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authorOleg Nesterov <oleg@redhat.com>2013-07-31 13:53:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2013-07-31 14:41:02 -0700
commit3964acd0dbec123aa0a621973a2a0580034b4788 (patch)
treeeb5bcfb186354c2ebfa6b0b07c37156b34d21e9e /mm
parent36f571e9ed0419e73d127e18aa8992ced867268c (diff)
downloadop-kernel-dev-3964acd0dbec123aa0a621973a2a0580034b4788.zip
op-kernel-dev-3964acd0dbec123aa0a621973a2a0580034b4788.tar.gz
mm: mempolicy: fix mbind_range() && vma_adjust() interaction
vma_adjust() does vma_set_policy(vma, vma_policy(next)) and this is doubly wrong: 1. This leaks vma->vm_policy if it is not NULL and not equal to next->vm_policy. This can happen if vma_merge() expands "area", not prev (case 8). 2. This sets the wrong policy if vma_merge() joins prev and area, area is the vma the caller needs to update and it still has the old policy. Revert commit 1444f92c8498 ("mm: merging memory blocks resets mempolicy") which introduced these problems. Change mbind_range() to recheck mpol_equal() after vma_merge() to fix the problem that commit tried to address. Signed-off-by: Oleg Nesterov <oleg@redhat.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Steven T Hampson <steven.t.hampson@intel.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/mempolicy.c6
-rw-r--r--mm/mmap.c2
2 files changed, 6 insertions, 2 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index 7431001..4baf12e 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -732,7 +732,10 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
if (prev) {
vma = prev;
next = vma->vm_next;
- continue;
+ if (mpol_equal(vma_policy(vma), new_pol))
+ continue;
+ /* vma_merge() joined vma && vma->next, case 8 */
+ goto replace;
}
if (vma->vm_start != vmstart) {
err = split_vma(vma->vm_mm, vma, vmstart, 1);
@@ -744,6 +747,7 @@ static int mbind_range(struct mm_struct *mm, unsigned long start,
if (err)
goto out;
}
+ replace:
err = vma_replace_policy(vma, new_pol);
if (err)
goto out;
diff --git a/mm/mmap.c b/mm/mmap.c
index fbad7b0..1edbaa3 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -865,7 +865,7 @@ again: remove_next = 1 + (end > next->vm_end);
if (next->anon_vma)
anon_vma_merge(vma, next);
mm->map_count--;
- vma_set_policy(vma, vma_policy(next));
+ mpol_put(vma_policy(next));
kmem_cache_free(vm_area_cachep, next);
/*
* In mprotect's case 6 (see comments on vma_merge),
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