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Date: Wed, 15 Nov 2023 11:26:44 +0900
From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
To: s.shtylyov@....ru,
davem@...emloft.net,
edumazet@...gle.com,
kuba@...nel.org,
pabeni@...hat.com
Cc: netdev@...r.kernel.org,
linux-renesas-soc@...r.kernel.org,
Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
Simon Horman <horms@...nel.org>
Subject: [PATCH net v3] ravb: Fix races between ravb_tx_timeout_work() and net related ops
Fix races between ravb_tx_timeout_work() and functions of net_device_ops
and ethtool_ops by using rtnl_trylock() and rtnl_unlock(). Note that
since ravb_close() is under the rtnl lock and calls cancel_work_sync(),
ravb_tx_timeout_work() should calls rtnl_trylock(). Otherwise, a deadlock
may happen in ravb_tx_timeout_work() like below:
CPU0 CPU1
ravb_tx_timeout()
schedule_work()
...
__dev_close_many()
// Under rtnl lock
ravb_close()
cancel_work_sync()
// Waiting
ravb_tx_timeout_work()
rtnl_lock()
// This is possible to cause a deadlock
And, if rtnl_trylock() fails and the netif is still running,
rescheduling the work with 1 msec delayed. So, using
schedule_delayed_work() instead of schedule_work().
Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@....ru>
Reviewed-by: Simon Horman <horms@...nel.org>
---
Changes from v2:
https://lore.kernel.org/netdev/20231019113308.1133944-1-yoshihiro.shimoda.uh@renesas.com/
- Add rescheduling if rtnl_trylock() fails and the netif is still running
and update commit description for it.
- Add Reviewed-by tags.
Changes from v1:
https://lore.kernel.org/all/20231017085341.813335-1-yoshihiro.shimoda.uh@renesas.com/
- Modify commit description.
- Use goto in a error path.
drivers/net/ethernet/renesas/ravb.h | 2 +-
drivers/net/ethernet/renesas/ravb_main.c | 20 +++++++++++++++-----
2 files changed, 16 insertions(+), 6 deletions(-)
diff --git a/drivers/net/ethernet/renesas/ravb.h b/drivers/net/ethernet/renesas/ravb.h
index e0f8276cffed..e9bb8ee3ba2d 100644
--- a/drivers/net/ethernet/renesas/ravb.h
+++ b/drivers/net/ethernet/renesas/ravb.h
@@ -1081,7 +1081,7 @@ struct ravb_private {
u32 cur_tx[NUM_TX_QUEUE];
u32 dirty_tx[NUM_TX_QUEUE];
struct napi_struct napi[NUM_RX_QUEUE];
- struct work_struct work;
+ struct delayed_work work;
/* MII transceiver section. */
struct mii_bus *mii_bus; /* MDIO bus control */
int link;
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index c70cff80cc99..ca7db8a5b412 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1863,17 +1863,24 @@ static void ravb_tx_timeout(struct net_device *ndev, unsigned int txqueue)
/* tx_errors count up */
ndev->stats.tx_errors++;
- schedule_work(&priv->work);
+ schedule_delayed_work(&priv->work, 0);
}
static void ravb_tx_timeout_work(struct work_struct *work)
{
- struct ravb_private *priv = container_of(work, struct ravb_private,
+ struct delayed_work *dwork = to_delayed_work(work);
+ struct ravb_private *priv = container_of(dwork, struct ravb_private,
work);
const struct ravb_hw_info *info = priv->info;
struct net_device *ndev = priv->ndev;
int error;
+ if (!rtnl_trylock()) {
+ if (netif_running(ndev))
+ schedule_delayed_work(&priv->work, msecs_to_jiffies(10));
+ return;
+ }
+
netif_tx_stop_all_queues(ndev);
/* Stop PTP Clock driver */
@@ -1907,7 +1914,7 @@ static void ravb_tx_timeout_work(struct work_struct *work)
*/
netdev_err(ndev, "%s: ravb_dmac_init() failed, error %d\n",
__func__, error);
- return;
+ goto out_unlock;
}
ravb_emac_init(ndev);
@@ -1917,6 +1924,9 @@ static void ravb_tx_timeout_work(struct work_struct *work)
ravb_ptp_init(ndev, priv->pdev);
netif_tx_start_all_queues(ndev);
+
+out_unlock:
+ rtnl_unlock();
}
/* Packet transmit function for Ethernet AVB */
@@ -2167,7 +2177,7 @@ static int ravb_close(struct net_device *ndev)
of_phy_deregister_fixed_link(np);
}
- cancel_work_sync(&priv->work);
+ cancel_delayed_work_sync(&priv->work);
if (info->multi_irqs) {
free_irq(priv->tx_irqs[RAVB_NC], ndev);
@@ -2687,7 +2697,7 @@ static int ravb_probe(struct platform_device *pdev)
ndev->base_addr = res->start;
spin_lock_init(&priv->lock);
- INIT_WORK(&priv->work, ravb_tx_timeout_work);
+ INIT_DELAYED_WORK(&priv->work, ravb_tx_timeout_work);
error = of_get_phy_mode(np, &priv->phy_interface);
if (error && error != -ENODEV)
--
2.25.1
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