Messages in this thread Patch in this message | | | From | xkernel.wang@foxmail ... | Subject | [PATCH] erofs: fix a potential NULL dereference of alloc_pages() | Date | Tue, 22 Mar 2022 16:08:12 +0800 |
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From: Xiaoke Wang <xkernel.wang@foxmail.com>
alloc_pages() returns the page on success or NULL if allocation fails, while set_page_private() will dereference `newpage`. So it is better to catch the memory error in case other errors happen.
Signed-off-by: Xiaoke Wang <xkernel.wang@foxmail.com> --- fs/erofs/zdata.c | 14 +++++++++----- 1 file changed, 9 insertions(+), 5 deletions(-)
diff --git a/fs/erofs/zdata.c b/fs/erofs/zdata.c index 11c7a1a..36a5421 100644 --- a/fs/erofs/zdata.c +++ b/fs/erofs/zdata.c @@ -735,11 +735,15 @@ static int z_erofs_do_read_page(struct z_erofs_decompress_frontend *fe, struct page *const newpage = alloc_page(GFP_NOFS | __GFP_NOFAIL); - set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE); - err = z_erofs_attach_page(clt, newpage, - Z_EROFS_PAGE_TYPE_EXCLUSIVE); - if (!err) - goto retry; + if (!newpage) { + err = -ENOMEM; + } else { + set_page_private(newpage, Z_EROFS_SHORTLIVED_PAGE); + err = z_erofs_attach_page(clt, newpage, + Z_EROFS_PAGE_TYPE_EXCLUSIVE); + if (!err) + goto retry; + } } if (err) --
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