commit d0cb50185ae942b03c4327be322055d622dc79f6 upstream.

[ Fixes: CVE-2020-8428 ]

may_create_in_sticky() call is done when we already have dropped the
reference to dir.

Fixes: 30aba665 (namei: allow restricted O_CREAT of FIFOs and regular files)
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: NShile Zhang <shile.zhang@linux.alibaba.com>
Acked-by: NJoseph Qi <joseph.qi@linux.alibaba.com>