From: Jacob Keller Date: Fri, 3 Jun 2016 22:42:12 +0000 (-0700) Subject: fm10k: avoid possible null pointer dereference in fm10k_update_stats X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=b624714bc90064eeefd9ba7564e90865eef00421;p=deliverable%2Flinux.git 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 Tested-by: Krishneil Singh Signed-off-by: Jeff Kirsher --- diff --git a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c index 610c313610c8..be0b7dea6e72 100644 --- a/drivers/net/ethernet/intel/fm10k/fm10k_pci.c +++ b/drivers/net/ethernet/intel/fm10k/fm10k_pci.c @@ -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;