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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Ciara Loftus <ciara.loftus@intel.com>,
        Andrew Bowers <andrewx.bowers@intel.com>,
        Jeff Kirsher <jeffrey.t.kirsher@intel.com>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 5.7 024/166] ice: protect ring accesses with WRITE_ONCE
Date:   Tue, 14 Jul 2020 20:43:09 +0200
Message-Id: <20200714184117.038430264@linuxfoundation.org>
In-Reply-To: <20200714184115.844176932@linuxfoundation.org>
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From: Ciara Loftus <ciara.loftus@intel.com>

[ Upstream commit b1d95cc2391ffac0c5b27256a4fb0d2cfb021a29 ]

The READ_ONCE macro is used when reading rings prior to accessing the
statistics pointer. The corresponding WRITE_ONCE usage when allocating and
freeing the rings to ensure protected access was not in place. Introduce
this.

Signed-off-by: Ciara Loftus <ciara.loftus@intel.com>
Tested-by: Andrew Bowers <andrewx.bowers@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/ethernet/intel/ice/ice_lib.c  | 8 ++++----
 drivers/net/ethernet/intel/ice/ice_main.c | 2 +-
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ethernet/intel/ice/ice_lib.c b/drivers/net/ethernet/intel/ice/ice_lib.c
index 2f256bf45efcf..6dd839b325259 100644
--- a/drivers/net/ethernet/intel/ice/ice_lib.c
+++ b/drivers/net/ethernet/intel/ice/ice_lib.c
@@ -1063,7 +1063,7 @@ static void ice_vsi_clear_rings(struct ice_vsi *vsi)
 		for (i = 0; i < vsi->alloc_txq; i++) {
 			if (vsi->tx_rings[i]) {
 				kfree_rcu(vsi->tx_rings[i], rcu);
-				vsi->tx_rings[i] = NULL;
+				WRITE_ONCE(vsi->tx_rings[i], NULL);
 			}
 		}
 	}
@@ -1071,7 +1071,7 @@ static void ice_vsi_clear_rings(struct ice_vsi *vsi)
 		for (i = 0; i < vsi->alloc_rxq; i++) {
 			if (vsi->rx_rings[i]) {
 				kfree_rcu(vsi->rx_rings[i], rcu);
-				vsi->rx_rings[i] = NULL;
+				WRITE_ONCE(vsi->rx_rings[i], NULL);
 			}
 		}
 	}
@@ -1104,7 +1104,7 @@ static int ice_vsi_alloc_rings(struct ice_vsi *vsi)
 		ring->vsi = vsi;
 		ring->dev = dev;
 		ring->count = vsi->num_tx_desc;
-		vsi->tx_rings[i] = ring;
+		WRITE_ONCE(vsi->tx_rings[i], ring);
 	}
 
 	/* Allocate Rx rings */
@@ -1123,7 +1123,7 @@ static int ice_vsi_alloc_rings(struct ice_vsi *vsi)
 		ring->netdev = vsi->netdev;
 		ring->dev = dev;
 		ring->count = vsi->num_rx_desc;
-		vsi->rx_rings[i] = ring;
+		WRITE_ONCE(vsi->rx_rings[i], ring);
 	}
 
 	return 0;
diff --git a/drivers/net/ethernet/intel/ice/ice_main.c b/drivers/net/ethernet/intel/ice/ice_main.c
index 69e50331e08e9..7fd2ec63f128e 100644
--- a/drivers/net/ethernet/intel/ice/ice_main.c
+++ b/drivers/net/ethernet/intel/ice/ice_main.c
@@ -1701,7 +1701,7 @@ static int ice_xdp_alloc_setup_rings(struct ice_vsi *vsi)
 		xdp_ring->netdev = NULL;
 		xdp_ring->dev = dev;
 		xdp_ring->count = vsi->num_tx_desc;
-		vsi->xdp_rings[i] = xdp_ring;
+		WRITE_ONCE(vsi->xdp_rings[i], xdp_ring);
 		if (ice_setup_tx_ring(xdp_ring))
 			goto free_xdp_rings;
 		ice_set_ring_xdp(xdp_ring);
-- 
2.25.1