A potential coding issue was:

 Reported-by: Zheng Yejian [off-list ref]

This set should solve it.

Peter Zijlstra (1):
  futex: Change locking rules

Thomas Gleixner (2):
  futex: Ensure the correct return value from futex_lock_pi()
  futex: Cure exit race

 kernel/futex.c | 233 +++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 189 insertions(+), 44 deletions(-)

Cc: bigeasy@linutronix.de
Cc: bristot@redhat.com
Cc: Darren Hart <dvhart@infradead.org>
Cc: dvhart@infradead.org
Cc: Heiko Carstens <redacted>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: jdesfossez@efficios.com
Cc: juri.lelli@arm.com
Cc: mathieu.desnoyers@efficios.com
Cc: rostedt@goodmis.org
Cc: Sasha Levin <sashal@kernel.org>
Cc: stable@vger.kernel.org
Cc: xlpang@redhat.com
-- 
2.25.1