Thought this would be of interest to the openSUSE community, since the e1000e bug caused a bit of a headache all around. The cause of the recent e1000e bug seems to be problems with ftrace code:

The cause of the bug is due to the way the current code in mainline
handles dynamic ftrace.  When dynamic ftrace is turned on, it also
turns on CONFIG_FTRACE which enables the -pg config in gcc that places
a call to mcount at every function call. With just CONFIG_FTRACE this
causes a noticeable overhead.  CONFIG_DYNAMIC_FTRACE works to ease this
overhead by dynamically updating the mcount call sites into nops.

The problem arises when we trace functions and modules are unloaded.
The first time a function is called, it will call mcount and the mcount
call will call ftrace_record_ip. This records the calling site and
stores it in a preallocated hash table. Later on a daemon will
wake up and call kstop_machine and convert any mcount callers into
nops.

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