From cd2567b6850b1648236a4aab0513a04ebaea6aa8 Mon Sep 17 00:00:00 2001
From: Davidlohr Bueso <davidlohr@hp.com>
Date: Thu, 9 Oct 2014 15:29:45 -0700
Subject: [PATCH] m68k: call find_vma with the mmap_sem held in
 sys_cacheflush()

Performing vma lookups without taking the mm->mmap_sem is asking for
trouble.  While doing the search, the vma in question can be modified or
even removed before returning to the caller.  Take the lock (shared) in
order to avoid races while iterating through the vmacache and/or rbtree.
In addition, this guarantees that the address space will remain intact
during the CPU flushing.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---
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