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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Zhang Run <zhang.run@zte.com.cn>,
        Yang Wei <yang.wei9@zte.com.cn>,
        Marcel Ziswiler <marcel.ziswiler@toradex.com>,
        "David S. Miller" <davem@davemloft.net>,
        Sasha Levin <sashal@kernel.org>
Subject: [PATCH 4.20 58/88] net: usb: asix: ax88772_bind return error when hw_reset fail
Date:   Mon,  4 Mar 2019 09:22:41 +0100
Message-Id: <20190304081632.832064964@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit 6eea3527e68acc22483f4763c8682f223eb90029 ]

The ax88772_bind() should return error code immediately when the PHY
was not reset properly through ax88772a_hw_reset().
Otherwise, The asix_get_phyid() will block when get the PHY
Identifier from the PHYSID1 MII registers through asix_mdio_read()
due to the PHY isn't ready. Furthermore, it will produce a lot of
error message cause system crash.As follows:
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to write
 reg index 0x0000: -71
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to send
 software reset: ffffffb9
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to write
 reg index 0x0000: -71
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to enable
 software MII access
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to read
 reg index 0x0000: -71
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to write
 reg index 0x0000: -71
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to enable
 software MII access
asix 1-1:1.0 (unnamed net_device) (uninitialized): Failed to read
 reg index 0x0000: -71
...

Signed-off-by: Zhang Run <zhang.run@zte.com.cn>
Reviewed-by: Yang Wei <yang.wei9@zte.com.cn>
Tested-by: Marcel Ziswiler <marcel.ziswiler@toradex.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/net/usb/asix_devices.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/asix_devices.c b/drivers/net/usb/asix_devices.c
index b654f05b2ccd0..3d93993e74da0 100644
--- a/drivers/net/usb/asix_devices.c
+++ b/drivers/net/usb/asix_devices.c
@@ -739,8 +739,13 @@ static int ax88772_bind(struct usbnet *dev, struct usb_interface *intf)
 	asix_read_cmd(dev, AX_CMD_STATMNGSTS_REG, 0, 0, 1, &chipcode, 0);
 	chipcode &= AX_CHIPCODE_MASK;
 
-	(chipcode == AX_AX88772_CHIPCODE) ? ax88772_hw_reset(dev, 0) :
-					    ax88772a_hw_reset(dev, 0);
+	ret = (chipcode == AX_AX88772_CHIPCODE) ? ax88772_hw_reset(dev, 0) :
+						  ax88772a_hw_reset(dev, 0);
+
+	if (ret < 0) {
+		netdev_dbg(dev->net, "Failed to reset AX88772: %d\n", ret);
+		return ret;
+	}
 
 	/* Read PHYID register *AFTER* the PHY was reset properly */
 	phyid = asix_get_phyid(dev);
-- 
2.19.1