Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935719AbdCJNoC (ORCPT ); Fri, 10 Mar 2017 08:44:02 -0500 Received: from shadbolt.e.decadent.org.uk ([88.96.1.126]:42850 "EHLO shadbolt.e.decadent.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S934300AbdCJLwY (ORCPT ); Fri, 10 Mar 2017 06:52:24 -0500 Content-Type: text/plain; charset="UTF-8" Content-Disposition: inline Content-Transfer-Encoding: 8bit MIME-Version: 1.0 From: Ben Hutchings To: linux-kernel@vger.kernel.org, stable@vger.kernel.org CC: akpm@linux-foundation.org, "David S. Miller" , "Kweh, Hock Leong" , "Florian Fainelli" Date: Fri, 10 Mar 2017 11:46:22 +0000 Message-ID: X-Mailer: LinuxStableQueue (scripts by bwh) Subject: [PATCH 3.16 128/370] net: stmmac: Fix race between stmmac_drv_probe and stmmac_open In-Reply-To: X-SA-Exim-Connect-IP: 82.70.136.246 X-SA-Exim-Mail-From: ben@decadent.org.uk X-SA-Exim-Scanned: No (on shadbolt.decadent.org.uk); SAEximRunCond expanded to false Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3417 Lines: 84 3.16.42-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: Florian Fainelli commit 5701659004d68085182d2fd4199c79172165fa65 upstream. There is currently a small window during which the network device registered by stmmac can be made visible, yet all resources, including and clock and MDIO bus have not had a chance to be set up, this can lead to the following error to occur: [ 473.919358] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): stmmac_dvr_probe: warning: cannot get CSR clock [ 473.919382] stmmaceth 0000:01:00.0: no reset control found [ 473.919412] stmmac - user ID: 0x10, Synopsys ID: 0x42 [ 473.919429] stmmaceth 0000:01:00.0: DMA HW capability register supported [ 473.919436] stmmaceth 0000:01:00.0: RX Checksum Offload Engine supported [ 473.919443] stmmaceth 0000:01:00.0: TX Checksum insertion supported [ 473.919451] stmmaceth 0000:01:00.0 (unnamed net_device) (uninitialized): Enable RX Mitigation via HW Watchdog Timer [ 473.921395] libphy: PHY stmmac-1:00 not found [ 473.921417] stmmaceth 0000:01:00.0 eth0: Could not attach to PHY [ 473.921427] stmmaceth 0000:01:00.0 eth0: stmmac_open: Cannot attach to PHY (error: -19) [ 473.959710] libphy: stmmac: probed [ 473.959724] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 0 IRQ POLL (stmmac-1:00) active [ 473.959728] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 1 IRQ POLL (stmmac-1:01) [ 473.959731] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 2 IRQ POLL (stmmac-1:02) [ 473.959734] stmmaceth 0000:01:00.0 eth0: PHY ID 01410cc2 at 3 IRQ POLL (stmmac-1:03) Fix this by making sure that register_netdev() is the last thing being done, which guarantees that the clock and the MDIO bus are available. Fixes: 4bfcbd7abce2 ("stmmac: Move the mdio_register/_unregister in probe/remove") Reported-by: Kweh, Hock Leong Signed-off-by: Florian Fainelli Signed-off-by: David S. Miller [bwh: Backported to 3.16: - stmmac_dvr_probe() returns a pointer - Adjust context] Signed-off-by: Ben Hutchings --- drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c @@ -2769,12 +2769,6 @@ struct stmmac_priv *stmmac_dvr_probe(str spin_lock_init(&priv->lock); spin_lock_init(&priv->tx_lock); - ret = register_netdev(ndev); - if (ret) { - pr_err("%s: ERROR %i registering the device\n", __func__, ret); - goto error_netdev_register; - } - /* If a specific clk_csr value is passed from the platform * this means that the CSR Clock Range selection cannot be * changed at run-time and it is fixed. Viceversa the driver'll try to @@ -2799,11 +2793,14 @@ struct stmmac_priv *stmmac_dvr_probe(str } } - return priv; + ret = register_netdev(ndev); + if (ret) + netdev_err(priv->dev, "%s: ERROR %i registering the device\n", + __func__, ret); + + return ret ? ERR_PTR(ret) : priv; error_mdio_register: - unregister_netdev(ndev); -error_netdev_register: netif_napi_del(&priv->napi); error_hw_init: clk_disable_unprepare(priv->stmmac_clk);