net: usbnet: prevent buggy devices from killing us
A device sending 0 length frames as fast as it can has been
observed killing the host system due to the resulting memory
pressure.
Temporarily disable RX skb allocation and URB submission when
the current error ratio is high, preventing us from trying to
allocate an infinite number of skbs. Reenable as soon as we
are finished processing the done queue, allowing the device
to continue working after short error bursts.
Signed-off-by: Bjørn Mork <bjorn@mork.no>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index f34b2eb..9778377 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -380,6 +380,12 @@
unsigned long lockflags;
size_t size = dev->rx_urb_size;
+ /* prevent rx skb allocation when error ratio is high */
+ if (test_bit(EVENT_RX_KILL, &dev->flags)) {
+ usb_free_urb(urb);
+ return -ENOLINK;
+ }
+
skb = __netdev_alloc_skb_ip_align(dev->net, size, flags);
if (!skb) {
netif_dbg(dev, rx_err, dev->net, "no rx skb\n");
@@ -539,6 +545,17 @@
break;
}
+ /* stop rx if packet error rate is high */
+ if (++dev->pkt_cnt > 30) {
+ dev->pkt_cnt = 0;
+ dev->pkt_err = 0;
+ } else {
+ if (state == rx_cleanup)
+ dev->pkt_err++;
+ if (dev->pkt_err > 20)
+ set_bit(EVENT_RX_KILL, &dev->flags);
+ }
+
state = defer_bh(dev, skb, &dev->rxq, state);
if (urb) {
@@ -791,6 +808,11 @@
(dev->driver_info->flags & FLAG_FRAMING_AX) ? "ASIX" :
"simple");
+ /* reset rx error state */
+ dev->pkt_cnt = 0;
+ dev->pkt_err = 0;
+ clear_bit(EVENT_RX_KILL, &dev->flags);
+
// delay posting reads until we're fully open
tasklet_schedule (&dev->bh);
if (info->manage_power) {
@@ -1254,6 +1276,9 @@
}
}
+ /* restart RX again after disabling due to high error rate */
+ clear_bit(EVENT_RX_KILL, &dev->flags);
+
// waiting for all pending urbs to complete?
if (dev->wait) {
if ((dev->txq.qlen + dev->rxq.qlen + dev->done.qlen) == 0) {