* Re: 3.9.5+: Crash in tcp_input.c:4810.
[not found] ` <1373314235.4979.121.camel@edumazet-glaptop>
@ 2013-07-08 20:17 ` Ben Greear
0 siblings, 0 replies; only message in thread
From: Ben Greear @ 2013-07-08 20:17 UTC (permalink / raw)
To: Eric Dumazet; +Cc: netdev, linux-wireless@vger.kernel.org
On 07/08/2013 01:10 PM, Eric Dumazet wrote:
> On Mon, 2013-07-08 at 12:59 -0700, Ben Greear wrote:
>
>>> There is this thing in ath9k about aggregating two frags
>>>
>>> drivers/net/wireless/ath/ath9k/recv.c line 1298 contains :
>>>
>>> RX_STAT_INC(rx_frags);
>>>
>>> Could you check these stats (I do not know if they are reported by
>>> ethtool -S or another debugging facility) and check if rx_frags is ever
>>> increasing ?
>>
>> They are in debugfs, and they appear to increase fairly often, for
>> instance:
>>
>> [root@lec2010-ath9k-1 lanforge]# cat /debug/ieee80211/wiphy0/ath9k/recv|tail -5
>> RX-Pkts-All : 288009442
>> RX-Bytes-All : 4067932166
>> RX-Beacons : 14826735
>> RX-Frags : 3944
>> RX-Spectral : 0
>>
>> I don't have the stats from the system that reproduced the bug
>> (it has been rebooted), but if I do see the bug again, I'll
>> grab the rx-frags and other stats just in case it shows
>> some anomaly.
>>
>
> Reading this code again, I believe following patch is needed.
>
> Could you test it ?
Sure, will do. Adding the linux-wireless mailing list as well.
Thanks,
Ben
>
> Thanks
>
> diff --git a/drivers/net/wireless/ath/ath9k/recv.c b/drivers/net/wireless/ath/ath9k/recv.c
> index 8be2b5d..f642f04 100644
> --- a/drivers/net/wireless/ath/ath9k/recv.c
> +++ b/drivers/net/wireless/ath/ath9k/recv.c
> @@ -1317,7 +1317,8 @@ int ath_rx_tasklet(struct ath_softc *sc, int flush, bool hp)
> if (sc->rx.frag) {
> int space = skb->len - skb_tailroom(hdr_skb);
>
> - if (pskb_expand_head(hdr_skb, 0, space, GFP_ATOMIC) < 0) {
> + if (space > 0 &&
> + pskb_expand_head(hdr_skb, 0, space, GFP_ATOMIC) < 0) {
> dev_kfree_skb(skb);
> RX_STAT_INC(rx_oom_err);
> goto requeue_drop_frag;
>
--
Ben Greear <greearb@candelatech.com>
Candela Technologies Inc http://www.candelatech.com
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