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Date: Thu, 17 Dec 2015 15:52:39 -0800
From: Calvin Owens <calvinowens@fb.com>
To: <davem@davemloft.net>, <shm@cumulusnetworks.com>,
        <izumi.taku@jp.fujitsu.com>, <linville@tuxdriver.com>,
        <dsa@cumulusnetworks.com>
CC: <netdev@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
        <kernel-team@fb.com>, <calvinowens@fb.com>
Subject: [PATCH] netconsole: Initialize after all core networking drivers
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With built-in netconsole and IXGBE, configuring netconsole via the kernel
cmdline results in the following panic at boot:

    netpoll: netconsole: device eth0 not up yet, forcing it
    usb 2-1: new high-speed USB device number 2 using ehci-pci
    ixgbe 0000:03:00.0: registered PHC device on eth0
    BUG: unable to handle kernel NULL pointer dereference at 0000000000000810
    <snip>
    Call Trace:
     [<ffffffff81578661>] ? vxlan_get_rx_port+0x41/0xa0
     [<ffffffff81586828>] ixgbe_open+0x4e8/0x540
     [<ffffffff8168045c>] __dev_open+0xac/0x120
     [<ffffffff81680506>] dev_open+0x36/0x70
     [<ffffffff8169abec>] netpoll_setup+0x23c/0x300
     [<ffffffff8169a66a>] ? netpoll_parse_options+0x19a/0x200
     [<ffffffff81d797a8>] ? option_setup+0x1f/0x1f
     [<ffffffff81d79882>] init_netconsole+0xda/0x262
     [<ffffffff81d797a8>] ? option_setup+0x1f/0x1f
     [<ffffffff810003a8>] do_one_initcall+0x88/0x1b0
     [<ffffffff81d31144>] kernel_init_freeable+0x14a/0x1e3
     [<ffffffff81d308f1>] ? do_early_param+0x8c/0x8c
     [<ffffffff81778610>] ? rest_init+0x80/0x80
     [<ffffffff8177861e>] kernel_init+0xe/0xe0
     [<ffffffff8177dc5f>] ret_from_fork+0x3f/0x70
     [<ffffffff81778610>] ? rest_init+0x80/0x80

This happens because IXGBE assumes that vxlan has already been initialized.
The cleanest way to fix this is to just initialize netconsole after all the
other core networking stuff has completed.

Signed-off-by: Calvin Owens <calvinowens@fb.com>
---
 drivers/net/Makefile | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 900b0c5..31557d0 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -15,7 +15,6 @@ obj-$(CONFIG_MACVTAP) += macvtap.o
 obj-$(CONFIG_MII) += mii.o
 obj-$(CONFIG_MDIO) += mdio.o
 obj-$(CONFIG_NET) += Space.o loopback.o
-obj-$(CONFIG_NETCONSOLE) += netconsole.o
 obj-$(CONFIG_PHYLIB) += phy/
 obj-$(CONFIG_RIONET) += rionet.o
 obj-$(CONFIG_NET_TEAM) += team/
@@ -26,6 +25,7 @@ obj-$(CONFIG_VXLAN) += vxlan.o
 obj-$(CONFIG_GENEVE) += geneve.o
 obj-$(CONFIG_NLMON) += nlmon.o
 obj-$(CONFIG_NET_VRF) += vrf.o
+obj-$(CONFIG_NETCONSOLE) += netconsole.o
 
 #
 # Networking Drivers
-- 
2.5.0

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