tty: Fix ldisc leak in failed tty_init_dev()

release_tty() leaks the ldisc instance when called directly (rather
than when releasing the file descriptor from tty_release()).

Since tty_ldisc_release() clears tty->ldisc, releasing the ldisc
instance at tty teardown if tty->ldisc is non-null is not in danger
of double-releasing the ldisc.

Remove deinitialize_tty_struct() now that free_tty_struct() always
performs the tty_ldisc_deinit().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

3 files changed, 8 insertions, 22 deletions

diff --git a/drivers/tty/pty.c b/drivers/tty/pty.c
index b3110040164a..8cbe802bff1d 100644
--- a/drivers/tty/pty.c
+++ b/drivers/tty/pty.c
@@ -408,7 +408,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
                    the easy way .. */
                 retval = tty_init_termios(tty);
                 if (retval)
-                        goto err_deinit_tty;
+                        goto err_free_tty;
 
                 retval = tty_init_termios(o_tty);
                 if (retval)
@@ -447,8 +447,7 @@ static int pty_common_install(struct tty_driver *driver, struct tty_struct *tty,
 err_free_termios:
         if (legacy)
                 tty_free_termios(tty);
-err_deinit_tty:
-        deinitialize_tty_struct(o_tty);
+err_free_tty:
         free_tty_struct(o_tty);
 err_put_module:
         module_put(driver->other->owner);
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 5cec01c75691..c9f2365167df 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -172,6 +172,7 @@ void free_tty_struct(struct tty_struct *tty)
 {
         if (!tty)
                 return;
+        tty_ldisc_deinit(tty);
         put_device(tty->dev);
         kfree(tty->write_buf);
         tty->magic = 0xDEADDEAD;
@@ -1529,7 +1530,7 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
         tty_lock(tty);
         retval = tty_driver_install_tty(driver, tty);
         if (retval < 0)
-                goto err_deinit_tty;
+                goto err_free_tty;
 
         if (!tty->port)
                 tty->port = driver->ports[idx];
@@ -1551,9 +1552,8 @@ struct tty_struct *tty_init_dev(struct tty_driver *driver, int idx)
         /* Return the tty locked so that it cannot vanish under the caller */
         return tty;
 
-err_deinit_tty:
+err_free_tty:
         tty_unlock(tty);
-        deinitialize_tty_struct(tty);
         free_tty_struct(tty);
 err_module_put:
         module_put(driver->owner);
@@ -3163,20 +3163,6 @@ struct tty_struct *alloc_tty_struct(struct tty_driver *driver, int idx)
 }
 
 /**
- *      deinitialize_tty_struct
- *      @tty: tty to deinitialize
- *
- *      This subroutine deinitializes a tty structure that has been newly
- *      allocated but tty_release cannot be called on that yet.
- *
- *      Locking: none - tty in question must not be exposed at this point
- */
-void deinitialize_tty_struct(struct tty_struct *tty)
-{
-        tty_ldisc_deinit(tty);
-}
-
-/**
  *      tty_put_char    -       write one character to a tty
  *      @tty: tty
  *      @ch: character
diff --git a/drivers/tty/tty_ldisc.c b/drivers/tty/tty_ldisc.c
index a054d03c22e7..49f0cea1e538 100644
--- a/drivers/tty/tty_ldisc.c
+++ b/drivers/tty/tty_ldisc.c
@@ -797,7 +797,7 @@ void tty_ldisc_init(struct tty_struct *tty)
 }
 
 /**
- *      tty_ldisc_init          -       ldisc cleanup for new tty
+ *      tty_ldisc_deinit        -       ldisc cleanup for new tty
  *      @tty: tty that was allocated recently
  *
  *      The tty structure must not becompletely set up (tty_ldisc_setup) when
@@ -805,7 +805,8 @@ void tty_ldisc_init(struct tty_struct *tty)
  */
 void tty_ldisc_deinit(struct tty_struct *tty)
 {
-        tty_ldisc_put(tty->ldisc);
+        if (tty->ldisc)
+                tty_ldisc_put(tty->ldisc);
         tty->ldisc = NULL;
 }