diff options
| author | Michael Chan <michael.chan@broadcom.com> | 2018-05-03 20:04:27 -0400 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2018-05-19 10:26:59 +0200 |
| commit | d979320029f97adc7c2112d85fc626a71fe2366a (patch) | |
| tree | 3a9f5a7604baafab784c5405c2b2a64bee241d2a | |
| parent | a9d361cfe203e283a8745d36f9ccde5895237b28 (diff) | |
tg3: Fix vunmap() BUG_ON() triggered from tg3_free_consistent().
[ Upstream commit d89a2adb8bfe6f8949ff389acdb9fa298b6e8e12 ]
tg3_free_consistent() calls dma_free_coherent() to free tp->hw_stats
under spinlock and can trigger BUG_ON() in vunmap() because vunmap()
may sleep. Fix it by removing the spinlock and relying on the
TG3_FLAG_INIT_COMPLETE flag to prevent race conditions between
tg3_get_stats64() and tg3_free_consistent(). TG3_FLAG_INIT_COMPLETE
is always cleared under tp->lock before tg3_free_consistent()
and therefore tg3_get_stats64() can safely access tp->hw_stats
under tp->lock if TG3_FLAG_INIT_COMPLETE is set.
Fixes: f5992b72ebe0 ("tg3: Fix race condition in tg3_get_stats64().")
Reported-by: Zumeng Chen <zumeng.chen@gmail.com>
Signed-off-by: Michael Chan <michael.chan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/net/ethernet/broadcom/tg3.c | 9 |
1 files changed, 5 insertions, 4 deletions
diff --git a/drivers/net/ethernet/broadcom/tg3.c b/drivers/net/ethernet/broadcom/tg3.c index 795a133fb074..4ffbe850d746 100644 --- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c @@ -8720,14 +8720,15 @@ 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); + /* tp->hw_stats can be referenced safely: + * 1. under rtnl_lock + * 2. or under tp->lock if TG3_FLAG_INIT_COMPLETE is set. + */ 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); } /* @@ -14161,7 +14162,7 @@ static struct rtnl_link_stats64 *tg3_get_stats64(struct net_device *dev, struct tg3 *tp = netdev_priv(dev); spin_lock_bh(&tp->lock); - if (!tp->hw_stats) { + if (!tp->hw_stats || !tg3_flag(tp, INIT_COMPLETE)) { *stats = tp->net_stats_prev; spin_unlock_bh(&tp->lock); return stats; |