With rw_page, page_endio is used for completing IO on a page
and it propagates write error to the address space if the IO
fails. The problem is it accesses page->mapping directly which
might be okay for file-backed pages but it shouldn't for
anonymous page. Otherwise, it can corrupt one of field from
anon_vma under us and system goes panic randomly.
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx>
---
mm/filemap.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 2ba46f410c7c..1944c631e3e6 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1008,9 +1008,12 @@ void page_endio(struct page *page, bool is_write, int err)
unlock_page(page);
} else {
if (err) {
+ struct address_space *mapping;
+
SetPageError(page);
- if (page->mapping)
- mapping_set_error(page->mapping, err);
+ mapping = page_mapping(page);
+ if (mapping)
+ mapping_set_error(mapping, err);
}
end_page_writeback(page);
}
--
2.7.4