* missing check in __get_user_pages
@ 2014-06-10 14:54 Dave Jones
2014-06-10 15:34 ` Kirill A. Shutemov
0 siblings, 1 reply; 2+ messages in thread
From: Dave Jones @ 2014-06-10 14:54 UTC (permalink / raw)
To: linux-mm
coverity flagged this code in __get_user_pages
448 if (is_vm_hugetlb_page(vma)) {
449 i = follow_hugetlb_page(mm, vma, pages, vmas,
450 &start, &nr_pages, i,
451 gup_flags);
452 continue;
453 }
It seems unaware that follow_hugetlb_page can in some cases return -EFAULT.
I'm not sure if this is triggerable, but it looks dangerous.
Dave
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* Re: missing check in __get_user_pages
2014-06-10 14:54 missing check in __get_user_pages Dave Jones
@ 2014-06-10 15:34 ` Kirill A. Shutemov
0 siblings, 0 replies; 2+ messages in thread
From: Kirill A. Shutemov @ 2014-06-10 15:34 UTC (permalink / raw)
To: Dave Jones; +Cc: linux-mm
On Tue, Jun 10, 2014 at 10:54:39AM -0400, Dave Jones wrote:
> coverity flagged this code in __get_user_pages
>
> 448 if (is_vm_hugetlb_page(vma)) {
> 449 i = follow_hugetlb_page(mm, vma, pages, vmas,
> 450 &start, &nr_pages, i,
> 451 gup_flags);
> 452 continue;
> 453 }
>
> It seems unaware that follow_hugetlb_page can in some cases return -EFAULT.
> I'm not sure if this is triggerable, but it looks dangerous.
Looks like follow_hugetlb_page() sets nr_pages to 0 in this case, and
__get_user_pages() can handle this correctly.
But, yes, it's ugly.
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Kirill A. Shutemov
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2014-06-10 15:34 ` Kirill A. Shutemov
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