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.
Signed-off-by: Nitin Gupta <nitin.m.gupta@xxxxxxxxxx>
---
arch/sparc/mm/gup.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/sparc/mm/gup.c b/arch/sparc/mm/gup.c
index cd0e32b..9116a6f 100644
--- a/arch/sparc/mm/gup.c
+++ b/arch/sparc/mm/gup.c
@@ -80,6 +80,8 @@ static int gup_huge_pmd(pmd_t *pmdp, pmd_t pmd, unsigned long addr,
refs = 0;
head = pmd_page(pmd);
page = head + ((addr & ~PMD_MASK) >> PAGE_SHIFT);
+ if (PageTail(head))
+ head = compound_head(head);
do {
VM_BUG_ON(compound_head(page) != head);
pages[*nr] = page;
--
2.9.2
--
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