tty: Fix unbalanced BKL handling in error path

Arnd noted:

After the "retry_open:" label, we first get the tty_mutex
and then the BKL. However a the end of tty_open, we jump
back to retry_open with the BKL still held. If we run into
this case, the tty_open function will be left with the BKL
still held.

Signed-off-by: Alan Cox <alan@linux.intel.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/char/tty_io.c b/drivers/char/tty_io.c
index 6da962c..d71f0fc 100644 (file)
--- a/drivers/char/tty_io.c
+++ b/drivers/char/tty_io.c
@@ -1875,6 +1875,7 @@ got_driver:
                 */
                if (filp->f_op == &hung_up_tty_fops)
                        filp->f_op = &tty_fops;
+               unlock_kernel();
                goto retry_open;
        }
        unlock_kernel();