fm10k: avoid possible null pointer dereference in fm10k_update_stats

It's currently possible for fm10k_update_stats to be called during the
window when we go down and the rings are removed. This can result in
a null pointer dereference. In fm10k_get_stats64 we work around this by
using ACCESS_ONCE and a null pointer check inside the loop. Use this
same flow in the fm10k_update_stats to avoid the potential null pointer.

Signed-off-by: Jacob Keller <jacob.e.keller@intel.com>
Tested-by: Krishneil Singh <Krishneil.k.singh@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
This commit is contained in:
Jacob Keller 2016-06-03 15:42:12 -07:00 committed by Jeff Kirsher
parent 1b00c6c064
commit b624714bc9

View File

@ -377,7 +377,10 @@ void fm10k_update_stats(struct fm10k_intfc *interface)
/* gather some stats to the interface struct that are per queue */
for (bytes = 0, pkts = 0, i = 0; i < interface->num_tx_queues; i++) {
struct fm10k_ring *tx_ring = interface->tx_ring[i];
struct fm10k_ring *tx_ring = READ_ONCE(interface->tx_ring[i]);
if (!tx_ring)
continue;
restart_queue += tx_ring->tx_stats.restart_queue;
tx_busy += tx_ring->tx_stats.tx_busy;
@ -396,7 +399,10 @@ void fm10k_update_stats(struct fm10k_intfc *interface)
/* gather some stats to the interface struct that are per queue */
for (bytes = 0, pkts = 0, i = 0; i < interface->num_rx_queues; i++) {
struct fm10k_ring *rx_ring = interface->rx_ring[i];
struct fm10k_ring *rx_ring = READ_ONCE(interface->rx_ring[i]);
if (!rx_ring)
continue;
bytes += rx_ring->stats.bytes;
pkts += rx_ring->stats.packets;