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Date: Sun, 7 Jul 2013 17:32:26 +0800
Message-ID: <CACVXFVOYOhHKy4Ej5V5+d0atGRn7x5RVT55joWD+ndR2ASqpfw@mail.gmail.com>
Subject: Re: inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage with hcd_urb_list_lock
From: Ming Lei <tom.leiming@gmail.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Sarah Sharp <sarah.a.sharp@linux.intel.com>,
        Maarten Lankhorst <m.b.lankhorst@gmail.com>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        USB list <linux-usb@vger.kernel.org>
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On Sun, Jul 7, 2013 at 4:48 AM, Alan Stern <stern@rowland.harvard.edu> wrote:
> On Sat, 6 Jul 2013, Maarten Lankhorst wrote:
>
>> I didn't even know I still had lockdep on.
>> The following lockdep splat happened when I plugged in a usb bluetooth dongle, using
>> the pre-rc1 3.11 kernel at HEAD b2c311075db
>>
>> =================================
>> [ INFO: inconsistent lock state ]
>> 3.10.0+ #106 Not tainted
>> ---------------------------------
>> inconsistent {IN-HARDIRQ-W} -> {HARDIRQ-ON-W} usage.
>> irq/42-xhci_hcd/97 [HC0[0]:SC0[2]:HE1:SE0] takes:
>>  (hcd_urb_list_lock){?.....}, at: [<ffffffff8149440e>] usb_hcd_unlink_urb_from_ep+0x28/0x4e
>
>> stack backtrace:
>> CPU: 1 PID: 97 Comm: irq/42-xhci_hcd Not tainted 3.10.0+ #106

Maarten, I am wondering you are running kernel from linus tree since
looks xhci threaded irq is enabled from the log.

If yes, please don't do that because USB host controller driver still
doesn't support threaded irq now.

>> Hardware name: Acer Aspire M3985/Aspire M3985, BIOS P01-A1 03/12/2012
>>  ffffffff8210c150 ffff88040834da48 ffffffff81691af4 0000000000000007
>>  ffff8804082e20b0 ffff88040834daa8 ffffffff8168cb10 0000000000000002
>>  ffff880400000001 ffff880400000000 ffffffff8100f4f7 ffff88040834dac4
>> Call Trace:
>>  [<ffffffff81691af4>] dump_stack+0x4f/0x84
>>  [<ffffffff8168cb10>] print_usage_bug+0x1f5/0x206
>>  [<ffffffff8100f4f7>] ? save_stack_trace+0x2f/0x50
>>  [<ffffffff810af30c>] mark_lock+0x276/0x2cf
>>  [<ffffffff810ae8cc>] ? check_usage_forwards+0x12f/0x12f
>>  [<ffffffff810af925>] __lock_acquire+0x5c0/0x1c2e
>>  [<ffffffff810b1e04>] ? mark_held_locks+0x6d/0x117
>>  [<ffffffff8168e8d4>] ? __slab_free+0x1c7/0x2ed
>>  [<ffffffff810b1f5a>] ? trace_hardirqs_on_caller+0xac/0x1bb
>>  [<ffffffff810b2076>] ? trace_hardirqs_on+0xd/0xf
>>  [<ffffffff8149440e>] ? usb_hcd_unlink_urb_from_ep+0x28/0x4e
>>  [<ffffffff810b1556>] lock_acquire+0x87/0x139
>>  [<ffffffff8149440e>] ? usb_hcd_unlink_urb_from_ep+0x28/0x4e
>>  [<ffffffff81698a1a>] _raw_spin_lock+0x3b/0x4a
>>  [<ffffffff8149440e>] ? usb_hcd_unlink_urb_from_ep+0x28/0x4e
>>  [<ffffffff8149440e>] usb_hcd_unlink_urb_from_ep+0x28/0x4e
>>  [<ffffffff814bf55a>] xhci_irq+0x5ac/0x143d
>>  [<ffffffff81699171>] ? _raw_spin_unlock_irq+0x3b/0x5d
>>  [<ffffffff8108386d>] ? finish_task_switch+0x7c/0x101
>>  [<ffffffff81083830>] ? finish_task_switch+0x3f/0x101
>>  [<ffffffff81697060>] ? __schedule+0x42a/0x885
>>  [<ffffffff810d7fdb>] ? irq_thread_fn+0x48/0x48
>>  [<ffffffff814c03fc>] xhci_msi_irq+0x11/0x15
>
> It looks like xhci_msi_irq() needs to call local_irq_save() and
> local_irq_restore().

Looks it isn't needed.

Thanks,
-- 
Ming Lei
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