Hi David,
On 12/11/2017 09:23 PM, David Miller wrote:
From: "Michael S. Tsirkin" <mst@xxxxxxxxxx>
Date: Tue, 5 Dec 2017 21:29:37 +0200
Users of ptr_ring expect that it's safe to give the
data structure a pointer and have it be available
to consumers, but that actually requires an smb_wmb
or a stronger barrier.
In absence of such barriers and on architectures that reorder writes,
consumer might read an un=initialized value from an skb pointer stored
in the skb array. This was observed causing crashes.
To fix, add memory barriers. The barrier we use is a wmb, the
assumption being that producers do not need to read the value so we do
not need to order these reads.
Reported-by: George Cherian <george.cherian@xxxxxxxxxx>
Suggested-by: Jason Wang <jasowang@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
I'm asked for asking for testing feedback and did not get it in a
reasonable amount of time.
The tests have completed more than 48 hours without any failures.
I won't interrupt the same and run for longer time.
In case of any issue I will report the same.
So I'm applying this as-is, and queueing it up for -stable.
Thank you.
Regards,
-George
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