tree 105a72189d2783bfbca1ffda4f5ebf968ac69496
parent 1e2e99f0e4aa6363e8515ed17011c210c8f1b52a
author Loic Prylli <loic@myri.com> 1183714792 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1183742623 -0700

MTRR: Fix race causing set_mtrr to go into infinite loop

Processors synchronization in set_mtrr requires the .gate field to be set
after .count field is properly initialized.  Without an explicit barrier,
the compiler was reordering those memory stores.  That was sometimes
causing a processor (in ipi_handler) to see the .gate change and decrement
.count before the latter is set by set_mtrr() (which then hangs in a
infinite loop with irqs disabled).

Signed-off-by: Loic Prylli <loic@myri.com>
Cc: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>