Commit 72fad713 authored Dec 10, 2007 by Adam Litke Committed by Linus Torvalds Dec 10, 2007

hugetlb: handle write-protection faults in follow_hugetlb_page



The follow_hugetlb_page() fix I posted (merged as git commit
5b23dbe8) missed one case.  If the pte is
present, but not writable and write access is requested by the caller to
get_user_pages(), the code will do the wrong thing.  Rather than calling
hugetlb_fault to make the pte writable, it notes the presence of the pte
and continues.

This simple one-liner makes sure we also fault on the pte for this case.
Please apply.

Signed-off-by: Adam Litke <agl@us.ibm.com>
Acked-by: Dave Kleikamp <shaggy@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent 8805f238

mm/hugetlb.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -907,7 +907,7 @@ int follow_hugetlb_page(struct mm_struct mm, struct vm_area_struct vma,
		*/
		pte = huge_pte_offset(mm, vaddr & HPAGE_MASK);

		if (!pte \|\| pte_none(*pte)) {
		if (!pte \|\| pte_none(pte) \|\| (write && !pte_write(pte))) {
		int ret;

		spin_unlock(&mm->page_table_lock);