On Tue, 12 Nov 2019 11:17:47 +0900
Sergey Senozhatsky [off-list ref] wrote:

void show_stack(struct task_struct *task, unsigned long *sp, int log_level)
{
	printk_emergency_enter(log_level);
	__show_stack(task, sp);
	printk_emergency_exit();
}
// - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - //

show_stack() never schedules, disabling preemption around it should
not change anything. Should it be interrupted, we will handle it via
preempt count.

Please no! The whole point of the printk rewrite was to allow for
printk to be preemptible and used in more contexts. The show_stack() can
be all over the place and is not a fast function. Let's not disable
preemption for it.

-- Steve