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net: renesas: rswitch: handle stop vs interrupt race

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[ Upstream commit 3dd002f20098b9569f8fd7f8703f364571e2e975 ]

Currently the stop routine of rswitch driver does not immediately
prevent hardware from continuing to update descriptors and requesting
interrupts.

It can happen that when rswitch_stop() executes the masking of
interrupts from the queues of the port being closed, napi poll for
that port is already scheduled or running on a different CPU. When
execution of this napi poll completes, it will unmask the interrupts.
And unmasked interrupt can fire after rswitch_stop() returns from
napi_disable() call. Then, the handler won't mask it, because
napi_schedule_prep() will return false, and interrupt storm will
happen.

This can't be fixed by making rswitch_stop() call napi_disable() before
masking interrupts. In this case, the interrupt storm will happen if
interrupt fires between napi_disable() and masking.

Fix this by checking for priv->opened_ports bit when unmasking
interrupts after napi poll. For that to be consistent, move
priv->opened_ports changes into spinlock-protected areas, and reorder
other operations in rswitch_open() and rswitch_stop() accordingly.

Signed-off-by: Nikita Yushchenko <nikita.yoush@cogentembedded.com>
Reviewed-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Fixes: 3590918b5d ("net: ethernet: renesas: Add support for "Ethernet Switch"")
Link: https://patch.msgid.link/20241209113204.175015-1-nikita.yoush@cogentembedded.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Nikita Yushchenko
2024-12-09 16:32:04 +05:00
committed by Greg Kroah-Hartman
parent 92007a28f9
commit 0e01edde25
1 changed files with 18 additions and 15 deletions
Download Patch File Download Diff File Expand all files Collapse all files
drivers/net/ethernet/renesas/rswitch.c
+18 -15
View File
@@ -908,8 +908,10 @@ retry:
if (napi_complete_done(napi, budget - quota)) {
spin_lock_irqsave(&priv->lock, flags);
rswitch_enadis_data_irq(priv, rdev->tx_queue->index, true);
rswitch_enadis_data_irq(priv, rdev->rx_queue->index, true);
if (test_bit(rdev->port, priv->opened_ports)) {
rswitch_enadis_data_irq(priv, rdev->tx_queue->index, true);
rswitch_enadis_data_irq(priv, rdev->rx_queue->index, true);
}
spin_unlock_irqrestore(&priv->lock, flags);
}
@@ -1538,20 +1540,20 @@ static int rswitch_open(struct net_device *ndev)
struct rswitch_device *rdev = netdev_priv(ndev);
unsigned long flags;
phy_start(ndev->phydev);
if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS))
iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDIE);
napi_enable(&rdev->napi);
netif_start_queue(ndev);
spin_lock_irqsave(&rdev->priv->lock, flags);
bitmap_set(rdev->priv->opened_ports, rdev->port, 1);
rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, true);
rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, true);
spin_unlock_irqrestore(&rdev->priv->lock, flags);
if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS))
iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDIE);
phy_start(ndev->phydev);
bitmap_set(rdev->priv->opened_ports, rdev->port, 1);
netif_start_queue(ndev);
return 0;
};
@@ -1563,7 +1565,16 @@ static int rswitch_stop(struct net_device *ndev)
unsigned long flags;
netif_tx_stop_all_queues(ndev);
phy_stop(ndev->phydev);
spin_lock_irqsave(&rdev->priv->lock, flags);
rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false);
rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false);
bitmap_clear(rdev->priv->opened_ports, rdev->port, 1);
spin_unlock_irqrestore(&rdev->priv->lock, flags);
napi_disable(&rdev->napi);
if (bitmap_empty(rdev->priv->opened_ports, RSWITCH_NUM_PORTS))
iowrite32(GWCA_TS_IRQ_BIT, rdev->priv->addr + GWTSDID);
@@ -1576,14 +1587,6 @@ static int rswitch_stop(struct net_device *ndev)
kfree(ts_info);
}
spin_lock_irqsave(&rdev->priv->lock, flags);
rswitch_enadis_data_irq(rdev->priv, rdev->tx_queue->index, false);
rswitch_enadis_data_irq(rdev->priv, rdev->rx_queue->index, false);
spin_unlock_irqrestore(&rdev->priv->lock, flags);
phy_stop(ndev->phydev);
napi_disable(&rdev->napi);
return 0;
};