printk/panic: prevent spin waiting in printk()

hulk inclusion
category: bugfix
bugzilla: 41832, https://gitee.com/openeuler/kernel/issues/I4JKT1
CVE: NA

-----------------------------------------------

When one cpu panic, the panic cpu send NMI to other cpus, if one of
the non-panic cpus is in printk() and get stopped before release
console_waiter, the panic cpu may spin waiting.

Here just release console_waiter directly after all non-panic cpus
get stopped.
Signed-off-by: NChen Zhou <chenzhou10@huawei.com>
Reviewed-by: NJian Cheng <cj.chengjian@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NChen Zhou <chenzhou10@huawei.com>
Signed-off-by: NCheng Jian <cj.chengjian@huawei.com>
Reviewed-by: NXie XiuQi <xiexiuqi@huawei.com>
Signed-off-by: NZheng Zengkai <zhengzengkai@huawei.com>

kernel/printk/printk.c

@@ -1751,9 +1751,10 @@ void zap_locks(void)
 
 	if (raw_spin_is_locked(&console_owner_lock)) {
 		raw_spin_lock_init(&console_owner_lock);
-		console_owner = NULL;
-		console_waiter = false;
 	}
+
+	console_owner = NULL;
+	console_waiter = false;
 }
 
 /**