Bingo! With the above patch:and this is also part of the DEBUG_PAGEALLOC + trinity combo! I suspect
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>[ 243.565794] kernel BUG at mm/vmacache.c:76!
>[ 243.566720] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
>[ 243.568048] Dumping ftrace buffer:
>[ 243.568740] (ftrace buffer empty)
>[ 243.569481] Modules linked in:
>[ 243.570203] CPU: 10 PID: 10073 Comm: trinity-c332 Tainted: G W 3.14.0-rc5-next-20140307-sasha-00010-g1f812cb-dirty #143
the root cause it the same as Fengguang's report.