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: Sasha Levin alexander.levin@microsoft.com --- arch/sparc/mm/gup.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c index cd0e32bbcb1d..f80cfc64c55b 100644 --- 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_t pmd, unsigned long addr, 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;