https://github.com/torvalds/linux
Revision a8ceb5dbfde1092b466936bca0ff3be127ecf38e authored by Michael S. Tsirkin on 05 December 2017, 19:29:37 UTC, committed by David S. Miller on 11 December 2017, 15:52:23 UTC
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@cavium.com> Suggested-by: Jason Wang <jasowang@redhat.com> Signed-off-by: Michael S. Tsirkin <mst@redhat.com> Acked-by: Jason Wang <jasowang@redhat.com> Signed-off-by: David S. Miller <davem@davemloft.net>
1 parent f0f1d01
Tip revision: a8ceb5dbfde1092b466936bca0ff3be127ecf38e authored by Michael S. Tsirkin on 05 December 2017, 19:29:37 UTC
ptr_ring: add barriers
ptr_ring: add barriers
Tip revision: a8ceb5d
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