Re: sleeping while atomic in dwc3_gadget_start

[Stephen Boyd]

On 06/28/13 03:58, Felipe Balbi wrote:
> Hi,
>
> On Thu, Jun 27, 2013 at 09:57:52AM -0700, Stephen Boyd wrote:
>> On 06/26/13 23:58, Felipe Balbi wrote:
>>> On Wed, Jun 26, 2013 at 02:52:56PM -0700, Stephen Boyd wrote:
>>>> Hi,
>>>>
>>>> I'm getting the folllowing BUG message on bootup with 3.10-rc5
>>>>
>>>> BUG: sleeping function called from invalid context at mm/slub.c:926
>>>> in_atomic(): 1, irqs_disabled(): 128, pid: 1, name: swapper/0
>>>> CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.10.0-rc5-gee3e35b-09316-ge78f3b35 #643
>>>> [<c0014220>] (unwind_backtrace+0x0/0x120) from [<c001212c>] (show_stack+0x10/0x14)
>>>> [<c001212c>] (show_stack+0x10/0x14) from [<c0143750>] (kmem_cache_alloc_trace+0x3c/0x210)
>>>> [<c0143750>] (kmem_cache_alloc_trace+0x3c/0x210) from [<c00e0c60>] (request_threaded_irq+0x88/0x11c)
>>>> [<c00e0c60>] (request_threaded_irq+0x88/0x11c) from [<c03bf53c>] (dwc3_gadget_start+0x198/0x200)
>>>> [<c03bf53c>] (dwc3_gadget_start+0x198/0x200) from [<c03f7a5c>] (udc_bind_to_driver+0x70/0xd8)
>>>> [<c03f7a5c>] (udc_bind_to_driver+0x70/0xd8) from [<c03f7b50>] (usb_gadget_probe_driver+0x8c/0xb8)
>>>>
>>>> and I suspect this problem was introduced in commit 8698e2acf
>>>> (usb: dwc3: gadget: introduce and use enable/disable irq
>>>> methods). Is there a fix for this problem? Can we just move the
>>>> irq request outside the spinlock?
>>> nice :-)
>>>
>>> how about this ?
>> If start fails do you call stop? I believe the answer is no, so we'll
>> need to free_irq() somewhere along the error path. Or we can request it
>> after the spin_unlock()?
> good point here's v2:

Ok looks good to me. I hope that platform_get_irq() doesn't fail,
otherwise we're in for a nasty surprise. Maybe we should add a check in
request_irq() for that case.

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