[PATCH 2/2] mm/vmalloc: warn on NULL page in remap_vmalloc_range_partial

[Ye Liu <ye.liu@linux.dev>]

From: Ye Liu <liuye@kylinos.cn>

remap_vmalloc_range_partial() oopses if vmalloc_to_page() returns
NULL, which never happens today because VM_USERMAP areas keep every
page mapped. Add a WARN_ON(!page) to flag a break before the oops.

Signed-off-by: Ye Liu <liuye@kylinos.cn>
---
 mm/vmalloc.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/mm/vmalloc.c b/mm/vmalloc.c
index a888eca016a8..59ba203a4eff 100644
--- a/mm/vmalloc.c
+++ b/mm/vmalloc.c
@@ -4906,6 +4906,7 @@ int remap_vmalloc_range_partial(struct vm_area_struct *vma, unsigned long uaddr,
 		struct page *page = vmalloc_to_page(kaddr);
 		int ret;
 
+		WARN_ON(!page);
 		ret = vm_insert_page(vma, uaddr, page);
 		if (ret)
 			return ret;

-- 
2.43.0