| Message ID | 20210108134105.58543-1-tony@atomide.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | ARM: OMAP2+: Fix suspcious RCU usage splats for omap_enter_idle_coupled | expand |
On Fri, Jan 08, 2021 at 03:41:05PM +0200, Tony Lindgren wrote: > 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> > Signed-off-by: Tony Lindgren <tony@atomide.com> From an RCU viewpoint: Acked-by: Paul E. McKenney <paulmck@kernel.org> > --- > arch/arm/mach-omap2/cpuidle44xx.c | 16 ++++++++-------- > 1 file changed, 8 insertions(+), 8 deletions(-) > > diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c > --- a/arch/arm/mach-omap2/cpuidle44xx.c > +++ b/arch/arm/mach-omap2/cpuidle44xx.c > @@ -151,10 +151,10 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, > (cx->mpu_logic_state == PWRDM_POWER_OFF); > > /* Enter broadcast mode for periodic timers */ > - tick_broadcast_enable(); > + RCU_NONIDLE(tick_broadcast_enable()); > > /* Enter broadcast mode for one-shot timers */ > - tick_broadcast_enter(); > + RCU_NONIDLE(tick_broadcast_enter()); > > /* > * Call idle CPU PM enter notifier chain so that > @@ -166,7 +166,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, > > if (dev->cpu == 0) { > pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); > - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); > + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); > > /* > * Call idle CPU cluster PM enter notifier chain > @@ -179,7 +179,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, > index = 1; > cx = state_ptr + index; > pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); > - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); > + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); > mpuss_can_lose_context = 0; > } > } > @@ -195,9 +195,9 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, > mpuss_can_lose_context) > gic_dist_disable(); > > - clkdm_deny_idle(cpu_clkdm[1]); > - omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON); > - clkdm_allow_idle(cpu_clkdm[1]); > + RCU_NONIDLE(clkdm_deny_idle(cpu_clkdm[1])); > + RCU_NONIDLE(omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON)); > + RCU_NONIDLE(clkdm_allow_idle(cpu_clkdm[1])); > > if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && > mpuss_can_lose_context) { > @@ -225,7 +225,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, > cpu_pm_exit(); > > cpu_pm_out: > - tick_broadcast_exit(); > + RCU_NONIDLE(tick_broadcast_exit()); > > fail: > cpuidle_coupled_parallel_barrier(dev, &abort_barrier); > -- > 2.30.0
diff --git a/arch/arm/mach-omap2/cpuidle44xx.c b/arch/arm/mach-omap2/cpuidle44xx.c --- a/arch/arm/mach-omap2/cpuidle44xx.c +++ b/arch/arm/mach-omap2/cpuidle44xx.c @@ -151,10 +151,10 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, (cx->mpu_logic_state == PWRDM_POWER_OFF); /* Enter broadcast mode for periodic timers */ - tick_broadcast_enable(); + RCU_NONIDLE(tick_broadcast_enable()); /* Enter broadcast mode for one-shot timers */ - tick_broadcast_enter(); + RCU_NONIDLE(tick_broadcast_enter()); /* * Call idle CPU PM enter notifier chain so that @@ -166,7 +166,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, if (dev->cpu == 0) { pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); /* * Call idle CPU cluster PM enter notifier chain @@ -179,7 +179,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, index = 1; cx = state_ptr + index; pwrdm_set_logic_retst(mpu_pd, cx->mpu_logic_state); - omap_set_pwrdm_state(mpu_pd, cx->mpu_state); + RCU_NONIDLE(omap_set_pwrdm_state(mpu_pd, cx->mpu_state)); mpuss_can_lose_context = 0; } } @@ -195,9 +195,9 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, mpuss_can_lose_context) gic_dist_disable(); - clkdm_deny_idle(cpu_clkdm[1]); - omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON); - clkdm_allow_idle(cpu_clkdm[1]); + RCU_NONIDLE(clkdm_deny_idle(cpu_clkdm[1])); + RCU_NONIDLE(omap_set_pwrdm_state(cpu_pd[1], PWRDM_POWER_ON)); + RCU_NONIDLE(clkdm_allow_idle(cpu_clkdm[1])); if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD) && mpuss_can_lose_context) { @@ -225,7 +225,7 @@ static int omap_enter_idle_coupled(struct cpuidle_device *dev, cpu_pm_exit(); cpu_pm_out: - tick_broadcast_exit(); + RCU_NONIDLE(tick_broadcast_exit()); fail: cpuidle_coupled_parallel_barrier(dev, &abort_barrier);
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> Signed-off-by: Tony Lindgren <tony@atomide.com> --- arch/arm/mach-omap2/cpuidle44xx.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-)