[PATCH 3.2 038/125] USB: cdc-acm: fix potential urb leak and PM imbalance in write

Ben Hutchings
2014-07-08T19:19:18Z

From: Johan Hovold <jhovold@gmail.com>

commit 183a45087d126d126e8dd1d9b2602fc129dff9ad upstream.

Make sure to check return value of autopm get in write() in order to
avoid urb leak and PM counter imbalance on errors.

Fixes: 11ea859d64b6 ("USB: additional power savings for cdc-acm devices
that support remote wakeup")

Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2:
- Adjust context
- Error/status variable is called rc, not stat]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/usb/class/cdc-acm.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -191,7 +191,13 @@ static int acm_write_start(struct acm *a

dev_vdbg(&acm->data->dev, "%s - susp_count %d\n", __func__,
acm->susp_count);
- usb_autopm_get_interface_async(acm->control);
+ rc = usb_autopm_get_interface_async(acm->control);
+ if (rc) {
+ wb->use = 0;
+ spin_unlock_irqrestore(&acm->write_lock, flags);
+ return rc;
+ }
+
if (acm->susp_count) {
usb_anchor_urb(wb->urb, &acm->delayed);
spin_unlock_irqrestore(&acm->write_lock, flags);