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-rw-r--r--mm/shmem.c11
1 files changed, 11 insertions, 0 deletions
diff --git a/mm/shmem.c b/mm/shmem.c
index 99d5867daadb..16a3d7044c52 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -2274,6 +2274,16 @@ static int shmem_mfill_atomic_pte(struct mm_struct *dst_mm,
_dst_pte = mk_pte(page, dst_vma->vm_page_prot);
if (dst_vma->vm_flags & VM_WRITE)
_dst_pte = pte_mkwrite(pte_mkdirty(_dst_pte));
+ else {
+ /*
+ * We don't set the pte dirty if the vma has no
+ * VM_WRITE permission, so mark the page dirty or it
+ * could be freed from under us. We could do it
+ * unconditionally before unlock_page(), but doing it
+ * only if VM_WRITE is not set is faster.
+ */
+ set_page_dirty(page);
+ }
dst_pte = pte_offset_map_lock(dst_mm, dst_pmd, dst_addr, &ptl);
@@ -2307,6 +2317,7 @@ out:
return ret;
out_release_uncharge_unlock:
pte_unmap_unlock(dst_pte, ptl);
+ ClearPageDirty(page);
delete_from_page_cache(page);
out_release_uncharge:
mem_cgroup_cancel_charge(page, memcg, false);