[RFC v12][PATCH 13/14] Checkpoint multiple processes

[Nathan Lynch]

> +/* count number of tasks in tree (and optionally fill pid's in array) */
> +static int cr_tree_count_tasks(struct cr_ctx *ctx)
> +{
> +	struct task_struct *root = ctx->root_task;
> +	struct task_struct *task = root;
> +	struct task_struct *parent = NULL;
> +	struct task_struct **tasks_arr = ctx->tasks_arr;
> +	int tasks_nr = ctx->tasks_nr;
> +	int nr = 0;
> +
> +	read_lock(&tasklist_lock);
> +
> +	/* count tasks via DFS scan of the tree */
> +	while (1) {
> +		if (tasks_arr) {
> +			/* unlikely, but ... */
> +			if (nr == tasks_nr)
> +				return -EBUSY;	/* cleanup in cr_ctx_free() */

Returns without unlocking tasklist_lock?