default_timer_slack_ns: (kmem_cache#15-oX (struct task_struct))->default_timer_slack_ns: 50000

	// p->ioac: (kmem_cache#15-oX (struct task_struct))->ioac
	task_io_accounting_init(&p->ioac); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	acct_clear_integrals(p); // null function

	// p: kmem_cache#15-oX (struct task_struct)
	posix_cpu_timers_init(p);

	// posix_cpu_timers_init 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.prof_exp: 0
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.virt_exp: 0
	// (kmem_cache#15-oX (struct task_struct))->cputime_expires.sched_exp: 0
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[0])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[0]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[0])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[0]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[1])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[1]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[1])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[1]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[2])->next: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[2]
	// (&(kmem_cache#15-oX (struct task_struct))->cpu_timers[2])->prev: &(kmem_cache#15-oX (struct task_struct))->cpu_timers[2]

	// &p->start_time: &(kmem_cache#15-oX (struct task_struct))->start_time
	do_posix_clock_monotonic_gettime(&p->start_time);

	// do_posix_clock_monotonic_gettime 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->start_time 에 현재 시간 값을 가져옴
	//
	// (&(kmem_cache#15-oX (struct task_struct))->start_time)->tv_sec: 현재의 sec 값 + 현재의 nsec 값 / 1000000000L
	// (&(kmem_cache#15-oX (struct task_struct))->start_time)->tv_nsec: 현재의 nsec 값 % 1000000000L

	// p->real_start_time: (kmem_cache#15-oX (struct task_struct))->real_start_time,
	// p->start_time: (kmem_cache#15-oX (struct task_struct))->start_time
	p->real_start_time = p->start_time;
	// (&(kmem_cache#15-oX (struct task_struct))->real_start_time)->tv_sec: 현재의 sec 값 + 현재의 nsec 값 / 1000000000L
	// (&(kmem_cache#15-oX (struct task_struct))->real_start_time)->tv_nsec: 현재의 nsec 값 % 1000000000L

	// &p->real_start_time: &(kmem_cache#15-oX (struct task_struct))->real_start_time
	monotonic_to_bootbased(&p->real_start_time);

	// monotonic_to_bootbased 에서 한일:
	// (kmem_cache#15-oX (struct task_struct))->real_start_time.tv_sec: normalized 된 sec 값
	// (kmem_cache#15-oX (struct task_struct))->real_start_time.tv_nsec: normalized 된 nsec 값

	// p->io_context: (kmem_cache#15-oX (struct task_struct))->io_context
	p->io_context = NULL;
	// p->io_context: (kmem_cache#15-oX (struct task_struct))->io_context: NULL

	// p->audit_context: (kmem_cache#15-oX (struct task_struct))->audit_context
	p->audit_context = NULL;
	// p->audit_context: (kmem_cache#15-oX (struct task_struct))->audit_context: NULL

// 2016/09/10 종료
// 2016/10/08 시작

	// clone_flags: 0x00800B00, CLONE_THREAD: 0x00010000
	if (clone_flags & CLONE_THREAD)
		threadgroup_change_begin(current);

	// p: kmem_cache#15-oX (struct task_struct)
	cgroup_fork(p);

	// cgroup_fork 에서 한일:
	// rcu reference의 값 (&init_task)->cgroups 이 유요한지 체크하고 그 값을 리턴함
	// ((&init_task)->cgroups)->refcount: 1
	// (kmem_cache#15-oX (struct task_struct))->cgroups: (&init_task)->cgroups
	//
	// (&(kmem_cache#15-oX (struct task_struct))->cg_list)->next: &(kmem_cache#15-oX (struct task_struct))->cg_list
	// (&(kmem_cache#15-oX (struct task_struct))->cg_list)->prev: &(kmem_cache#15-oX (struct task_struct))->cg_list

#ifdef CONFIG_NUMA // CONFIG_NUMA=n
	p->mempolicy = mpol_dup(p->mempolicy);
	if (IS_ERR(p->mempolicy)) {
		retval = PTR_ERR(p->mempolicy);
		p->mempolicy = NULL;
		goto bad_fork_cleanup_cgroup;
	}
	mpol_fix_fork_child_flag(p);
#endif
#ifdef CONFIG_CPUSETS // CONFIG_CPUSETS=n
	p->cpuset_mem_spread_rotor = NUMA_NO_NODE;
	p->cpuset_slab_spread_rotor = NUMA_NO_NODE;
	seqcount_init(&p->mems_allowed_seq);
#endif
#ifdef CONFIG_TRACE_IRQFLAGS // CONFIG_TRACE_IRQFLAGS=n
	p->irq_events = 0;
	p->hardirqs_enabled = 0;
	p->hardirq_enable_ip = 0;
	p->hardirq_enable_event = 0;
	p->hardirq_disable_ip = _THIS_IP_;
	p->hardirq_disable_event = 0;
	p->softirqs_enabled = 1;
	p->softirq_enable_ip = _THIS_IP_;
	p->softirq_enable_event = 0;
	p->softirq_disable_ip = 0;
	p->softirq_disable_event = 0;
	p->hardirq_context = 0;
	p->softirq_context = 0;
#endif
#ifdef CONFIG_LOCKDEP // CONFIG_LOCKDEP=n
	p->lockdep_depth = 0; /* no locks held yet */
	p->curr_chain_key = 0;
	p->lockdep_recursion = 0;
#endif

#ifdef CONFIG_DEBUG_MUTEXES // CONFIG_DEBUG_MUTEXES=y
	// p->blocked_on: (kmem_cache#15-oX (struct task_struct))->blocked_on
	p->blocked_on = NULL; /* not blocked yet */
	// p->blocked_on: (kmem_cache#15-oX (struct task_struct))->blocked_on: NULL
#endif
#ifdef CONFIG_MEMCG // CONFIG_MEMCG=n
	p->memcg_batch.do_batch = 0;
	p->memcg_batch.memcg = NULL;
#endif
#ifdef CONFIG_BCACHE // CONFIG_BCACHE=n
	p->sequential_io	= 0;
	p->sequential_io_avg	= 0;
#endif

	/* Perform scheduler related setup. Assign this task to a CPU. */
	// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
	sched_fork(clone_flags, p);

sched_fork()

  • start_kernel()
  • rest_init()
  • call: rest_init()
  • rcu_scheduler_starting()
  • kernel_thread()
  • call: kernel_thread()
  • do_fork()
  • call: do_fork()
  • copy_process()
  • call: copy_process()
  • security_task_create()
  • dup_task_struct()
  • ftrace_graph_init_task§; // null function
  • get_seccomp_filter§; // null function
  • rt_mutex_init_task§;
  • copy_creds(p, clone_flags);
  • try_module_get()
  • delayacct_tsk_init§
  • copy_flags()
  • INIT_LIST_HEAD(&p->children);
  • INIT_LIST_HEAD(&p->sibling);
  • rcu_copy_process§;
  • spin_lock_init(&p->alloc_lock);
  • init_sigpending(&p->pending);
  • memset(&p->rss_stat, 0, sizeof(p->rss_stat));
  • task_io_accounting_init(&p->ioac); // null function
  • acct_clear_integrals§; // null function
  • posix_cpu_timers_init§;
  • do_posix_clock_monotonic_gettime(&p->start_time);
  • monotonic_to_bootbased(&p->real_start_time);
  • cgroup_fork§;
  • sched_fork(clone_flags, p);
// ARM10C 20161008
// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
void sched_fork(unsigned long clone_flags, struct task_struct *p)
{
	unsigned long flags;

	// get_cpu(): 0
	int cpu = get_cpu();
	// cpu: 0

	// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
	__sched_fork(clone_flags, p);

	// __sched_fork에서 한일:
	// (&kmem_cache#15-oX (struct task_struct))->on_rq: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.on_rq: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.exec_start: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.sum_exec_runtime: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.prev_sum_exec_runtime: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.nr_migrations: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.vruntime: 0
	// &(&kmem_cache#15-oX (struct task_struct))->se.group_node의 리스트 초기화
	// &(&kmem_cache#15-oX (struct task_struct))->rt.run_list의 리스트 초기화

	/*
	 * We mark the process as running here. This guarantees that
	 * nobody will actually run it, and a signal or other external
	 * event cannot wake it up and insert it on the runqueue either.
	 */

	// p->state: (kmem_cache#15-oX (struct task_struct))->state, TASK_RUNNING: 0
	p->state = TASK_RUNNING;
	// p->state: (kmem_cache#15-oX (struct task_struct))->state: 0

	/*
	 * Make sure we do not leak PI boosting priority to the child.
	 */
	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio,
	// current: &init_task, current->normal_prio: (&init_task)->normal_prio: 120
	p->prio = current->normal_prio;
	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio: 120

	/*
	 * Revert to default priority/policy on fork if requested.
	 */
	// p->>sched_reset_on_fork: (kmem_cache#15-oX (struct task_struct))->sched_reset_on_fork: 0
	if (unlikely(p->sched_reset_on_fork)) {
		if (task_has_rt_policy(p)) {
			p->policy = SCHED_NORMAL;
			p->static_prio = NICE_TO_PRIO(0);
			p->rt_priority = 0;
		} else if (PRIO_TO_NICE(p->static_prio) < 0)
			p->static_prio = NICE_TO_PRIO(0);

		p->prio = p->normal_prio = __normal_prio(p);
		set_load_weight(p);

		/*
		 * We don't need the reset flag anymore after the fork. It has
		 * fulfilled its duty:
		 */
		p->sched_reset_on_fork = 0;
	}

	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio: 120, rt_prio(120): 0
	if (!rt_prio(p->prio))
		// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class
		p->sched_class = &fair_sched_class;
		// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class: &fair_sched_class

// 2016/10/15 종료

	// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class: &fair_sched_class,
	// p->sched_class->task_fork: (&fair_sched_class)->task_fork: task_fork_fair
	if (p->sched_class->task_fork)
		// p->sched_class->task_fork: (&fair_sched_class)->task_fork: task_fork_fair,
		// p: kmem_cache#15-oX (struct task_struct),
		// task_fork_fair(kmem_cache#15-oX (struct task_struct))
		p->sched_class->task_fork(p);

		// task_fork_fair 에서 한일:

	/*
	 * The child is not yet in the pid-hash so no cgroup attach races,
	 * and the cgroup is pinned to this child due to cgroup_fork()
	 * is ran before sched_fork().
	 *
	 * Silence PROVE_RCU.
	 */
	raw_spin_lock_irqsave(&p->pi_lock, flags);
	set_task_cpu(p, cpu);

set_task_cpu()

void set_task_cpu(struct task_struct *p, unsigned int new_cpu)
{
#ifdef CONFIG_SCHED_DEBUG
	/*
	 * We should never call set_task_cpu() on a blocked task,
	 * ttwu() will sort out the placement.
	 */
	WARN_ON_ONCE(p->state != TASK_RUNNING && p->state != TASK_WAKING &&
			!(task_preempt_count(p) & PREEMPT_ACTIVE));

#ifdef CONFIG_LOCKDEP
	/*
	 * The caller should hold either p->pi_lock or rq->lock, when changing
	 * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks.
	 *
	 * sched_move_task() holds both and thus holding either pins the cgroup,
	 * see task_group().
	 *
	 * Furthermore, all task_rq users should acquire both locks, see
	 * task_rq_lock().
	 */
	WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) ||
				      lockdep_is_held(&task_rq(p)->lock)));
#endif
#endif

	trace_sched_migrate_task(p, new_cpu);

	if (task_cpu(p) != new_cpu) {
		if (p->sched_class->migrate_task_rq)
			p->sched_class->migrate_task_rq(p, new_cpu);
		p->se.nr_migrations++;
		perf_sw_event(PERF_COUNT_SW_CPU_MIGRATIONS, 1, NULL, 0);
	}

	__set_task_cpu(p, new_cpu);
}

__set_task_cpu()

// ARM10C 20140913
// idle: &init_task, cpu: 0
// ARM10C 20161015
// p: kmem_cache#15-oX (struct task_struct), this_cpu: 0
static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu)
{
	// p: &init_task, cpu: 0
	set_task_rq(p, cpu);

	// set_task_rq 에서 한일:
	// (&init_task)->se.cfs_rq: [pcp0] &(&runqueues)->cfs
	// (&init_task)->se.parent: NULL
	// (&init_task)->rt.rt_rq: [pcp0] &(&runqueues)->rt
	// (&init_task)->rt.parent: NULL

#ifdef CONFIG_SMP // CONFIG_SMP=y
	/*
	 * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be
	 * successfuly executed on another CPU. We must ensure that updates of
	 * per-task data have been completed by this moment.
	 */
	smp_wmb();
	// memory barrier 수행

	// p: &init_task, cpu: 0
	// (&init_task)->stack: &init_thread_info
	// task_thread_info(&init_task)->cpu: ((struct thread_info *)(&init_task)->stack)->cpu
	task_thread_info(p)->cpu = cpu;
	// task_thread_info(&init_task)->cpu: ((struct thread_info *)(&init_task)->stack)->cpu: 0

	// p->wake_cpu: (&init_task)->wake_cpu, cpu: 0
	p->wake_cpu = cpu;
	// p->wake_cpu: (&init_task)->wake_cpu: 0
#endif
}

sched_fork()

// ARM10C 20161008
// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
void sched_fork(unsigned long clone_flags, struct task_struct *p)
{
	unsigned long flags;

	// get_cpu(): 0
	int cpu = get_cpu();
	// cpu: 0

	// clone_flags: 0x00800B00, p: kmem_cache#15-oX (struct task_struct)
	__sched_fork(clone_flags, p);

	// __sched_fork에서 한일:
	// (&kmem_cache#15-oX (struct task_struct))->on_rq: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.on_rq: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.exec_start: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.sum_exec_runtime: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.prev_sum_exec_runtime: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.nr_migrations: 0
	// (&kmem_cache#15-oX (struct task_struct))->se.vruntime: 0
	// &(&kmem_cache#15-oX (struct task_struct))->se.group_node의 리스트 초기화
	// &(&kmem_cache#15-oX (struct task_struct))->rt.run_list의 리스트 초기화

	/*
	 * We mark the process as running here. This guarantees that
	 * nobody will actually run it, and a signal or other external
	 * event cannot wake it up and insert it on the runqueue either.
	 */

	// p->state: (kmem_cache#15-oX (struct task_struct))->state, TASK_RUNNING: 0
	p->state = TASK_RUNNING;
	// p->state: (kmem_cache#15-oX (struct task_struct))->state: 0

	/*
	 * Make sure we do not leak PI boosting priority to the child.
	 */
	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio,
	// current: &init_task, current->normal_prio: (&init_task)->normal_prio: 120
	p->prio = current->normal_prio;
	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio: 120

	/*
	 * Revert to default priority/policy on fork if requested.
	 */
	// p->>sched_reset_on_fork: (kmem_cache#15-oX (struct task_struct))->sched_reset_on_fork: 0
	if (unlikely(p->sched_reset_on_fork)) {
		if (task_has_rt_policy(p)) {
			p->policy = SCHED_NORMAL;
			p->static_prio = NICE_TO_PRIO(0);
			p->rt_priority = 0;
		} else if (PRIO_TO_NICE(p->static_prio) < 0)
			p->static_prio = NICE_TO_PRIO(0);

		p->prio = p->normal_prio = __normal_prio(p);
		set_load_weight(p);

		/*
		 * We don't need the reset flag anymore after the fork. It has
		 * fulfilled its duty:
		 */
		p->sched_reset_on_fork = 0;
	}

	// p->prio: (kmem_cache#15-oX (struct task_struct))->prio: 120, rt_prio(120): 0
	if (!rt_prio(p->prio))
		// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class
		p->sched_class = &fair_sched_class;
		// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class: &fair_sched_class

// 2016/10/15 종료

	// p->sched_class: (kmem_cache#15-oX (struct task_struct))->sched_class: &fair_sched_class,
	// p->sched_class->task_fork: (&fair_sched_class)->task_fork: task_fork_fair
	if (p->sched_class->task_fork)
		// p->sched_class->task_fork: (&fair_sched_class)->task_fork: task_fork_fair,
		// p: kmem_cache#15-oX (struct task_struct),
		// task_fork_fair(kmem_cache#15-oX (struct task_struct))
		p->sched_class->task_fork(p);

		// task_fork_fair 에서 한일:

	/*
	 * The child is not yet in the pid-hash so no cgroup attach races,
	 * and the cgroup is pinned to this child due to cgroup_fork()
	 * is ran before sched_fork().
	 *
	 * Silence PROVE_RCU.
	 */
	raw_spin_lock_irqsave(&p->pi_lock, flags);
	set_task_cpu(p, cpu);
	raw_spin_unlock_irqrestore(&p->pi_lock, flags);

#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
	if (likely(sched_info_on()))
		memset(&p->sched_info, 0, sizeof(p->sched_info));
#endif
#if defined(CONFIG_SMP)
	p->on_cpu = 0;
#endif
	init_task_preempt_count(p);
#ifdef CONFIG_SMP
	plist_node_init(&p->pushable_tasks, MAX_PRIO);
#endif

	put_cpu();
}

log

  • 1st log
bcc0aa2..af56134  master     -> origin/master
Updating bcc0aa2..af56134
Fast-forward
arch/arm/include/asm/atomic.h           |   4 +
arch/arm/include/asm/thread_info.h      |   1 +
fs/file.c                               | 135 +++++++++++++++++++++++++++
include/asm-generic/bitops/non-atomic.h |   2 +
include/asm-generic/bitsperlong.h       |   1 +
include/asm-generic/current.h           |   1 +
include/asm-generic/preempt.h           |  13 +++
include/linux/audit.h                   |   4 +-
include/linux/compiler-gcc.h            |   1 +
include/linux/fdtable.h                 |   8 ++
include/linux/fs.h                      |   1 +
include/linux/gfp.h                     |   1 +
include/linux/list.h                    |   4 +
include/linux/lockdep.h                 |   2 +
include/linux/perf_event.h              |   2 +
include/linux/plist.h                   |  16 ++++
include/linux/preempt.h                 |   4 +
include/linux/preempt_mask.h            |  15 +++
include/linux/rcupdate.h                |  29 +++++-
include/linux/sched.h                   |  17 +++-
include/linux/sched/rt.h                |   1 +
include/linux/sem.h                     |   2 +
include/linux/smp.h                     |   1 +
include/linux/spinlock.h                |   8 ++
include/linux/thread_info.h             |   3 +
include/trace/events/sched.h            |   2 +
include/uapi/asm-generic/errno-base.h   |   1 +
include/uapi/linux/sched.h              |   4 +
ipc/sem.c                               |   7 ++
kernel/fork.c                           | 159 +++++++++++++++++++++++++++++++-
kernel/locking/lockdep.c                |   2 +
kernel/rcu/update.c                     |   2 +-
kernel/sched/core.c                     |  79 ++++++++++++++--
kernel/sched/fair.c                     |   2 +-
kernel/sched/sched.h                    |   2 +
mm/slub.c                               |   2 +
36 files changed, 524 insertions(+), 14 deletions(-)