My kernel configuration had CONFIG_PREEMPT=y, and the ixgbe 3.0.12 module produced the following error message when it was loaded.
BUG: using smp_processor_id() in preemptible  code:
Kernel config file attached (config-WR3.0.2ax_cgl)
Hardware config of the target attached with lspci -vvv & dmidecode output (hwcfg.txt)
Attached is a patch that works for me to resolve this (ixgbe-preempt.patch). Please review it.