From mboxrd@z Thu Jan  1 00:00:00 1970
From: David Miller <davem@davemloft.net>
Subject: Re: [PATCH] hv_netvsc: fix schedule in RCU context
Date: Thu, 13 Sep 2018 10:30:55 -0700 (PDT)
Message-ID: <20180913.103055.374831883600389403.davem@davemloft.net>
References: <20180913150342.32101-1-sthemmin@microsoft.com>
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Cc: kys@microsoft.com, haiyangz@microsoft.com, netdev@vger.kernel.org,
        sthemmin@microsoft.com
To: stephen@networkplumber.org
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From: Stephen Hemminger <stephen@networkplumber.org>
Date: Thu, 13 Sep 2018 08:03:43 -0700

> When netvsc device is removed it can call reschedule in RCU context.
> This happens because canceling the subchannel setup work could (in theory)
> cause a reschedule when manipulating the timer.
> 
> To reproduce, run with lockdep enabled kernel and unbind
> a network device from hv_netvsc (via sysfs).
 ...
> Resolve this by getting RTNL earlier. This is safe because the subchannel
> work queue does trylock on RTNL and will detect the race.
> 
> Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
> Signed-off-by: Stephen Hemminger <sthemmin@microsoft.com>

Applied and queued up for -stable.