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    ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled · 697091f9
    Tony Lindgren authored
    [ Upstream commit 06862d78 ]
    
    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 1098582a ("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 50d6b3cf
    
     ("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: default avatarPaul E. McKenney <paulmck@kernel.org>
    Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
    Signed-off-by: default avatarSasha Levin <sashal@kernel.org>
    697091f9