From: David S. Miller <davem@davemloft.net>
Date: Tue, 9 Jul 2013 19:45:43 +0000 (-0700)
Subject: virtio_net: fix race in RX VQ processing
X-Git-Tag: firefly_0821_release~176^2~5751^2~5
X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=e1d6fbc3dedbb463fc79b48ddb05ab6b20fd088a;p=firefly-linux-kernel-4.4.55.git

virtio_net: fix race in RX VQ processing

Michael S. Tsirkin says:

====================
Jason Wang reported a race in RX VQ processing:
virtqueue_enable_cb is called outside napi lock,
violating virtio serialization rules.
The race has been there from day 1, but it got especially nasty in 3.0
when commit a5c262c5fd83ece01bd649fb08416c501d4c59d7
"virtio_ring: support event idx feature"
added more dependency on vq state.

Please review, and consider for 3.11 and stable.

Changes from v1:
	- Added Jason's Tested-by tag
	- minor coding style fix
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
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e1d6fbc3dedbb463fc79b48ddb05ab6b20fd088a