[PATCH 3.14 17/23] net/at91_ether: avoid NULL pointer dereference

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

3.14-stable review patch.  If anyone has any objections, please let me know.

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

From: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>

[ Upstream commit c293fb785bdda64d88f197e6758a3c16ae83e569 ]

The at91_ether driver calls macb_mii_init passing a 'struct macb'
structure whose tx_clk member is initialized to 0. However,
macb_handle_link_change() expects tx_clk to be the result of
a call to clk_get, and so IS_ERR(tx_clk) to be true if the clock
is invalid. This causes an oops when booting Linux 3.14 on the
csb637 board. The following changes avoids this.

Signed-off-by: Gilles Chanteperdrix <gilles.chanteperdrix@xenomai.org>
Acked-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/cadence/at91_ether.c |    3 +++
 1 file changed, 3 insertions(+)

--- a/drivers/net/ethernet/cadence/at91_ether.c
+++ b/drivers/net/ethernet/cadence/at91_ether.c
@@ -342,6 +342,9 @@ static int __init at91ether_probe(struct
 	}
 	clk_enable(lp->pclk);
 
+	lp->hclk = ERR_PTR(-ENOENT);
+	lp->tx_clk = ERR_PTR(-ENOENT);
+
 	/* Install the interrupt handler */
 	dev->irq = platform_get_irq(pdev, 0);
 	res = devm_request_irq(&pdev->dev, dev->irq, at91ether_interrupt, 0, dev->name, dev);