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-rw-r--r--mm/ksm.c10
1 files changed, 8 insertions, 2 deletions
diff --git a/mm/ksm.c b/mm/ksm.c
index c2013f638d11..b99e828172f6 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -359,6 +359,10 @@ static inline bool ksm_test_exit(struct mm_struct *mm)
* in case the application has unmapped and remapped mm,addr meanwhile.
* Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP
* mmap of /dev/mem or /dev/kmem, where we would not want to touch it.
+ *
+ * FAULT_FLAG/FOLL_REMOTE are because we do this outside the context
+ * of the process that owns 'vma'. We also do not want to enforce
+ * protection keys here anyway.
*/
static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
{
@@ -367,12 +371,14 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
do {
cond_resched();
- page = follow_page(vma, addr, FOLL_GET | FOLL_MIGRATION);
+ page = follow_page(vma, addr,
+ FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE);
if (IS_ERR_OR_NULL(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma->vm_mm, vma, addr,
- FAULT_FLAG_WRITE);
+ FAULT_FLAG_WRITE |
+ FAULT_FLAG_REMOTE);
else
ret = VM_FAULT_WRITE;
put_page(page);