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
Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
---
Changes from v1:
https://lore.kernel.org/all/20231017085341.813335-1-yoshihiro.shimoda.uh@xxxxxxxxxxx/
- Modify commit description.
- Use goto in a error path.
drivers/net/ethernet/renesas/ravb_main.c | 8 +++++++-
1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 0ef0b88b7145..300c1885e1e1 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -1874,6 +1874,9 @@ static void ravb_tx_timeout_work(struct work_struct *work)
struct net_device *ndev = priv->ndev;
int error;
+ if (!rtnl_trylock())
+ return;
+
netif_tx_stop_all_queues(ndev);
/* Stop PTP Clock driver */
@@ -1907,7 +1910,7 @@ 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 +1920,9 @@ 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 */
--
2.25.1
