Merge "tty: Fix ->session locking" (c5bfb24d) · Commits · e / devices / android_kernel_oneplus_sm7250

drivers/tty/tty_io.c

+6 −1

Original line number	Diff line number	Diff line
		@@ -2751,10 +2751,14 @@ void __do_SAK(struct tty_struct *tty)
		struct task_struct g, p;
		struct pid *session;
		int i;
		unsigned long flags;

		if (!tty)
		return;
		session = tty->session;

		spin_lock_irqsave(&tty->ctrl_lock, flags);
		session = get_pid(tty->session);
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);

		tty_ldisc_flush(tty);

		@@ -2786,6 +2790,7 @@ void __do_SAK(struct tty_struct *tty)
		task_unlock(p);
		} while_each_thread(g, p);
		read_unlock(&tasklist_lock);
		put_pid(session);
		#endif
		}

drivers/tty/tty_jobctrl.c

+31 −13

Original line number	Diff line number	Diff line
		@@ -103,8 +103,8 @@ static void __proc_set_tty(struct tty_struct *tty)
		put_pid(tty->session);
		put_pid(tty->pgrp);
		tty->pgrp = get_pid(task_pgrp(current));
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
		tty->session = get_pid(task_session(current));
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
		if (current->signal->tty) {
		tty_debug(tty, "current tty %s not NULL!!\n",
		current->signal->tty->name);
		@@ -293,20 +293,23 @@ void disassociate_ctty(int on_exit)
		spin_lock_irq(&current->sighand->siglock);
		put_pid(current->signal->tty_old_pgrp);
		current->signal->tty_old_pgrp = NULL;

		tty = tty_kref_get(current->signal->tty);
		spin_unlock_irq(&current->sighand->siglock);

		if (tty) {
		unsigned long flags;

		tty_lock(tty);
		spin_lock_irqsave(&tty->ctrl_lock, flags);
		put_pid(tty->session);
		put_pid(tty->pgrp);
		tty->session = NULL;
		tty->pgrp = NULL;
		spin_unlock_irqrestore(&tty->ctrl_lock, flags);
		tty_unlock(tty);
		tty_kref_put(tty);
		}

		spin_unlock_irq(&current->sighand->siglock);
		/* Now clear signal->tty under the lock */
		read_lock(&tasklist_lock);
		session_clear_tty(task_session(current));
		@@ -477,14 +480,19 @@ static int tiocspgrp(struct tty_struct tty, struct tty_struct real_tty, pid_t
		return -ENOTTY;
		if (retval)
		return retval;
		if (!current->signal->tty \|\|
		(current->signal->tty != real_tty) \|\|
		(real_tty->session != task_session(current)))
		return -ENOTTY;

		if (get_user(pgrp_nr, p))
		return -EFAULT;
		if (pgrp_nr < 0)
		return -EINVAL;

		spin_lock_irq(&real_tty->ctrl_lock);
		if (!current->signal->tty \|\|
		(current->signal->tty != real_tty) \|\|
		(real_tty->session != task_session(current))) {
		retval = -ENOTTY;
		goto out_unlock_ctrl;
		}
		rcu_read_lock();
		pgrp = find_vpid(pgrp_nr);
		retval = -ESRCH;
		@@ -494,12 +502,12 @@ static int tiocspgrp(struct tty_struct tty, struct tty_struct real_tty, pid_t
		if (session_of_pgrp(pgrp) != task_session(current))
		goto out_unlock;
		retval = 0;
		spin_lock_irq(&real_tty->ctrl_lock);
		put_pid(real_tty->pgrp);
		real_tty->pgrp = get_pid(pgrp);
		spin_unlock_irq(&real_tty->ctrl_lock);
		out_unlock:
		rcu_read_unlock();
		out_unlock_ctrl:
		spin_unlock_irq(&real_tty->ctrl_lock);
		return retval;
		}

		@@ -511,20 +519,30 @@ static int tiocspgrp(struct tty_struct tty, struct tty_struct real_tty, pid_t
		*
		* Obtain the session id of the tty. If there is no session
		* return an error.
		*
		* Locking: none. Reference to current->signal->tty is safe.
		*/
		static int tiocgsid(struct tty_struct tty, struct tty_struct real_tty, pid_t __user *p)
		{
		unsigned long flags;
		pid_t sid;

		/*
		* (tty == real_tty) is a cheap way of
		* testing if the tty is NOT a master pty.
		*/
		if (tty == real_tty && current->signal->tty != real_tty)
		return -ENOTTY;

		spin_lock_irqsave(&real_tty->ctrl_lock, flags);
		if (!real_tty->session)
		goto err;
		sid = pid_vnr(real_tty->session);
		spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);

		return put_user(sid, p);

		err:
		spin_unlock_irqrestore(&real_tty->ctrl_lock, flags);
		return -ENOTTY;
		return put_user(pid_vnr(real_tty->session), p);
		}

		/*

include/linux/tty.h

+4 −0

Original line number	Diff line number	Diff line
		@@ -306,6 +306,10 @@ struct tty_struct {
		struct termiox termiox; / May be NULL for unsupported */
		char name[64];
		struct pid pgrp; / Protected by ctrl lock */
		/*
		* Writes protected by both ctrl lock and legacy mutex, readers must use
		* at least one of them.
		*/
		struct pid *session;
		unsigned long flags;
		int count;