Re: [GIT] Networking

Geert Uytterhoeven
2014-06-13T07:21:10Z

On Fri, Jun 13, 2014 at 8:59 AM, Johannes Berg
<johannes@sipsolutions.net> wrote:
> On Fri, 2014-06-13 at 06:48 +0000, Linus Torvalds wrote:
>> On Thu, Jun 12, 2014 at 12:14 PM, David Miller <davem@davemloft.net> wrote:
>> >
>> > git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next.git master
>>
>> Hmm. I get *lots* of the appended messages from iwlwifi now. Things
>> still seem to work, but ...
>>
>> This is a Haswell laptop with bog-standard intel wireless:
>>
>> 01:00.0 Network controller: Intel Corporation Wireless 7260 (rev 6b)
>>
>> Any ideas?
>
> Looks odd.
>
> If the stacktrace/message
>
>> [ 273.783438] <unknown>: hw csum failure
>> [ 273.783449] CPU: 2 PID: 2199 Comm: Chrome_IOThread Not tainted 3.15.0-11906-g6d87c225f5d8 #8
>> [ 273.783451] Hardware name: Sony Corporation SVP11213CXB/VAIO, BIOS R0270V7 05/17/2013
>> [ 273.783461] Call Trace:
>> [ 273.783477] [<ffffffff8159d199>] ? dump_stack+0x41/0x51
>> [ 273.783488] [<ffffffff814a4f1d>] ? skb_copy_and_csum_datagram_iovec+0xfd/0x110
>> [ 273.783494] [<ffffffff8150e2ea>] ? udp_recvmsg+0x1ca/0x390
>> [ 273.783500] [<ffffffff81518e95>] ? inet_recvmsg+0x65/0x80
>> [ 273.783506] [<ffffffff814971f5>] ? sock_recvmsg+0x95/0xd0
>> [ 273.783511] [<ffffffff81197862>] ? ep_send_events_proc+0xa2/0x1b0
>> [ 273.783513] [<ffffffff811977c0>] ? ep_read_events_proc+0xb0/0xb0
>> [ 273.783516] [<ffffffff81497325>] ? SYSC_recvfrom+0xb5/0x110
>> [ 273.783521] [<ffffffff8108bdc0>] ? wake_up_state+0x10/0x10
>> [ 273.783527] [<ffffffff815a3d92>] ? system_call_fastpath+0x16/0x1b
>
> is to be believed, then I'm not sure why you think iwlwifi is involved
> though.
>
> Either way, iwlwifi doesn't support HW checksumming, so it failing makes
> no sense, it's not there to start with.
>
> The only thing that touched this seems to be Tom's patch:
>
> commit 7e3cead5172927732f51fde77fef6f521e22f209
> Author: Tom Herbert <therbert@google.com>
> Date: Tue Jun 10 18:54:19 2014 -0700
>
> net: Save software checksum complete
>
> but I'm not familiar enough to say where this leads.
>
> If it's iwlwifi, then maybe that commit broke something with devices
> that don't support checksumming?

Tom posted some fixes for this:
http://marc.info/?l=linux-netdev&m=140261417832399&w=2

I can confirm the first one fixes the issue I was having (10s delay in
ssh login), cfr. http://marc.info/?l=linux-netdev&m=140257250715322&w=2

However, the second patch reintroduces the bad behavior again?

Gr{oetje,eeting}s,

Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds