Pull percpu-dtc into release branch

[linux-drm-fsl-dcu.git] / drivers / char / tty_io.c

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index f24c26d2dba116fbbd833eb29a5acf07facddc42..7a32df59490750775b6df3b718e0b33be2ee8514 100644 (file)
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1376,6 +1376,8 @@ static void do_tty_hangup(struct work_struct *work)
        read_unlock(&tasklist_lock);
 
        tty->flags = 0;
+       put_pid(tty->session);
+       put_pid(tty->pgrp);
        tty->session = NULL;
        tty->pgrp = NULL;
        tty->ctrl_status = 0;
@@ -1901,6 +1903,20 @@ static int init_dev(struct tty_driver *driver, int idx,
        /* check whether we're reopening an existing tty */
        if (driver->flags & TTY_DRIVER_DEVPTS_MEM) {
                tty = devpts_get_tty(idx);
+               /*
+                * If we don't have a tty here on a slave open, it's because
+                * the master already started the close process and there's
+                * no relation between devpts file and tty anymore.
+                */
+               if (!tty && driver->subtype == PTY_TYPE_SLAVE) {
+                       retval = -EIO;
+                       goto end_init;
+               }
+               /*
+                * It's safe from now on because init_dev() is called with
+                * tty_mutex held and release_dev() won't change tty->count
+                * or tty->flags without having to grab tty_mutex
+                */
                if (tty && driver->subtype == PTY_TYPE_MASTER)
                        tty = tty->link;
        } else {
@@ -3827,6 +3843,9 @@ static struct pid *__proc_set_tty(struct task_struct *tsk, struct tty_struct *tt
 {
        struct pid *old_pgrp;
        if (tty) {
+               /* We should not have a session or pgrp to here but.... */
+               put_pid(tty->session);
+               put_pid(tty->pgrp);
                tty->session = get_pid(task_session(tsk));
                tty->pgrp = get_pid(task_pgrp(tsk));
        }