--- zzzz-none-000/linux-3.10.107/arch/um/drivers/mconsole_kern.c	2017-06-27 09:49:32.000000000 +0000
+++ scorpion-7490-727/linux-3.10.107/arch/um/drivers/mconsole_kern.c	2021-02-04 17:41:59.000000000 +0000
@@ -133,7 +133,7 @@
 	ptr += strlen("proc");
 	ptr = skip_spaces(ptr);
 
-	file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY);
+	file = file_open_root(mnt->mnt_root, mnt, ptr, O_RDONLY, 0);
 	if (IS_ERR(file)) {
 		mconsole_reply(req, "Failed to open file", 1, 0);
 		printk(KERN_ERR "open /proc/%s: %ld\n", ptr, PTR_ERR(file));
@@ -645,11 +645,9 @@
 
 static void stack_proc(void *arg)
 {
-	struct task_struct *from = current, *to = arg;
+	struct task_struct *task = arg;
 
-	to->thread.saved_task = from;
-	rcu_user_hooks_switch(from, to);
-	switch_to(from, to, from);
+	show_stack(task, NULL);
 }
 
 /*