In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Fix SMP ordering in switch_mm_irqs_off()
Stephen noted that it is possible to not have an smp_mb() between
the loaded_mm store and the tlb_gen load in switch_mm(), meaning the
ordering against flush_tlb_mm_range() goes out the window, and it
becomes possible for switch_mm() to not observe a recent tlb_gen
update and fail to flush the TLBs.
[ dhansen: merge conflict fixed by Ingo ]
