ALPHA: srmcons, fix racy singleton structure (ee024d49) · Commits · 戴 / test

arch/alpha/kernel/srmcons.c

+5 −35

Original line number	Diff line number	Diff line
		@@ -33,7 +33,7 @@ struct srmcons_private {
		struct tty_struct *tty;
		struct timer_list timer;
		spinlock_t lock;
		};
		} srmcons_singleton;

		typedef union _srmcons_result {
		struct {
		@@ -153,44 +153,11 @@ srmcons_chars_in_buffer(struct tty_struct *tty)
		return 0;
		}

		static int
		srmcons_get_private_struct(struct srmcons_private **ps)
		{
		static struct srmcons_private *srmconsp = NULL;
		static DEFINE_SPINLOCK(srmconsp_lock);
		unsigned long flags;
		int retval = 0;

		if (srmconsp == NULL) {
		srmconsp = kmalloc(sizeof(*srmconsp), GFP_KERNEL);
		spin_lock_irqsave(&srmconsp_lock, flags);

		if (srmconsp == NULL)
		retval = -ENOMEM;
		else {
		srmconsp->tty = NULL;
		spin_lock_init(&srmconsp->lock);
		setup_timer(&srmconsp->timer, srmcons_receive_chars,
		(unsigned long)srmconsp);
		}

		spin_unlock_irqrestore(&srmconsp_lock, flags);
		}

		*ps = srmconsp;
		return retval;
		}

		static int
		srmcons_open(struct tty_struct tty, struct file filp)
		{
		struct srmcons_private *srmconsp;
		struct srmcons_private *srmconsp = &srmcons_singleton;
		unsigned long flags;
		int retval;

		retval = srmcons_get_private_struct(&srmconsp);
		if (retval)
		return retval;

		spin_lock_irqsave(&srmconsp->lock, flags);

		@@ -236,6 +203,9 @@ static const struct tty_operations srmcons_ops = {
		static int __init
		srmcons_init(void)
		{
		spin_lock_init(&srmcons_singleton.lock);
		setup_timer(&srmcons_singleton.timer, srmcons_receive_chars,
		(unsigned long)&srmcons_singleton);
		if (srm_is_registered_console) {
		struct tty_driver *driver;
		int err;