[PATCH v1 1/5] mm: vmalloc must set pte via arch code

[Ryan Roberts]

It is bad practice to directly set pte entries within a pte table.
Instead all modifications must go through arch-provided helpers such as
set_pte_at() to give the arch code visibility and allow it to validate
(and potentially modify) the operation.

Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function")
Signed-off-by: Ryan Roberts <ryan.roberts@xxxxxxx>
---
 mm/vmalloc.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index 9683573f1225..d8d2fe797c55 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -2899,10 +2899,13 @@ struct vmap_pfn_data {
 static int vmap_pfn_apply(pte_t *pte, unsigned long addr, void *private)
 {
 	struct vmap_pfn_data *data = private;
+	pte_t ptent;
 
 	if (WARN_ON_ONCE(pfn_valid(data->pfns[data->idx])))
 		return -EINVAL;
-	*pte = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+
+	ptent = pte_mkspecial(pfn_pte(data->pfns[data->idx++], data->prot));
+	set_pte_at(&init_mm, addr, pte, ptent);
 	return 0;
 }
 
-- 
2.25.1