ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled
authorTony Lindgren <tony@atomide.com>
Sun, 10 Jan 2021 19:09:11 +0000 (21:09 +0200)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 17 Feb 2021 10:02:22 +0000 (11:02 +0100)
commit697091f92727bc9be5e81a42ecc361dce00a3374
tree7ebb630c92f606a8a6349e9d6fc748639050cd6a
parent6c152ac1b687fc5868ac2011ee1e3597f2213c08
ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled

[ Upstream commit 06862d789ddde8a99c1e579e934ca17c15a84755 ]

We get suspcious RCU usage splats with cpuidle in several places in
omap_enter_idle_coupled() with the kernel debug options enabled:

RCU used illegally from extended quiescent state!
...
(_raw_spin_lock_irqsave)
(omap_enter_idle_coupled+0x17c/0x2d8)
(omap_enter_idle_coupled)
(cpuidle_enter_state)
(cpuidle_enter_state_coupled)
(cpuidle_enter)

Let's use RCU_NONIDLE to suppress these splats. Things got changed around
with commit 1098582a0f6c ("sched,idle,rcu: Push rcu_idle deeper into the
idle path") that started triggering these warnings.

For the tick_broadcast related calls, ideally we'd just switch over to
using CPUIDLE_FLAG_TIMER_STOP for omap_enter_idle_coupled() to have the
generic cpuidle code handle the tick_broadcast related calls for us and
then just drop the tick_broadcast calls here.

But we're currently missing the call in the common cpuidle code for
tick_broadcast_enable() that CPU1 hotplug needs as described in earlier
commit 50d6b3cf9403 ("ARM: OMAP2+: fix lack of timer interrupts on CPU1
after hotplug").

Cc: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Paul E. McKenney <paulmck@kernel.org>
Cc: Russell King <rmk+kernel@armlinux.org.uk>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Tony Lindgren <tony@atomide.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
arch/arm/mach-omap2/cpuidle44xx.c