n_gsm: memory leak in uplink error path

commit 88ed2a60610974443335c924d7cb8e5dcf9dbdc1 upstream.

Uplink (TX) network data will go through gsm_dlci_data_output_framed
there is a bug where if memory allocation fails, the skb which
has already been pulled off the list will be lost.

In addition TX skbs were being processed in LIFO order

Fixed the memory leak, and changed to FIFO order processing

Signed-off-by: Russ Gorby <russ.gorby@intel.com>
Tested-by: Kappel, LaurentX <laurentx.kappel@intel.com>
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index b770136d54995d21566693d18d5a5b0df75a6d97..fee6bedee8a24a00368c8be64331e045dab9c97b 100644 (file)
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -842,7 +842,7 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 
        /* dlci->skb is locked by tx_lock */
        if (dlci->skb == NULL) {
-               dlci->skb = skb_dequeue(&dlci->skb_list);
+               dlci->skb = skb_dequeue_tail(&dlci->skb_list);
                if (dlci->skb == NULL)
                        return 0;
                first = 1;
@@ -866,8 +866,11 @@ static int gsm_dlci_data_output_framed(struct gsm_mux *gsm,
 
        /* FIXME: need a timer or something to kick this so it can't
           get stuck with no work outstanding and no buffer free */
-       if (msg == NULL)
+       if (msg == NULL) {
+               skb_queue_tail(&dlci->skb_list, dlci->skb);
+               dlci->skb = NULL;
                return -ENOMEM;
+       }
        dp = msg->data;
 
        if (dlci->adaption == 4) { /* Interruptible framed (Packetised Data) */