USB: serial: fix null-pointer dereferences on disconnect
authorJohan Hovold <jhovold@gmail.com>
Wed, 13 Feb 2013 16:53:28 +0000 (17:53 +0100)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 13 Feb 2013 17:20:06 +0000 (09:20 -0800)
commitb2ca699076573c94fee9a73cb0d8645383b602a0
treeb9579ce8ed1511a5b3a234b03392b3c095de9231
parentcd565279e51bedee1b2988e84f9b3bef485adeb6
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>
drivers/usb/serial/ftdi_sio.c
drivers/usb/serial/mct_u232.c
drivers/usb/serial/quatech2.c
drivers/usb/serial/sierra.c
drivers/usb/serial/ssu100.c
drivers/usb/serial/usb-serial.c
drivers/usb/serial/usb_wwan.c