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authorAdam Litke <agl@us.ibm.com>2005-09-03 15:55:00 -0700
committerLinus Torvalds <torvalds@evo.osdl.org>2005-09-05 00:05:46 -0700
commit7bf07f3d4b4358aa6d99a26d7a0165f1e91c3fcc (patch)
tree150e1f1172e3a7912b37bef7b06a657d47bc1657 /mm
parent32e51a8c976fc72c3e9bcece9767d9908816bf8e (diff)
downloadlinux-sh-7bf07f3d4b4358aa6d99a26d7a0165f1e91c3fcc.tar.gz
[PATCH] hugetlb: move stale pte check into huge_pte_alloc()
Initial Post (Wed, 17 Aug 2005) This patch moves the if (! pte_none(*pte)) hugetlb_clean_stale_pgtable(pte); logic into huge_pte_alloc() so all of its callers can be immune to the bug described by Kenneth Chen at http://lkml.org/lkml/2004/6/16/246 > It turns out there is a bug in hugetlb_prefault(): with 3 level page table, > huge_pte_alloc() might return a pmd that points to a PTE page. It happens > if the virtual address for hugetlb mmap is recycled from previously used > normal page mmap. free_pgtables() might not scrub the pmd entry on > munmap and hugetlb_prefault skips on any pmd presence regardless what type > it is. Unless I am missing something, it seems more correct to place the check inside huge_pte_alloc() to prevent a the same bug wherever a huge pte is allocated. It also allows checking for this condition when lazily faulting huge pages later in the series. Signed-off-by: Adam Litke <agl@us.ibm.com> Cc: <linux-mm@kvack.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'mm')
-rw-r--r--mm/hugetlb.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index 6bf720bc662c..901ac523a1c3 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -360,8 +360,6 @@ int hugetlb_prefault(struct address_space *mapping, struct vm_area_struct *vma)
ret = -ENOMEM;
goto out;
}
- if (! pte_none(*pte))
- hugetlb_clean_stale_pgtable(pte);
idx = ((addr - vma->vm_start) >> HPAGE_SHIFT)
+ (vma->vm_pgoff >> (HPAGE_SHIFT - PAGE_SHIFT));