Hi,
On 24/07/2019 09:43, Jia-Ju Bai wrote:
In gfs2_alloc_inode(), when kmem_cache_alloc() on line 1724 returns
NULL, ip is assigned to NULL. In this case, "return &ip->i_inode" will
cause a null-pointer dereference.
To fix this null-pointer dereference, NULL is returned when ip is NULL.
This bug is found by a static analysis tool STCheck written by us.
The bug is in the tool I'm afraid. Since i_inode is the first element of
ip, there is no NULL dereference here. A pointer to ip->i_inode and a
pointer to ip are one and the same (bar the differing types) which is
the reason that we return &ip->i_inode rather than just ip,
Steve.
Signed-off-by: Jia-Ju Bai <baijiaju1...@gmail.com>
---
fs/gfs2/super.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/fs/gfs2/super.c b/fs/gfs2/super.c
index 0acc5834f653..c07c3f4f8451 100644
--- a/fs/gfs2/super.c
+++ b/fs/gfs2/super.c
@@ -1728,8 +1728,9 @@ static struct inode *gfs2_alloc_inode(struct super_block
*sb)
memset(&ip->i_res, 0, sizeof(ip->i_res));
RB_CLEAR_NODE(&ip->i_res.rs_node);
ip->i_rahead = 0;
- }
- return &ip->i_inode;
+ return &ip->i_inode;
+ } else
+ return NULL;
}
static void gfs2_free_inode(struct inode *inode)
