diff options
| author | Johan Hovold <jhovold@gmail.com> | 2013-02-13 17:53:28 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-02-13 18:20:06 +0100 |
| commit | b2ca699076573c94fee9a73cb0d8645383b602a0 (patch) | |
| tree | b9579ce8ed1511a5b3a234b03392b3c095de9231 /drivers/usb/serial/mct_u232.c | |
| parent | USB: option: add Yota / Megafon M100-1 4g modem (diff) | |
| download | linux-b2ca699076573c94fee9a73cb0d8645383b602a0.tar.xz linux-b2ca699076573c94fee9a73cb0d8645383b602a0.zip | |
USB: serial: fix null-pointer dereferences on disconnect
Make sure serial-driver dtr_rts is called with disc_mutex held after
checking the disconnected flag.
Due to a bug in the tty layer, dtr_rts may get called after a device has
been disconnected and the tty-device unregistered. Some drivers have had
individual checks for disconnect to make sure the disconnected interface
was not accessed, but this should really be handled in usb-serial core
(at least until the long-standing tty-bug has been fixed).
Note that the problem has been made more acute with commit 0998d0631001
("device-core: Ensure drvdata = NULL when no driver is bound") as the
port data is now also NULL when dtr_rts is called resulting in further
oopses.
Reported-by: Chris Ruehl <chris.ruehl@gtsys.com.hk>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/serial/mct_u232.c')
| -rw-r--r-- | drivers/usb/serial/mct_u232.c | 22 |
1 files changed, 9 insertions, 13 deletions
diff --git a/drivers/usb/serial/mct_u232.c b/drivers/usb/serial/mct_u232.c index b6911757c855..d9c86516fed4 100644 --- a/drivers/usb/serial/mct_u232.c +++ b/drivers/usb/serial/mct_u232.c @@ -499,19 +499,15 @@ static void mct_u232_dtr_rts(struct usb_serial_port *port, int on) unsigned int control_state; struct mct_u232_private *priv = usb_get_serial_port_data(port); - mutex_lock(&port->serial->disc_mutex); - if (!port->serial->disconnected) { - /* drop DTR and RTS */ - spin_lock_irq(&priv->lock); - if (on) - priv->control_state |= TIOCM_DTR | TIOCM_RTS; - else - priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS); - control_state = priv->control_state; - spin_unlock_irq(&priv->lock); - mct_u232_set_modem_ctrl(port, control_state); - } - mutex_unlock(&port->serial->disc_mutex); + spin_lock_irq(&priv->lock); + if (on) + priv->control_state |= TIOCM_DTR | TIOCM_RTS; + else + priv->control_state &= ~(TIOCM_DTR | TIOCM_RTS); + control_state = priv->control_state; + spin_unlock_irq(&priv->lock); + + mct_u232_set_modem_ctrl(port, control_state); } static void mct_u232_close(struct usb_serial_port *port) |