From: "Bjørn Mork" <bjorn@mork•no>
To: Oliver Neukum <oneukum@suse•de>
Cc: linux-usb@vger•kernel.org, netdev@vger•kernel.org
Subject: Re: [RFC] net: usbnet: prevent buggy devices from killing us
Date: Thu, 24 Jan 2013 13:47:40 +0100 [thread overview]
Message-ID: <87y5fig32r.fsf@nemi.mork.no> (raw)
In-Reply-To: <1809412.hrq33TVdWp@linux-5eaq.site> (Oliver Neukum's message of "Thu, 24 Jan 2013 12:31:08 +0100")
Oliver Neukum <oneukum@suse•de> writes:
> On Thursday 24 January 2013 12:22:54 Bjørn Mork wrote:
>
>> Sorry for being daft, but how do I code the "20 among the last 30" part
>> there?
>
> Just by agreeing that you can live with false negatives but not false positives
>
> if (++counter > 30) {
> counter = bogus = 0;
> } else {
> if (is_bogus(packet)
> bogus++;
> if (bogus > counter/2)
> throttle();
> }
So, add two new counters to struct usbnet for this? That seems a little
overkill to me, but I don't see how else to implement anything like that.
It is still not completely clear to me how the throttling/unthrottling
should be done. It tested with static counters (to avoid having to
rebuild everything for this test) and a new EVENT_RX_THROTTLE flag.
Still on top of my previous patch just for safety while testing, as I am
fed up of having to reboot all the time :-)
Doing the flag test in rx_submit seems simpler than trying to track all
the places this is called. Still checking the dev->done.qlen to be able
to unthrottle.
Was this along the lines you thought?
diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 85c7ffd..e3a1d63 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c
@@ -380,6 +382,13 @@ static int rx_submit (struct usbnet *dev, struct urb *urb, gfp_t flags)
unsigned long lockflags;
size_t size = dev->rx_urb_size;
+
+ if (test_bit(EVENT_RX_THROTTLE, &dev->flags) && dev->done.qlen > 0) {
+ netif_dbg(dev, rx_err, dev->net, "%s: EVENT_RX_THROTTLE: (done.qlen=%u)\n", __func__, dev->done.qlen);
+ usb_free_urb(urb);
+ return -ENOLINK;
+ }
+
/* Do not let a device flood us to death! */
if (dev->done.qlen > 1024) {
netif_dbg(dev, rx_err, dev->net, "done queue filling up (%u) - throttling\n", dev->done.qlen);
@@ -482,6 +491,7 @@ static void rx_complete (struct urb *urb)
struct usbnet *dev = entry->dev;
int urb_status = urb->status;
enum skb_state state;
+ static int counter, bogus;
skb_put (skb, urb->actual_length);
state = rx_done;
@@ -547,6 +557,17 @@ block:
break;
}
+ /* keep track of bogus packet ratio */
+ if (++counter > 30) {
+ counter = bogus = 0;
+ clear_bit(EVENT_RX_THROTTLE, &dev->flags);
+ } else {
+ if (state == rx_cleanup)
+ bogus++;
+ if (bogus > counter/2)
+ set_bit(EVENT_RX_THROTTLE, &dev->flags);
+ }
+
state = defer_bh(dev, skb, &dev->rxq, state);
if (urb) {
next prev parent reply other threads:[~2013-01-24 12:48 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-24 10:25 [RFC] net: usbnet: prevent buggy devices from killing us Bjørn Mork
[not found] ` <1359023152-32576-1-git-send-email-bjorn-yOkvZcmFvRU@public.gmane.org>
2013-01-24 10:46 ` Oliver Neukum
[not found] ` <6505263.QGCG9bfoCC-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-01-24 10:52 ` Bjørn Mork
[not found] ` <87bocehmzd.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-24 11:03 ` Oliver Neukum
[not found] ` <2321910.EQLkSoxl50-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-01-24 11:22 ` Bjørn Mork
[not found] ` <877gn2hlkh.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-24 11:31 ` Oliver Neukum
2013-01-24 12:47 ` Bjørn Mork [this message]
[not found] ` <87y5fig32r.fsf-lbf33ChDnrE/G1V5fR+Y7Q@public.gmane.org>
2013-01-24 13:12 ` Oliver Neukum
[not found] ` <2556579.vjYlY1iKn5-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-01-24 13:42 ` Bjørn Mork
2013-01-24 19:16 ` [PATCH net] " Bjørn Mork
2013-01-24 22:09 ` Oliver Neukum
2013-01-25 7:13 ` Bjørn Mork
2013-01-25 12:02 ` Oliver Neukum
[not found] ` <1659086.jLlTU1VIap-7ztolUikljGernLeA6q8OA@public.gmane.org>
2013-01-25 12:27 ` Bjørn Mork
[not found] ` <1359055016-13603-1-git-send-email-bjorn-yOkvZcmFvRU@public.gmane.org>
2013-01-24 23:57 ` Joe Perches
2013-01-25 8:14 ` Bjørn Mork
2013-01-24 10:47 ` [RFC] " Bjørn Mork
2013-01-24 12:39 ` Sergei Shtylyov
[not found] ` <51012B76.1060600-Igf4POYTYCDQT0dZR+AlfA@public.gmane.org>
2013-01-24 13:01 ` Joe Perches
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