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>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/drivers/tty/n_gsm.c b/drivers/tty/n_gsm.c
index d603ca32e19ac770d6f1273756f4e913f7938754..d1902696e27256c304fa7439fdf0279416d0b941 100644 (file)
--- a/drivers/tty/n_gsm.c
+++ b/drivers/tty/n_gsm.c
@@ -868,7 +868,7 @@ 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;
@@ -892,8 +892,11 @@ 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) */