[RFC][PATCH 4/5] shmem: Avoid segfault in shmem_read_mapping_page_gfp()

Roberto Sassu
2021-11-12T12:45:01Z

Check the hwpoison page flag only if the page is valid in
shmem_read_mapping_page_gfp(). The PageHWPoison() macro tries to access
the page flags and cannot work on an error pointer.

Signed-off-by: Roberto Sassu <roberto.sassu@huawei.com>
---
mm/shmem.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/shmem.c b/mm/shmem.c
index 23c91a8beb78..427863cbf0dc 100644
--- a/mm/shmem.c
+++ b/mm/shmem.c
@@ -4222,7 +4222,7 @@ struct page *shmem_read_mapping_page_gfp(struct address_space *mapping,
else
unlock_page(page);

- if (PageHWPoison(page))
+ if (!IS_ERR(page) && PageHWPoison(page))
page = ERR_PTR(-EIO);

return page;
--
2.32.0