From: Greg Kroah-Hartman gregkh@linuxfoundation.org
[ Upstream commit 36991ca68db9dd43bac7f3519f080ee3939263ef ]
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@kernel.org Reported-and-tested-by: syzbot+b382ba6a802a3d242790@syzkaller.appspotmail.com Reported-by: Tetsuo Handa penguin-kernel@I-love.SAKURA.ne.jp Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Sasha Levin sashal@kernel.org --- 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 d95439154556d..da0453277f7f2 100644 --- a/block/blk-mq-debugfs.c +++ b/block/blk-mq-debugfs.c @@ -791,6 +791,9 @@ 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++) {