提交 29bd3bc1 编写于 作者: O Olivier Sobrie 提交者: David S. Miller

hso: fix crash when device disappears while serial port is open

When the device disappear, the function hso_disconnect() is called to
perform cleanup. In the cleanup function, hso_free_interface() calls
tty_port_tty_hangup() in view of scheduling a work to hang up the tty if
needed. If the port was not open then hso_serial_ref_free() is called
directly to cleanup everything. Otherwise, hso_serial_ref_free() is called
when the last fd associated to the port is closed.

For each open port, tty_release() will call the close method,
hso_serial_close(), which drops the last kref and call
hso_serial_ref_free() which unregisters, destroys the tty port
and finally frees the structure in which the tty_port structure
is included. Later, in tty_release(), more precisely when release_tty()
is called, the tty_port previously freed is accessed to cancel
the tty buf workqueue and it leads to a crash.

In view of avoiding this crash, we add a cleanup method that is called
at the end of the hangup process and we drop the last kref in this
function when all the ports have been closed, when tty_port is no
more needed and when it is safe to free the structure containing the
tty_port structure.
Signed-off-by: NOlivier Sobrie <olivier@sobrie.be>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
上级 3ac856c1
......@@ -1270,7 +1270,6 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
goto err_out;
D1("Opening %d", serial->minor);
kref_get(&serial->parent->ref);
/* setup */
tty->driver_data = serial;
......@@ -1289,7 +1288,8 @@ static int hso_serial_open(struct tty_struct *tty, struct file *filp)
if (result) {
hso_stop_serial_device(serial->parent);
serial->port.count--;
kref_put(&serial->parent->ref, hso_serial_ref_free);
} else {
kref_get(&serial->parent->ref);
}
} else {
D1("Port was already open");
......@@ -1339,8 +1339,6 @@ static void hso_serial_close(struct tty_struct *tty, struct file *filp)
usb_autopm_put_interface(serial->parent->interface);
mutex_unlock(&serial->parent->mutex);
kref_put(&serial->parent->ref, hso_serial_ref_free);
}
/* close the requested serial port */
......@@ -1391,6 +1389,16 @@ static int hso_serial_write_room(struct tty_struct *tty)
return room;
}
static void hso_serial_cleanup(struct tty_struct *tty)
{
struct hso_serial *serial = tty->driver_data;
if (!serial)
return;
kref_put(&serial->parent->ref, hso_serial_ref_free);
}
/* setup the term */
static void hso_serial_set_termios(struct tty_struct *tty, struct ktermios *old)
{
......@@ -3214,6 +3222,7 @@ static const struct tty_operations hso_serial_ops = {
.close = hso_serial_close,
.write = hso_serial_write,
.write_room = hso_serial_write_room,
.cleanup = hso_serial_cleanup,
.ioctl = hso_serial_ioctl,
.set_termios = hso_serial_set_termios,
.chars_in_buffer = hso_serial_chars_in_buffer,
......
Markdown is supported
0% .
You are about to add 0 people to the discussion. Proceed with caution.
先完成此消息的编辑!
想要评论请 注册