tg3: Fix race condition in tg3_get_stats64().
authorMichael Chan <michael.chan@broadcom.com>
Fri, 6 Jan 2017 21:18:53 +0000 (16:18 -0500)
committerDavid S. Miller <davem@davemloft.net>
Sun, 8 Jan 2017 02:35:04 +0000 (21:35 -0500)
The driver's ndo_get_stats64() method is not always called under RTNL.
So it can race with driver close or ethtool reconfigurations.  Fix the
race condition by taking tp->lock spinlock in tg3_free_consistent()
when freeing the tp->hw_stats memory block.  tg3_get_stats64() is
already taking tp->lock.

Reported-by: Wang Yufen <wangyufen@huawei.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/broadcom/tg3.c

index 185e9e047aa9adda61ac602caea5f59c3efe2d7e..ae42de4fdddf6b77d2c2cf1606795e139d4b472b 100644 (file)
@@ -8720,11 +8720,14 @@ static void tg3_free_consistent(struct tg3 *tp)
        tg3_mem_rx_release(tp);
        tg3_mem_tx_release(tp);
 
+       /* Protect tg3_get_stats64() from reading freed tp->hw_stats. */
+       tg3_full_lock(tp, 0);
        if (tp->hw_stats) {
                dma_free_coherent(&tp->pdev->dev, sizeof(struct tg3_hw_stats),
                                  tp->hw_stats, tp->stats_mapping);
                tp->hw_stats = NULL;
        }
+       tg3_full_unlock(tp);
 }
 
 /*