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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>
This commit is contained in:
Bjørn Mork 2013-01-28 23:51:28 +00:00 committed by David S. Miller
parent 6cdd20c380
commit 70c37bf97f
2 changed files with 27 additions and 0 deletions
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25
drivers/net/usb/usbnet.c
View File

@ -380,6 +380,12 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
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 @@ block:
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 @@ int usbnet_open (struct net_device *net)
(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 @@ static void usbnet_bh (unsigned long param)
}
}
/* 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) {

2
include/linux/usb/usbnet.h
View File

@ -33,6 +33,7 @@ struct usbnet {
wait_queue_head_t *wait;
struct mutex phy_mutex;
unsigned char suspend_count;
unsigned char pkt_cnt, pkt_err;
/* i/o info: pipes etc */
unsigned in, out;
@ -70,6 +71,7 @@ struct usbnet {
# define EVENT_DEV_OPEN 7
# define EVENT_DEVICE_REPORT_IDLE 8
# define EVENT_NO_RUNTIME_PM 9
# define EVENT_RX_KILL 10
};
static inline struct usb_driver *driver_of(struct usb_interface *intf)