6.1-stable review patch. If anyone has any objections, please let me know.
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From: Claudiu Beznea claudiu.beznea.uj@bp.renesas.com
[ Upstream commit edf9bc396e05081ca281ffb0cd41e44db478ff26 ]
On RZ/G3S SMARC Carrier II board having RGMII connections b/w Ethernet MACs and PHYs it has been discovered that doing unbind/bind for ravb driver in a loop leads to wrong speed and duplex for Ethernet links and broken connectivity (the connectivity cannot be restored even with bringing interface down/up). Before doing unbind/bind the Ethernet interfaces were configured though systemd. The sh instructions used to do unbind/bind were:
$ cd /sys/bus/platform/drivers/ravb/ $ while :; do echo 11c30000.ethernet > unbind ; \ echo 11c30000.ethernet > bind; done
It has been discovered that there is a race b/w IOCTLs initialized by systemd at the response of success binding and the "ravb_write(ndev, CCC_OPC_RESET, CCC)" call in ravb_remove() as follows:
1/ as a result of bind success the user space open/configures the interfaces tough an IOCTL; the following stack trace has been identified on RZ/G3S:
Call trace: dump_backtrace+0x9c/0x100 show_stack+0x20/0x38 dump_stack_lvl+0x48/0x60 dump_stack+0x18/0x28 ravb_open+0x70/0xa58 __dev_open+0xf4/0x1e8 __dev_change_flags+0x198/0x218 dev_change_flags+0x2c/0x80 devinet_ioctl+0x640/0x708 inet_ioctl+0x1e4/0x200 sock_do_ioctl+0x50/0x108 sock_ioctl+0x240/0x358 __arm64_sys_ioctl+0xb0/0x100 invoke_syscall+0x50/0x128 el0_svc_common.constprop.0+0xc8/0xf0 do_el0_svc+0x24/0x38 el0_svc+0x34/0xb8 el0t_64_sync_handler+0xc0/0xc8 el0t_64_sync+0x190/0x198
2/ this call may execute concurrently with ravb_remove() as the unbind/bind operation was executed in a loop 3/ if the operation mode is changed to RESET (through ravb_write(ndev, CCC_OPC_RESET, CCC) call in ravb_remove()) while the above ravb_open() is in progress it may lead to MAC (or PHY, or MAC-PHY connection, the right point hasn't been identified at the moment) to be broken, thus the Ethernet connectivity fails to restore.
The simple fix for this is to move ravb_write(ndev, CCC_OPC_RESET, CCC)) after unregister_netdev() to avoid resetting the controller while the netdev interface is still registered.
To avoid future issues in ravb_remove(), the patch follows the proper order of operations in ravb_remove(): reverse order compared with ravb_probe(). This avoids described races as the IOCTLs as well as unregister_netdev() (called now at the beginning of ravb_remove()) calls rtnl_lock() before continuing and IOCTLs check (though devinet_ioctl()) if device is still registered just after taking the lock:
int devinet_ioctl(struct net *net, unsigned int cmd, struct ifreq *ifr) { // ...
rtnl_lock();
ret = -ENODEV; dev = __dev_get_by_name(net, ifr->ifr_name); if (!dev) goto done;
// ... done: rtnl_unlock(); out: return ret; }
Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper") Reviewed-by: Sergey Shtylyov s.shtylyov@omp.ru Signed-off-by: Claudiu Beznea claudiu.beznea.uj@bp.renesas.com Signed-off-by: Paolo Abeni pabeni@redhat.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/net/ethernet/renesas/ravb_main.c | 22 +++++++++++++--------- 1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c index e1c4a0ca4493f..68cb5616ef991 100644 --- a/drivers/net/ethernet/renesas/ravb_main.c +++ b/drivers/net/ethernet/renesas/ravb_main.c @@ -2919,22 +2919,26 @@ static int ravb_remove(struct platform_device *pdev) struct ravb_private *priv = netdev_priv(ndev); const struct ravb_hw_info *info = priv->info;
- /* Stop PTP Clock driver */ - if (info->ccc_gac) - ravb_ptp_stop(ndev); - - clk_disable_unprepare(priv->gptp_clk); - clk_disable_unprepare(priv->refclk); - - /* Set reset mode */ - ravb_write(ndev, CCC_OPC_RESET, CCC); unregister_netdev(ndev); if (info->nc_queues) netif_napi_del(&priv->napi[RAVB_NC]); netif_napi_del(&priv->napi[RAVB_BE]); + ravb_mdio_release(priv); + + /* Stop PTP Clock driver */ + if (info->ccc_gac) + ravb_ptp_stop(ndev); + dma_free_coherent(ndev->dev.parent, priv->desc_bat_size, priv->desc_bat, priv->desc_bat_dma); + + /* Set reset mode */ + ravb_write(ndev, CCC_OPC_RESET, CCC); + + clk_disable_unprepare(priv->gptp_clk); + clk_disable_unprepare(priv->refclk); + pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); reset_control_assert(priv->rstc);