Merge tag 'v4.4.291' into toradex_vf_4.4-nexttoradex_vf_4.4-nexttoradex_vf_4.4

This is the 4.4.291 stable release

Signed-off-by: Max Krummenacher <max.krummenacher@toradex.com>

1 files changed, 3 insertions, 7 deletions

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 6404e4fcb4ed..2f53786098c5 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1268,13 +1268,12 @@ out_unlock:
 }
 
 /*
- * FOLL_FORCE can write to even unwritable pmd's, but only
- * after we've gone through a COW cycle and they are dirty.
+ * FOLL_FORCE or a forced COW break can write even to unwritable pmd's,
+ * but only after we've gone through a COW cycle and they are dirty.
  */
 static inline bool can_follow_write_pmd(pmd_t pmd, unsigned int flags)
 {
-	return pmd_write(pmd) ||
-	       ((flags & FOLL_FORCE) && (flags & FOLL_COW) && pmd_dirty(pmd));
+	return pmd_write(pmd) || ((flags & FOLL_COW) && pmd_dirty(pmd));
 }
 
 struct page *follow_trans_huge_pmd(struct vm_area_struct *vma,
@@ -1341,9 +1340,6 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
 	bool was_writable;
 	int flags = 0;
 
-	/* A PROT_NONE fault should not end up here */
-	BUG_ON(!(vma->vm_flags & (VM_READ | VM_EXEC | VM_WRITE)));
-
 	ptl = pmd_lock(mm, pmdp);
 	if (unlikely(!pmd_same(pmd, *pmdp)))
 		goto out_unlock;