[ Upstream commit 4e240d1b ]

If namelen is corrupted to have very long value, fill_dentries can copy
wrong memory area.
Reviewed-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>