3.18-stable review patch. If anyone has any objections, please let me know.
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From: Michael Chan michael.chan@broadcom.com
[ 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 --- drivers/net/ethernet/broadcom/tg3.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/net/ethernet/broadcom/tg3.c +++ b/drivers/net/ethernet/broadcom/tg3.c @@ -8705,14 +8705,15 @@ static void tg3_free_consistent(struct t 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); }
/* @@ -14137,7 +14138,7 @@ static struct rtnl_link_stats64 *tg3_get 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;