tree 053272b5cf133ddfdff5167a8b951b1c1c5cdb90
parent bbef56d861f103058e387ad5354b4083b9892a7c
author Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> 1631014180 +0900
committer David S. Miller <davem@davemloft.net> 1631019722 +0100

net: renesas: sh_eth: Fix freeing wrong tx descriptor

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>