| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.12 23/84] sparc64: Fix gup_huge_pmd | Date | Wed, 19 Jul 2017 11:43:29 +0200 |
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4.12-stable review patch. If anyone has any objections, please let me know.
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From: Nitin Gupta <nitin.m.gupta@oracle.com>
[ Upstream commit dbd2667a4fb9ce4f547982b07cd69dda127c47ea ]
The function assumes that each PMD points to head of a huge page. This is not correct as a PMD can point to start of any 8M region with a, say 256M, hugepage. The fix ensures that it points to the correct head of any PMD huge page.
Cc: Julian Calaby <julian.calaby@gmail.com> Signed-off-by: Nitin Gupta <nitin.m.gupta@oracle.com> Signed-off-by: David S. Miller <davem@davemloft.net> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- arch/sparc/mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
--- a/arch/sparc/mm/gup.c +++ b/arch/sparc/mm/gup.c @@ -78,8 +78,8 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd return 0; refs = 0; - head = pmd_page(pmd); - page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT); + page = pmd_page(pmd) + ((addr & ~PMD_MASK) >> PAGE_SHIFT); + head = compound_head(page); do { VM_BUG_ON(compound_head(page) != head); pages[*nr] = page;
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