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Commit 3293c85b authored by Michael Chan's avatar Michael Chan Committed by Greg Kroah-Hartman
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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: default avatarZumeng Chen <zumeng.chen@gmail.com>
Signed-off-by: default avatarMichael Chan <michael.chan@broadcom.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent defbbf4c

drivers/net/ethernet/broadcom/tg3.c

+5 −4
Original line number Original line Diff line number Diff line
@@ -8705,14 +8705,15 @@ static void tg3_free_consistent(struct tg3 *tp) 
	tg3_mem_rx_release(tp);

	tg3_mem_rx_release(tp);

	tg3_mem_tx_release(tp);

	tg3_mem_tx_release(tp);





	/* Protect tg3_get_stats64() from reading freed tp->hw_stats. */

	/* tp->hw_stats can be referenced safely:

	tg3_full_lock(tp, 0);

	 *     1. under rtnl_lock

	 *     2. or under tp->lock if TG3_FLAG_INIT_COMPLETE is set.

	 */

	if (tp->hw_stats) {

	if (tp->hw_stats) {

		dma_free_coherent(&tp->pdev->dev, sizeof(struct tg3_hw_stats),

		dma_free_coherent(&tp->pdev->dev, sizeof(struct tg3_hw_stats),

				  tp->hw_stats, tp->stats_mapping);

				  tp->hw_stats, tp->stats_mapping);

		tp->hw_stats = NULL;

		tp->hw_stats = NULL;

	}

	}

	tg3_full_unlock(tp);

}

}





/*

/*
@@ -14137,7 +14138,7 @@ static struct rtnl_link_stats64 *tg3_get_stats64(struct net_device *dev, 
	struct tg3 *tp = netdev_priv(dev);

	struct tg3 *tp = netdev_priv(dev);





	spin_lock_bh(&tp->lock);

	spin_lock_bh(&tp->lock);

	if (!tp->hw_stats) {

	if (!tp->hw_stats || !tg3_flag(tp, INIT_COMPLETE)) {

		*stats = tp->net_stats_prev;

		*stats = tp->net_stats_prev;

		spin_unlock_bh(&tp->lock);

		spin_unlock_bh(&tp->lock);

		return stats;

		return stats;