Merge tag 'kvm-arm-for-4.3-rc2-2' of git://git.kernel.org/pub/scm/linux/kernel/git...

[firefly-linux-kernel-4.4.55.git] / drivers / tty / n_tty.c

diff --git a/drivers/tty/n_tty.c b/drivers/tty/n_tty.c
index ee8bfacf20716481a23a60325b5c99ba9da35508..20932cc9c8f71681038bf5e505fec87d9c402280 100644 (file)
--- a/drivers/tty/n_tty.c
+++ b/drivers/tty/n_tty.c
@@ -2147,6 +2147,8 @@ extern ssize_t redirected_tty_write(struct file *, const char __user *,
 
 static int job_control(struct tty_struct *tty, struct file *file)
 {
+       struct pid *pgrp;
+
        /* Job control check -- must be done at start and after
           every sleep (POSIX.1 7.1.1.4). */
        /* NOTE: not yet done after every sleep pending a thorough
@@ -2156,18 +2158,25 @@ static int job_control(struct tty_struct *tty, struct file *file)
            current->signal->tty != tty)
                return 0;
 
+       rcu_read_lock();
+       pgrp = task_pgrp(current);
+
        spin_lock_irq(&tty->ctrl_lock);
        if (!tty->pgrp)
                printk(KERN_ERR "n_tty_read: no tty->pgrp!\n");
-       else if (task_pgrp(current) != tty->pgrp) {
+       else if (pgrp != tty->pgrp) {
                spin_unlock_irq(&tty->ctrl_lock);
-               if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned())
+               if (is_ignored(SIGTTIN) || is_current_pgrp_orphaned()) {
+                       rcu_read_unlock();
                        return -EIO;
-               kill_pgrp(task_pgrp(current), SIGTTIN, 1);
+               }
+               kill_pgrp(pgrp, SIGTTIN, 1);
+               rcu_read_unlock();
                set_thread_flag(TIF_SIGPENDING);
                return -ERESTARTSYS;
        }
        spin_unlock_irq(&tty->ctrl_lock);
+       rcu_read_unlock();
        return 0;
 }