4.14-stable review patch. If anyone has any objections, please let me know.
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From: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com
[ Upstream commit 9870257a0a338cd8d6c1cddab74e703f490f6779 ]
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
If rtnl_trylock() fails, rescheduling the work with sleep for 1 msec.
Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper") Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Reviewed-by: Sergey Shtylyov s.shtylyov@omp.ru Link: https://lore.kernel.org/r/20231127122420.3706751-1-yoshihiro.shimoda.uh@rene... Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/renesas/ravb_main.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index 4acea1ab60008..4db3495ef3370 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -1484,6 +1484,12 @@ static void ravb_tx_timeout_work(struct work_struct *work) struct net_device *ndev = priv->ndev; int error;
+ if (!rtnl_trylock()) { + usleep_range(1000, 2000); + schedule_work(&priv->work); + return; + } + netif_tx_stop_all_queues(ndev);
/* Stop PTP Clock driver */ @@ -1516,7 +1522,7 @@ 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);
@@ -1526,6 +1532,9 @@ 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 */