Re: 2.6.17-mm6

[Stefan Richter <stefanr@s5r6.in-berlin.de>]

On 7/4/2006 10:01 PM, Arjan van de Ven wrote:
> this is one for the networking people, and thus netdev

It's actually ieee1394 using net infrastructure for purposes which ar
unrelated to networking.

Furthermore...

> On Tue, 2006-07-04 at 21:53 +0200, Rafael J. Wysocki wrote:
>> On Monday 03 July 2006 12:03, Andrew Morton wrote:
>> > ftp://ftp.kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.17/2.6.17-mm6/
>> > 
>> > - A major update to the e1000 driver.
>> > - 1394 updates

...I believe it is unrelated to the 1394 updates new to -mm6.

>> Just found this in dmesg:
>> 
>> =================================
>> [ INFO: inconsistent lock state ]
>> ---------------------------------
>> inconsistent {in-hardirq-W} -> {hardirq-on-W} usage.
>> nscd/4929 [HC0[0]:SC0[1]:HE1:SE0] takes:
>>  (&skb_queue_lock_key){++..}, at: [<ffffffff8044fe40>] udp_ioctl+0x50/0xa0
>> {in-hardirq-W} state was registered at:
>>   [<ffffffff8024b4fa>] lock_acquire+0x8a/0xc0
>>   [<ffffffff80476e3f>] _spin_lock_irqsave+0x3f/0x60
>>   [<ffffffff80408c25>] skb_queue_tail+0x25/0x60
> 
> ok so skb_queue_lock is used in a hardirq context
> 
>>   [<ffffffff881c9517>] queue_packet_complete+0x27/0x40 [ieee1394]
>>   [<ffffffff881c9d6b>] hpsb_packet_sent+0xab/0x100 [ieee1394]
>>   [<ffffffff8822a4b5>] dma_trm_reset+0x115/0x140 [ohci1394]
>>   [<ffffffff8822c512>] ohci_devctl+0x1c2/0x540 [ohci1394]
>>   [<ffffffff881c9673>] hpsb_bus_reset+0x43/0xb0 [ieee1394]
>>   [<ffffffff8822d7f6>] ohci_irq_handler+0x416/0x830 [ohci1394]
>>   [<ffffffff802631ab>] handle_IRQ_event+0x2b/0x70
>>   [<ffffffff80264dd4>] handle_level_irq+0xc4/0x130
>>   [<ffffffff8020c762>] do_IRQ+0x112/0x130
>>   [<ffffffff80209d90>] common_interrupt+0x64/0x65
>> irq event stamp: 4280
>> hardirqs last  enabled at (4279): [<ffffffff8047606a>] trace_hardirqs_on_thunk+0x35/0x37
>> hardirqs last disabled at (4278): [<ffffffff804760a1>] trace_hardirqs_off_thunk+0x35/0x67
>> softirqs last  enabled at (4258): [<ffffffff804065b5>] release_sock+0xd5/0xe0
>> softirqs last disabled at (4280): [<ffffffff804764d1>] _spin_lock_bh+0x11/0x50
>> 
>> other info that might help us debug this:
>> no locks held by nscd/4929.
>> 
>> stack backtrace:
>> 
>> Call Trace:
>>  [<ffffffff8020ab9f>] show_trace+0x9f/0x240
>>  [<ffffffff8020af75>] dump_stack+0x15/0x20
>>  [<ffffffff80249e52>] print_usage_bug+0x272/0x290
>>  [<ffffffff8024a0d7>] mark_lock+0x267/0x5f0
>>  [<ffffffff8024a9a6>] __lock_acquire+0x546/0xd10
>>  [<ffffffff8024b4fb>] lock_acquire+0x8b/0xc0
>>  [<ffffffff804764f4>] _spin_lock_bh+0x34/0x50
>>  [<ffffffff8044fe40>] udp_ioctl+0x50/0xa0
> 
> yet udp_ioctl takes it only for _bh
> 
>>  [<ffffffff80457359>] inet_ioctl+0x69/0x70
>>  [<ffffffff804033ac>] sock_ioctl+0x22c/0x270
>>  [<ffffffff802a32b1>] do_ioctl+0x31/0xa0
>>  [<ffffffff802a35db>] vfs_ioctl+0x2bb/0x2e0
>>  [<ffffffff802a366a>] sys_ioctl+0x6a/0xa0
>>  [<ffffffff8020985a>] system_call+0x7e/0x83
>>  [<00002b2d76ab98a9>]
> 
> is this a real scenario, or is this a case of "firewire is special and
> needs it's own rules"?

Well, firewire is special, but that should already be addressed by this
patch: "lockdep: annotate ieee1394 skb-queue-head locking"
http://kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff_plain;h=d378834840907326ac9d448056d957d13cc3718f

Why is there still a lockdep warning?

(Ieee1394 core's usage of the skb_* API is entirely unrelated to
networking; even if eth1394 was used.)
-- 
Stefan Richter
-=====-=-==- -=== --=-=
http://arcgraph.de/sr/
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