dump: Add comments on task seizing and stopping

Signed-off-by: Cyrill Gorcunov <gorcunov@gmail.com>

cr-dump.c

@@ -1070,6 +1070,12 @@ int cr_dump_tasks(pid_t pid, struct cr_options *opts)
 	if (collect_pstree(pid))
 		goto err;
 
+	/*
+	 * Since ptrace-seize doesn't work on frozen tasks
+	 * we stick with explicit tasks stopping via stop
+	 * signal, but in future it's aimed to switch to
+	 * kernel freezer.
+	 */
 	list_for_each_entry(item, &pstree_list, list) {
 		stop_task(item->pid);
 		if (opts->leader_only)

util.c

@@ -192,6 +192,13 @@ int unseize_task(pid_t pid)
 	return ptrace(PTRACE_DETACH, pid, NULL, NULL);
 }
 
+/*
+ * This routine seizes task putting it into a special
+ * state where we can manipulate the task via ptrace
+ * inteface, and finally we can detach ptrace out of
+ * of it so the task would not know if it was saddled
+ * up with someone else.
+ */
 int seize_task(pid_t pid)
 {
 	siginfo_t si;