tty: USB hangup is racy
The USB layer uses tty_hangup to deal with unplugs of the physical hardware
(analogous to loss of carrier) and then frees the resources. However the
tty_hangup is asynchronous. As the hangup can sleep we can use tty_vhangup
which is the non async version to avoid freeing resources too early.
Signed-off-by: Alan Cox <alan@linux.intel.com>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 99188c9..21dd72a 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1161,10 +1161,7 @@
if (port) {
struct tty_struct *tty = tty_port_tty_get(&port->port);
if (tty) {
- /* The hangup will occur asynchronously but
- the object refcounts will sort out all the
- cleanup */
- tty_hangup(tty);
+ tty_vhangup(tty);
tty_kref_put(tty);
}
kill_traffic(port);