Loading kernel and initrd via ipxe causes it to crash during startup, the 32bit
kernel works fine, though.

Output captured from qemu :

[    3.122744] CPU: 0 PID: 1 Comm: swapper/0 Not tainted
3.17.1-1.g5c4d099-default #1     
[    3.122829] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
1.7.5-20140531_083030-gandalf 04/01/2014
[    3.123020]  ffff88001f767e60 ffffffff815daea6 ffffffff81809668
ffffffff815d6048
[    3.123200]  ffffffff00000010 ffff88001f767e70 ffff88001f767e10
ffffffff815d67cb                                                           
[    3.123316]  ffff88001f767e78 0000000000000000 ffff88001e50beb0
0000000000000000
[    3.123456] Call Trace:                                              
[    3.124278]  [<ffffffff81005096>] dump_trace+0x86/0x330  
[    3.124278]  [<ffffffff810053d4>] show_stack_log_lvl+0x94/0x170
[    3.124278]  [<ffffffff81006a31>] show_stack+0x21/0x50
[    3.124278]  [<ffffffff815daea6>] dump_stack+0x41/0x51
[    3.124278]  [<ffffffff815d6048>] panic+0xc8/0x1fc
[    3.124278]  [<ffffffff81d0f537>] mount_block_root+0x22b/0x2b8
[    3.124278]  [<ffffffff81d0f747>] prepare_namespace+0x133/0x169
[    3.124278]  [<ffffffff81d0f263>] kernel_init_freeable+0x1f5/0x202           
[    3.124278]  [<ffffffff815ccf8a>] kernel_init+0xa/0xf0
[    3.124278]  [<ffffffff815e14fc>] ret_from_fork+0x7c/0xb0         
[    3.124278] Kernel Offset: 0x0 from 0xffffffff81000000 (relocation range:
0xffffffff80000000-0xffffffff9fffffff)
[    3.124278] Rebooting in 90 seconds..