7beacad64edb8aa0cda
author Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1192602364 -0700
committer Linus Torvalds <torvalds@woody.linux-foundation.org> 1192635766 -0700

Immunize rcu_dereference() against crazy compiler writers

Turns out that compiler writers are a bit more aggressive about optimizing
than one might expect.  This patch prevents a number of such optimizations
from messing up rcu_deference().  This is not merely a theoretical problem, as
evidenced by the rmb() in mce_log().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Josh Triplett <josh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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