From: David Oostdyk <daveo@ll•mit.edu>
To: Eric Dumazet <eric.dumazet@gmail•com>
Cc: "netdev@vger•kernel.org" <netdev@vger•kernel.org>,
"macro@linux-mips•org" <macro@linux-mips•org>
Subject: Re: defxx: skb_push() failing?
Date: Tue, 26 Mar 2013 12:03:15 -0400 [thread overview]
Message-ID: <5151C6C3.6090408@ll.mit.edu> (raw)
In-Reply-To: <1364310900.1716.21.camel@edumazet-glaptop>
On 03/26/13 11:15, Eric Dumazet wrote:
> On Tue, 2013-03-26 at 10:29 -0400, David Oostdyk wrote:
>> Hello,
>>
>> In dfx_xmt_queue_pkt() in defxx.c, there is a skb_push(3) call which
>> makes room for 3 packet request header bytes. There is some discussion
>> in the driver explaining why those three bytes will be available. I
>> have an old FDDI card that I'm trying to bring up:
>>
>> 05:05.0 FDDI network controller: Digital Equipment Corporation
>> PCI-to-PDQ Interface Chip [PFI] (rev 02)
>>
>> Most skbuffs that come through dfx_xmit_queue_pkt() have 11 bytes
>> between skb->head and skb->data. On the other hand, at almost exactly
>> 60-second intervals, an skb arrives that has zero bytes between
>> skb->head and skb->data. This normally causes a kernel panic, and for
>> the time I just skip over such skb's.
>>
>> Does anyone have advice on where I should start digging to find the
>> cause of this?
>>
> Have you read comments in defxx.c file around line 151 ?
>
> If one skb arrives with not enough headroom, you could add a
>
> WARN_ON_ONCE(skb_headroom(skb) < 3);
>
> and report stack trace so that we can identify and fix the caller.
>
>
>
I have read the comments, and alloc_fddidev() seems to set the
hard_header_len as described.
As for the stack trace, thanks for the tip! Here is the output
(including various defxx debug statements):
[ 350.312482] defxx: v1.10 2006/12/14 Lawrence V. Stefani and others
[ 350.312582] In dfx_driver_init...
[ 350.312583] In dfx_bus_init...
[ 350.312585] In dfx_bus_config_check...
[ 351.699416] 0000:05:05.0: DEFPA at addr = 0xf9eeff80, IRQ = 26,
Hardware addr = 00-60-b0-58-48-53
[ 351.699425] 0000:05:05.0: Descriptor block virt = FFFF8800CB834000,
phys = CB834000
[ 351.699426] 0000:05:05.0: Command Request buffer virt =
FFFF8800CB835380, phys = CB835380
[ 351.699427] 0000:05:05.0: Command Response buffer virt =
FFFF8800CB835580, phys = CB835580
[ 351.699428] 0000:05:05.0: Receive buffer block virt =
FFFF8800CB835780, phys = CB835780
[ 351.699429] 0000:05:05.0: Consumer block virt = FFFF8800CB835780,
phys = CB835780
[ 351.700049] 0000:05:05.0: registered as fddi0
[ 351.756194] In dfx_open...
[ 351.756215] In dfx_adap_init...
[ 353.927747] fddi0: Multicast address table updated! Added 1 addresses.
[ 353.930352] fddi0: Adapter filters updated!
[ 353.975887] fddi0: Multicast address table updated! Added 1 addresses.
[ 353.978492] fddi0: Adapter filters updated!
[ 354.043455] fddi0: Multicast address table updated! Added 2 addresses.
[ 354.046359] fddi0: Adapter filters updated!
[ 354.097315] fddi0: Multicast address table updated! Added 3 addresses.
[ 354.099919] fddi0: Adapter filters updated!
[ 354.204301] fddi0: Multicast address table updated! Added 3 addresses.
[ 354.207107] fddi0: Adapter filters updated!
[ 354.257972] fddi0: Multicast address table updated! Added 3 addresses.
[ 354.261577] fddi0: Adapter filters updated!
[ 362.976038] ------------[ cut here ]------------
[ 362.976044] WARNING: at drivers/net/fddi/defxx.c:3202
dfx_xmt_queue_pkt+0xa2/0x2f2 [defxx]()
[ 362.976046] Hardware name: Precision WorkStation 490
[ 362.976047] Modules linked in: defxx snd_hda_codec_idt snd_hda_intel
snd_hda_codec snd_hwdep snd_pcm iTCO_wdt snd_page_alloc lpc_ich
snd_timer mfd_core i5000_edac rng_core i2c_i801 fddi rtc_cmos [last
unloaded: defxx]
[ 362.976066] Pid: 1773, comm: aoe_tx Tainted: G I
3.7.10-hippi+ #6
[ 362.976068] Call Trace:
[ 362.976076] [<ffffffff810357e7>] warn_slowpath_common+0x7e/0x96
[ 362.976080] [<ffffffff81035814>] warn_slowpath_null+0x15/0x17
[ 362.976083] [<ffffffffa0063213>] dfx_xmt_queue_pkt+0xa2/0x2f2 [defxx]
[ 362.976088] [<ffffffff813c3401>] ? map_single+0x45/0x45
[ 362.976093] [<ffffffff819175a8>] dev_hard_start_xmit+0x288/0x398
[ 362.976097] [<ffffffff81929d1c>] sch_direct_xmit+0x72/0x19b
[ 362.976100] [<ffffffff819179ec>] dev_queue_xmit+0x145/0x339
[ 362.976105] [<ffffffff8184ab20>] tx+0x1c/0x42
[ 362.976108] [<ffffffff818489a2>] kthread+0x5e/0xbf
[ 362.976113] [<ffffffff81056451>] ? try_to_wake_up+0x239/0x239
[ 362.976116] [<ffffffff81848944>] ? rexmit_timer+0x349/0x349
[ 362.976119] [<ffffffff8104c678>] kthread+0xb5/0xbd
[ 362.976122] [<ffffffff8104c5c3>] ? __kthread_parkme+0x67/0x67
[ 362.976127] [<ffffffff81a314ec>] ret_from_fork+0x7c/0xb0
[ 362.976129] [<ffffffff8104c5c3>] ? __kthread_parkme+0x67/0x67
[ 362.976131] ---[ end trace ce553e95611628f3 ]---
Thanks again for any help!
next prev parent reply other threads:[~2013-03-26 16:03 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-03-26 14:29 defxx: skb_push() failing? David Oostdyk
2013-03-26 15:15 ` Eric Dumazet
2013-03-26 16:03 ` David Oostdyk [this message]
2013-03-26 16:30 ` Eric Dumazet
2013-03-26 18:45 ` David Oostdyk
2013-03-26 19:00 ` Maciej W. Rozycki
2013-03-28 4:11 ` David Oostdyk
2013-03-28 4:28 ` [PATCH] aoe: reserve enough headroom on skbs Eric Dumazet
2013-03-28 18:30 ` David Miller
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=5151C6C3.6090408@ll.mit.edu \
--to=daveo@ll$(echo .)mit.edu \
--cc=eric.dumazet@gmail$(echo .)com \
--cc=macro@linux-mips$(echo .)org \
--cc=netdev@vger$(echo .)kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox