Re: 2.6.34 Crash in dmaengine_put()

[Jeffrey Merkey]

OK.  This bug occurs if you OR in the IFF_UP flag while creating
virtual interfaces without going through the normal ifup/ifdown
scripts.  Looks like a hole.  I will post the trace shortly.  It's
easy to reproduce, take the dummy net driver, OR in the IFF_UP flag in
dummy_setup, and watch the kernel crash.

Jeff

On Mon, Jun 21, 2010 at 9:28 PM, Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
> On Mon, 21 Jun 2010 20:57:40 -0600 Jeffrey Merkey <jeffmerkey@xxxxxxxxx> wrote:
>
>> If someone sets the IFF_UP flags in the netdev structure without going
>> through ifup userspace stuff, during unregister of the the netdev
>> the dmaengine-put code will decrement the reference counter negative,
>> and crash at BUG! in the driver/dma/dmaengine.c code.  This seems
>> busted.
>>
>
> Please send a copy of the kernel BUG trace.
>
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