net/macb: check if macb_config present
authorAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Fri, 24 Jul 2015 18:24:00 +0000 (21:24 +0300)
committerDavid S. Miller <davem@davemloft.net>
Mon, 27 Jul 2015 08:10:29 +0000 (01:10 -0700)
commitf36dbe6a285e0628e67b7bd9d3b08599184d7d2c
tree66a2219a606830a09e690de8ae5741572e083255
parentf2ce8a9e48385f444389e75cfe293637c3eb5410
net/macb: check if macb_config present

The commit 98b5a0f4a228 introduces jumbo frame support, but also it assumes
that macb_config present which is not always true.

The configuration without macb_config fails to boot.

 Unable to handle kernel NULL pointer dereference at virtual address 00000010
 ptbr = 90350000 pgd = 00000000
 Oops: Kernel access of bad area, sig: 11 [#1]
 FRAME_POINTER chip: 0x01f:0x1e82 rev 2
 Modules linked in:
 CPU: 0 PID: 1 Comm: swapper Not tainted 4.2.0-rc3-next-20150723+ #13
 task: 91c26000 ti: 91c28000 task.ti: 91c28000
 PC is at macb_probe+0x140/0x61c

Fixes: 98b5a0f4a228 (net: macb: Add support for jumbo frames)
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/cadence/macb.c