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authorHillf Danton <dhillf@gmail.com>2012-01-20 14:34:13 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2012-01-23 08:38:48 -0800
commit409eb8c2611b4310947a150af988111f7f52ab15 (patch)
treea410c7c9c5a58643da7b4c2abdb7796d1255f048 /mm
parent6568d4a9c9ff16d6c4f0b14dfea567806ce579e4 (diff)
downloadlinux-409eb8c2611b4310947a150af988111f7f52ab15.tar.gz
mm/hugetlb.c: undo change to page mapcount in fault handler
Page mapcount should be updated only if we are sure that the page ends up in the page table otherwise we would leak if we couldn't COW due to reservations or if idx is out of bounds. Signed-off-by: Hillf Danton <dhillf@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> 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/hugetlb.c9
1 files changed, 6 insertions, 3 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index ea8c3a4cd2a..5f34bd8dda3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -2508,6 +2508,7 @@ static int hugetlb_no_page(struct mm_struct *mm, struct vm_area_struct *vma,
{
struct hstate *h = hstate_vma(vma);
int ret = VM_FAULT_SIGBUS;
+ int anon_rmap = 0;
pgoff_t idx;
unsigned long size;
struct page *page;
@@ -2562,14 +2563,13 @@ retry:
spin_lock(&inode->i_lock);
inode->i_blocks += blocks_per_huge_page(h);
spin_unlock(&inode->i_lock);
- page_dup_rmap(page);
} else {
lock_page(page);
if (unlikely(anon_vma_prepare(vma))) {
ret = VM_FAULT_OOM;
goto backout_unlocked;
}
- hugepage_add_new_anon_rmap(page, vma, address);
+ anon_rmap = 1;
}
} else {
/*
@@ -2582,7 +2582,6 @@ retry:
VM_FAULT_SET_HINDEX(h - hstates);
goto backout_unlocked;
}
- page_dup_rmap(page);
}
/*
@@ -2606,6 +2605,10 @@ retry:
if (!huge_pte_none(huge_ptep_get(ptep)))
goto backout;
+ if (anon_rmap)
+ hugepage_add_new_anon_rmap(page, vma, address);
+ else
+ page_dup_rmap(page);
new_pte = make_huge_pte(vma, page, ((vma->vm_flags & VM_WRITE)
&& (vma->vm_flags & VM_SHARED)));
set_huge_pte_at(mm, address, ptep, new_pte);