From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> stable inclusion from stable-5.10.68 commit 47bc9c3929eb0bafe805bf87474615c8596d16bc bugzilla: 182671 https://gitee.com/openeuler/kernel/issues/I4EWUH Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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: Chen Jun <chenjun102@huawei.com> Acked-by: Weilong Chen <chenweilong@huawei.com> Signed-off-by: Chen Jun <chenjun102@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 5cab2d3c0023..8927d5997745 100644 --- a/drivers/net/ethernet/renesas/sh_eth.c +++ b/drivers/net/ethernet/renesas/sh_eth.c @@ -2533,6 +2533,7 @@ static netdev_tx_t sh_eth_start_xmit(struct sk_buff *skb, 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)) -- 2.20.1