printk: wake up all waiters

There can be multiple tasks waiting for new records. They should
all be woken. Use wake_up_interruptible_all() instead of
wake_up_interruptible().

Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20220421212250.565456-5-john.ogness@linutronix.de

kernel/printk/printk.c

@@ -3326,7 +3326,7 @@ static void wake_up_klogd_work_func(struct irq_work *irq_work)
 	}
 
 	if (pending & PRINTK_PENDING_WAKEUP)
-		wake_up_interruptible(&log_wait);
+		wake_up_interruptible_all(&log_wait);
 }
 
 static DEFINE_PER_CPU(struct irq_work, wake_up_klogd_work) =