From: Loic Prylli <loic@myri.com>
Date: Fri, 6 Jul 2007 09:39:52 +0000 (-0700)
Subject: MTRR: Fix race causing set_mtrr to go into infinite loop
X-Git-Tag: v2.6.22~19
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d25c1ba2fa1a9a1a4f68bef8edb0efefd79f0012;p=pandora-kernel.git

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>
---

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