[PATCH 5.0 095/146] USB: serial: mos7720: fix mos_parport refcount imbalance on error path

From: Greg Kroah-Hartman
Date: Mon Apr 01 2019 - 13:09:03 EST

5.0-stable review patch. If anyone has any objections, please let me know.


From: Lin Yi <teroincn@xxxxxxx>

commit 2908b076f5198d231de62713cb2b633a3a4b95ac upstream.

The write_parport_reg_nonblock() helper takes a reference to the struct
mos_parport, but failed to release it in a couple of error paths after
allocation failures, leading to a memory leak.

Johan said that move the kref_get() and mos_parport assignment to the
end of urbtrack initialisation is a better way, so move it. and
mos_parport do not used until urbtrack initialisation.

Signed-off-by: Lin Yi <teroincn@xxxxxxx>
Fixes: b69578df7e98 ("USB: usbserial: mos7720: add support for parallel port on moschip 7715")
Cc: stable <stable@xxxxxxxxxxxxxxx> # 2.6.35
Signed-off-by: Johan Hovold <johan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

drivers/usb/serial/mos7720.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -366,8 +366,6 @@ static int write_parport_reg_nonblock(st
if (!urbtrack)
return -ENOMEM;

- kref_get(&mos_parport->ref_count);
- urbtrack->mos_parport = mos_parport;
urbtrack->urb = usb_alloc_urb(0, GFP_ATOMIC);
if (!urbtrack->urb) {
@@ -388,6 +386,8 @@ static int write_parport_reg_nonblock(st
usb_sndctrlpipe(usbdev, 0),
(unsigned char *)urbtrack->setup,
NULL, 0, async_complete, urbtrack);
+ kref_get(&mos_parport->ref_count);
+ urbtrack->mos_parport = mos_parport;