[PATCH] ext4: fix error pointer dereference in ext4_mb_load_buddy_gfp()

[Dan Carpenter]

This code calls folio_put() on an error pointer which will lead to a
crash.  Check for both error pointers and NULL pointers before calling
folio_put().

Fixes: 5eea586b47f0 ("ext4: convert bd_buddy_page to bd_buddy_folio")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
---
 fs/ext4/mballoc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 648989c125f2..9dda9cd68ab2 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -1717,7 +1717,7 @@ ext4_mb_load_buddy_gfp(struct super_block *sb, ext4_group_t group,
 	return 0;
 
 err:
-	if (folio)
+	if (!IS_ERR_OR_NULL(folio))
 		folio_put(folio);
 	if (e4b->bd_bitmap_folio)
 		folio_put(e4b->bd_bitmap_folio);
-- 
2.43.0