If debugfs were to return a non-NULL error for a debugfs call, using
that pointer later in debugfs_create_files() would crash.
Fix that by properly checking the pointer before referencing it.
Reported-by: Michal Hocko <mhocko@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
block/blk-mq-debugfs.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/block/blk-mq-debugfs.c b/block/blk-mq-debugfs.c
index 90d68760af08..777638f597aa 100644
--- a/block/blk-mq-debugfs.c
+++ b/block/blk-mq-debugfs.c
@@ -838,6 +838,9 @@ static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
static bool debugfs_create_files(struct dentry *parent, void *data,
const struct blk_mq_debugfs_attr *attr)
{
+ if (IS_ERR_OR_NULL(parent))
+ return false;
+
d_inode(parent)->i_private = data;
for (; attr->name; attr++) {
--
2.20.1
