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author | Adam Litke <agl@us.ibm.com> | 2005-09-03 15:55:00 -0700 |
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committer | Linus Torvalds <torvalds@evo.osdl.org> | 2005-09-05 00:05:46 -0700 |
commit | 7bf07f3d4b4358aa6d99a26d7a0165f1e91c3fcc (patch) | |
tree | 150e1f1172e3a7912b37bef7b06a657d47bc1657 /mm/hugetlb.c | |
parent | 32e51a8c976fc72c3e9bcece9767d9908816bf8e (diff) | |
download | linux-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/hugetlb.c')
-rw-r--r-- | mm/hugetlb.c | 2 |
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)); |