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From: "Michał Nazarewicz" <m.nazarewicz@samsung.com>
To: linux-usb@vger.kernel.org, netdev@vger.kernel.org,
	Neil Jones <neiljay@gmail.com>
Subject: Re: rndis gadget: Inconsistent locking
Date: Wed, 08 Dec 2010 18:15:57 +0100	[thread overview]
Message-ID: <op.vnenkvz67p4s8u@pikus> (raw)
In-Reply-To: <AANLkTi==UqNNzokLcLWDpjM0cqM6aXjppsi4p6ogMAqX@mail.gmail.com>

On Wed, 08 Dec 2010 16:11:30 +0100, Neil Jones <neiljay@gmail.com> wrote:
> Im getting another lockdep warning when using the RNDIS gadget:
>
>  WARNING: at kernel/softirq.c:98 ___local_bh_disable+0xc4/0xd0()
>  Modules linked in: g_ether
>
>  Call trace:
>  [<40003bf8>] _show_stack+0x68/0x7c
>  [<40003c20>] _dump_stack+0x14/0x28
>  [<40013c3c>] _warn_slowpath_common+0x5c/0x7c
>  [<40013c74>] _warn_slowpath_null+0x18/0x2c
>  [<4001b17c>] ___local_bh_disable+0xc0/0xd0
>  [<4001b1a0>] _local_bh_disable+0x14/0x28
>  [<402e57f8>] __raw_spin_lock_bh+0x18/0x54
>  [<40257f4c>] _dev_txq_stats_fold+0x7c/0x13c
>  [<402580c4>] _dev_get_stats+0xb8/0xc0
>  [<781d4e60>] _rndis_msg_parser+0x288/0xa04 [g_ether]
>  [<781d5600>] _rndis_command_complete+0x24/0x70 [g_ether]
>  [<401d66fc>] _dwc_otg_request_done+0xd8/0x220
>  [<401d928c>] _ep0_complete_request+0x3f4/0x578
>  [<401d95bc>] _handle_ep0+0x1ac/0x146c
>  [<401daf7c>] _dwc_otg_pcd_handle_in_ep_intr+0x1c0/0x8bc
>  [<401db8dc>] _dwc_otg_pcd_handle_intr+0x264/0x294
>  [<401d6288>] _dwc_otg_pcd_irq+0x10/0x30
>  [<40054cf4>] _handle_IRQ_event+0x4c/0x184
>  [<40057b4c>] _handle_level_irq+0xac/0x15c
>  [<4000b204>] _metag_soc_irq_demux+0xac/0xb4
>  [<40002dd4>] _do_IRQ+0x4c/0x78
>  [<40004000>] _trigger_handler+0x38/0xac
>  [<40000b18>] ___TBIBoingVec+0xc/0x10
>  [<40003588>] _cpu_idle+0x54/0x78
>
>  no locks held by swapper/0.
>  ---[ end trace 77ac3cfee0ae5b25 ]---

Known problem.

> It looks like we are calling spin_lock_bh in the completion function
> which is running in hard_irq, I think the driver should defer handling
> this msg (and maybe all requests) to a workqueue?

Does this help: <https://patchwork.kernel.org/patch/195562/>?

-- 
Best regards,                                        _     _
| Humble Liege of Serenely Enlightened Majesty of  o' \,=./ `o
| Computer Science,  Michał "mina86" Nazarewicz       (o o)
+----[mina86*mina86.com]---[mina86*jabber.org]----ooO--(_)--Ooo--

  reply	other threads:[~2010-12-08 17:16 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-12-08 15:03 rndis gadget: Inconsistent locking Neil Jones
2010-12-08 15:11 ` Neil Jones
2010-12-08 17:15   ` Michał Nazarewicz [this message]
2010-12-09 17:00     ` Neil Jones
     [not found]       ` <AANLkTinE1srqkpib0+8Q63XjnhRYEWaaDsX70tc_OeUm-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-10 10:01         ` Michał Nazarewicz
     [not found]   ` <AANLkTi==UqNNzokLcLWDpjM0cqM6aXjppsi4p6ogMAqX-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2010-12-26 23:49     ` David Brownell
2011-01-07  9:30       ` Neil Jones
2011-01-07 11:20         ` David Brownell
2011-01-10 11:32           ` Neil Jones
2011-01-10 12:14             ` David Brownell
2011-01-12 12:28               ` Jarek Poplawski
     [not found]                 ` <20110112122811.GA9513-8HppEYmqbBCE+EvaaNYduQ@public.gmane.org>
2011-01-12 13:07                   ` Eric Dumazet
2011-01-12 13:23                     ` Jarek Poplawski
2011-01-12 13:32                       ` Eric Dumazet
2011-01-12 13:41                         ` Jarek Poplawski
2011-01-12 13:52                         ` Eric Dumazet
2011-01-12 15:02                           ` [PATCH] net: remove dev_txq_stats_fold() Eric Dumazet
2011-01-12 21:05                             ` Jarek Poplawski
     [not found]                               ` <20110112210518.GA2152-qLhEM4ewh5CNj9Bq2fkWzw@public.gmane.org>
2011-01-12 21:18                                 ` Jarek Poplawski
2011-01-12 22:13                                   ` Eric Dumazet
2011-01-14  5:45                                     ` David Miller

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