4.19-stable review patch. If anyone has any objections, please let me know. ------------------ From: Shenwei Wang <shenwei.wang@xxxxxxx> [ Upstream commit 5e344807735023cd3a67c37a1852b849caa42620 ] When repeatedly changing the interface link speed using the command below: ethtool -s eth0 speed 100 duplex full ethtool -s eth0 speed 1000 duplex full The following errors may sometimes be reported by the ARM SMMU driver: [ 5395.035364] fec 5b040000.ethernet eth0: Link is Down [ 5395.039255] arm-smmu 51400000.iommu: Unhandled context fault: fsr=0x402, iova=0x00000000, fsynr=0x100001, cbfrsynra=0x852, cb=2 [ 5398.108460] fec 5b040000.ethernet eth0: Link is Up - 100Mbps/Full - flow control off It is identified that the FEC driver does not properly stop the TX queue during the link speed transitions, and this results in the invalid virtual I/O address translations from the SMMU and causes the context faults. Fixes: dbc64a8ea231 ("net: fec: move calls to quiesce/resume packet processing out of fec_restart()") Signed-off-by: Shenwei Wang <shenwei.wang@xxxxxxx> Link: https://lore.kernel.org/r/20240123165141.2008104-1-shenwei.wang@xxxxxxx Signed-off-by: Paolo Abeni <pabeni@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> --- drivers/net/ethernet/freescale/fec_main.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/net/ethernet/freescale/fec_main.c +++ b/drivers/net/ethernet/freescale/fec_main.c @@ -1798,6 +1798,7 @@ static void fec_enet_adjust_link(struct /* if any of the above changed restart the FEC */ if (status_change) { + netif_stop_queue(ndev); napi_disable(&fep->napi); netif_tx_lock_bh(ndev); fec_restart(ndev); @@ -1807,6 +1808,7 @@ static void fec_enet_adjust_link(struct } } else { if (fep->link) { + netif_stop_queue(ndev); napi_disable(&fep->napi); netif_tx_lock_bh(ndev); fec_stop(ndev);