From: Carsten Otte <cotte@de.ibm.com>
Date: Sun, 30 Oct 2011 14:17:02 +0000 (+0100)
Subject: [S390] take mmap_sem when walking guest page table
X-Git-Tag: v3.2-rc1~109^2~19
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=499069e1a421e2a85e76846c3237f00f1a5cb435;p=pandora-kernel.git

[S390] take mmap_sem when walking guest page table

gmap_fault needs to walk the guest page table. However, parts of
that may change if some other thread does munmap. In that case
gmap_unmap_notifier will also unmap the corresponding parts from
the guest page table. We need to take mmap_sem in order to serialize
these operations.
do_exception now calls __gmap_fault with mmap_sem held which does
not get exported to modules. The exported function, which is called
from KVM, now takes mmap_sem.

Reported-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Carsten Otte <cotte@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
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