copy_process

Linux 6.18.37 LTS: kernel/fork.c
Linux 6.18.37 LTS: kernel/sched/core.c
Linux 6.18.37 LTS: kernel/cred.c

	lockdep_init_task(&init_task);
	uprobes_init();
}

int __weak arch_dup_task_struct(struct task_struct *dst,
					       struct task_struct *src)
{
	*dst = *src;
	return 0;
}

void set_task_stack_end_magic(struct task_struct *tsk)
{
	unsigned long *stackend;

	stackend = end_of_stack(tsk);
	*stackend = STACK_END_MAGIC;	/* for overflow detection */
}

static struct task_struct *dup_task_struct(struct task_struct *orig, int node)
{
	struct task_struct *tsk;
	int err;

	if (node == NUMA_NO_NODE)
		node = tsk_fork_get_node(orig);
	tsk = alloc_task_struct_node(node);
	if (!tsk)
		return NULL;

	err = arch_dup_task_struct(tsk, orig);
	if (err)
		goto free_tsk;

	err = alloc_thread_stack_node(tsk, node);
	if (err)
		goto free_tsk;

#ifdef CONFIG_THREAD_INFO_IN_TASK

/*
 * This is like kernel_clone(), but shaved down and tailored to just
 * creating io_uring workers. It returns a created task, or an error pointer.
 * The returned task is inactive, and the caller must fire it up through
 * wake_up_new_task(p). All signals are blocked in the created task.
 */
struct task_struct *create_io_thread(int (*fn)(void *), void *arg, int node)
{
	unsigned long flags = CLONE_FS|CLONE_FILES|CLONE_SIGHAND|CLONE_THREAD|
				CLONE_IO;
	struct kernel_clone_args args = {
		.flags		= ((lower_32_bits(flags) | CLONE_VM |
				    CLONE_UNTRACED) & ~CSIGNAL),
		.exit_signal	= (lower_32_bits(flags) & CSIGNAL),
		.fn		= fn,
		.fn_arg		= arg,
		.io_thread	= 1,
		.user_worker	= 1,
	};

	return copy_process(NULL, 0, node, &args);
}

/*
 *  Ok, this is the main fork-routine.
 *
 * It copies the process, and if successful kick-starts
 * it and waits for it to finish using the VM if required.
 *
 * args->exit_signal is expected to be checked for sanity by the caller.
 */
pid_t kernel_clone(struct kernel_clone_args *args)
{
	u64 clone_flags = args->flags;
	struct completion vfork;
	struct pid *pid;
	struct task_struct *p;
	int trace = 0;
	pid_t nr;