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authorJohan Hovold <johan@kernel.org>2017-11-03 17:30:55 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2017-11-28 18:00:50 +0300
commit8bcd4e6a8decac251d55c4377e2e67f052777ce0 (patch)
treee9ecd5cb20a5a37a2f255d8d51622be7eec2b5de /drivers/tty
parentfd00cf81a9a84776ba58e56bd042c726dcf75cf3 (diff)
downloadlinux-8bcd4e6a8decac251d55c4377e2e67f052777ce0.tar.xz
serdev: ttyport: fix NULL-deref on hangup
Make sure to use a properly refcounted tty_struct in write_wake up to avoid dereferencing a NULL-pointer when a port is being hung up. Fixes: bed35c6dfa6a ("serdev: add a tty port controller driver") Cc: stable <stable@vger.kernel.org> # 4.11 Signed-off-by: Johan Hovold <johan@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/serdev/serdev-ttyport.c11
1 files changed, 9 insertions, 2 deletions
diff --git a/drivers/tty/serdev/serdev-ttyport.c b/drivers/tty/serdev/serdev-ttyport.c
index 09fbdd52a561..12cb9139073e 100644
--- a/drivers/tty/serdev/serdev-ttyport.c
+++ b/drivers/tty/serdev/serdev-ttyport.c
@@ -49,12 +49,19 @@ static void ttyport_write_wakeup(struct tty_port *port)
{
struct serdev_controller *ctrl = port->client_data;
struct serport *serport = serdev_controller_get_drvdata(ctrl);
+ struct tty_struct *tty;
+
+ tty = tty_port_tty_get(port);
+ if (!tty)
+ return;
- if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &port->tty->flags) &&
+ if (test_and_clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags) &&
test_bit(SERPORT_ACTIVE, &serport->flags))
serdev_controller_write_wakeup(ctrl);
- wake_up_interruptible_poll(&port->tty->write_wait, POLLOUT);
+ wake_up_interruptible_poll(&tty->write_wait, POLLOUT);
+
+ tty_kref_put(tty);
}
static const struct tty_port_client_operations client_ops = {