console_sem 86 kernel/printk/printk.c static DEFINE_SEMAPHORE(console_sem); console_sem 222 kernel/printk/printk.c down(&console_sem);\ console_sem 237 kernel/printk/printk.c lock_failed = down_trylock(&console_sem); console_sem 254 kernel/printk/printk.c up(&console_sem);