From: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com
stable inclusion from linux-4.19.207 commit 044e7097e849366dfc71cccfc5d8c8a97cb3f010
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[ Upstream commit 0341d5e3d1ee2a36dd5a49b5bef2ce4ad1cfa6b4 ]
The cur_tx counter must be incremented after TACT bit of txdesc->status was set. However, a CPU is possible to reorder instructions and/or memory accesses between cur_tx and txdesc->status. And then, if TX interrupt happened at such a timing, the sh_eth_tx_free() may free the descriptor wrongly. So, add wmb() before cur_tx++. Otherwise NETDEV WATCHDOG timeout is possible to happen.
Fixes: 86a74ff21a7a ("net: sh_eth: add support for Renesas SuperH Ethernet") Signed-off-by: Yoshihiro Shimoda yoshihiro.shimoda.uh@renesas.com Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/net/ethernet/renesas/sh_eth.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c index 394ab9cdfe2c7..c44aea47c1208 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -2547,6 +2547,7 @@ static int sh_eth_start_xmit(struct sk_buff *skb, struct net_device *ndev) else txdesc->status |= cpu_to_le32(TD_TACT);
+ wmb(); /* cur_tx must be incremented after TACT bit was set */ mdp->cur_tx++;
if (!(sh_eth_read(ndev, EDTRR) & mdp->cd->edtrr_trns))