Re: [PATCH net-next] r8152: use mutex for hw settings

From: David Miller
Date: Thu Oct 09 2014 - 19:05:31 EST


From: Hayes Wang <hayeswang@xxxxxxxxxxx>
Date: Thu, 9 Oct 2014 07:59:35 +0000

> If I use the rtnl_lock(), I get a dead lock when enabling autosuspend.
>
> Case 1:
> autosuspend before calling open.
> rtnl_lock()
> call open
> try to autoresume and rtl8152_resume is called.
> dead lock occurs.
>
> Case 2:
> autosuspend occurs.
> rtnl_lock()
> call close
> try to autoresume and rtl8152_resume is called.
> dead lock occurs.

That's really unfortunate that we can variably get into the resume
handlers from contexts holding the RTNL mutex.

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