Re: ath5k AP kernel panic when client uses SCP

From: Tomasz Chmielewski
Date: Sat Oct 24 2009 - 11:28:33 EST

Bob Copeland wrote:

[ 516.430000] ------------[ cut here ]------------
[ 516.430000] WARNING: at net/core/dev.c:1566 skb_gso_segment+0x110/0x298()
[ 516.440000] b44: caps=(0x0, 0x0) len=52 data_len=0 ip_summed=1

So this looks like the ethernet driver b44 instead of ath5k, I think.

Could be, but!

I can trigger it when doing this kind of SSH traffic:

PC >--100Mbit--> b44 (Asus WL-500gP) ath5k >--wireless--> laptop

When I transfer over wired ethernet only through this device, everything works properly, no page allocation failures, no warnings, panics.

[ 516.450000] Modules linked in: configs aes_generic tun sch_sfq cls_fw sch_htb ipt_MASQUERADE iptable_nat nf_nat xt_MARK iptable_mangle ipt_ULOG xt_recent nf_conn1
[ 516.480000] Call Trace:
[ 516.480000] [<80013ac4>] dump_stack+0x8/0x34
[ 516.480000] [<8002f2a0>] warn_slowpath_common+0x70/0x98
[ 516.490000] [<8002f308>] warn_slowpath_fmt+0x24/0x30
[ 516.490000] [<801f0398>] skb_gso_segment+0x110/0x298

...but this is higher up the stack. skb_gso_segment is about a year old
so it would be odd if there were a bug here. Can you do the following?

objdump -S net/core/dev.o, then find the address for skb_gso_segment, it should look something like this (your numbers and disassembly will

00004190 <skb_gso_segment>:
* It may return NULL if the skb requires no segmentation. This is
* only possible when GSO is used for verifying header integrity.

Hmm, I get:

00000000 <skb_gso_segment>

So I better leave the files here:

Let me know if you need anything else.

Tomasz Chmielewski
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