USB: serial: mos7720: fix mos_parport refcount imbalance on error path

WannaTen · jhovold · commit 2908b076f519 · 2019-03-20T13:58:42.000+01:00
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@163.com> Fixes: b69578d ("USB: usbserial: mos7720: add support for parallel port on moschip 7715") Cc: stable <stable@vger.kernel.org> # 2.6.35 Signed-off-by: Johan Hovold <johan@kernel.org>
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
@@ -366,8 +366,6 @@ static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
 	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) {
 		kfree(urbtrack);
@@ -388,6 +386,8 @@ static int write_parport_reg_nonblock(struct mos7715_parport *mos_parport,
 			     usb_sndctrlpipe(usbdev, 0),
 			     (unsigned char *)urbtrack->setup,
 			     NULL, 0, async_complete, urbtrack);
+	kref_get(&mos_parport->ref_count);
+	urbtrack->mos_parport = mos_parport;
 	kref_init(&urbtrack->ref_count);
 	INIT_LIST_HEAD(&urbtrack->urblist_entry);
 
