debugobjects: Do not fill_pool() if pi_blocked_on

debugobjects: Do not fill_pool() if pi_blocked_on

On RT enabled kernels, fill_pool() ends up calling rtlock_lock(), which
asserts if current::pi_blocked_on is set, because a task can obviously only
block on one lock as otherwise the priority inheritenace chain gets
corrupted.

Prevent this by expanding the conditional to take current::pi_blocked_on
into account.

Fixes: 4bedcc28469a ("debugobjects: Make them PREEMPT_RT aware")
Reported-by: syzbot+b8ca586b9fc235f0c0df@syzkaller.appspotmail.com
Signed-off-by: Helen Koike <koike@igalia.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260511215359.3351259-1-koike@igalia.com
Closes: https://syzkaller.appspot.com/bug?extid=b8ca586b9fc235f0c0df