USB: cdc-acm: fix potential urb leak and PM imbalance in write

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>

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 61738d9..cd70647 100644 (file)
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -666,7 +666,13 @@ static int acm_tty_write(struct tty_struct *tty,
        memcpy(wb->buf, buf, count);
        wb->len = count;
 
-       usb_autopm_get_interface_async(acm->control);
+       stat = usb_autopm_get_interface_async(acm->control);
+       if (stat) {
+               wb->use = 0;
+               spin_unlock_irqrestore(&acm->write_lock, flags);
+               return stat;
+       }
+
        if (acm->susp_count) {
                usb_anchor_urb(wb->urb, &acm->delayed);
                spin_unlock_irqrestore(&acm->write_lock, flags);