The x86-64 kernel incorrectly marks the 32-bit vsyscall page mapping at
virtual address 0xffffe000 as a global one, even though that mapping
does not exist globally.  As such, task switches do not correctly
invalidate the mapping, and strange behaviour ensues if a 64-bit program
happens to use that same virtual address for something else.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>