The arm boot_lock is used by the secondary processor startup code. The locking task is the idle thread, which has idle->sched_class == &idle_sched_class. idle_sched_class->enqueue_task == NULL, so if the idle task blocks on the lock, the attempt to wake it when the lock becomes available will fail: try_to_wake_up() ... activate_task() enqueue_task() p->sched_class->enqueue_task(rq, p, flags) Fix by converting boot_lock to a raw spin lock. Signed-off-by: Frank Rowand <frank.rowand@xxxxxxxxxxx> --- arch/arm/mach-exynos4/platsmp.c | 10 5 + 5 - 0 ! arch/arm/mach-msm/platsmp.c | 10 5 + 5 - 0 ! arch/arm/mach-omap2/omap-smp.c | 10 5 + 5 - 0 ! arch/arm/mach-tegra/platsmp.c | 10 5 + 5 - 0 ! arch/arm/mach-ux500/platsmp.c | 10 5 + 5 - 0 ! arch/arm/plat-versatile/platsmp.c | 10 5 + 5 - 0 ! 6 files changed, 30 insertions(+), 30 deletions(-) Index: b/arch/arm/plat-versatile/platsmp.c =================================================================== --- a/arch/arm/plat-versatile/platsmp.c +++ b/arch/arm/plat-versatile/platsmp.c @@ -37,7 +37,7 @@ static void __cpuinit write_pen_release( outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); } -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { @@ -57,8 +57,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -69,7 +69,7 @@ int __cpuinit boot_secondary(unsigned in * Set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* * This is really belt and braces; we hold unintended secondary @@ -99,7 +99,7 @@ int __cpuinit boot_secondary(unsigned in * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return pen_release != -1 ? -ENOSYS : 0; } Index: b/arch/arm/mach-exynos4/platsmp.c =================================================================== --- a/arch/arm/mach-exynos4/platsmp.c +++ b/arch/arm/mach-exynos4/platsmp.c @@ -56,7 +56,7 @@ static void __iomem *scu_base_addr(void) return (void __iomem *)(S5P_VA_SCU); } -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { @@ -76,8 +76,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -88,7 +88,7 @@ int __cpuinit boot_secondary(unsigned in * Set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* * The secondary processor is waiting to be released from @@ -120,7 +120,7 @@ int __cpuinit boot_secondary(unsigned in * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return pen_release != -1 ? -ENOSYS : 0; } Index: b/arch/arm/mach-msm/platsmp.c =================================================================== --- a/arch/arm/mach-msm/platsmp.c +++ b/arch/arm/mach-msm/platsmp.c @@ -38,7 +38,7 @@ extern void msm_secondary_startup(void); */ volatile int pen_release = -1; -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { @@ -62,8 +62,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } static __cpuinit void prepare_cold_cpu(unsigned int cpu) @@ -100,7 +100,7 @@ int __cpuinit boot_secondary(unsigned in * set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* * The secondary processor is waiting to be released from @@ -134,7 +134,7 @@ int __cpuinit boot_secondary(unsigned in * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return pen_release != -1 ? -ENOSYS : 0; } Index: b/arch/arm/mach-omap2/omap-smp.c =================================================================== --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -29,7 +29,7 @@ /* SCU base address */ static void __iomem *scu_base; -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { @@ -43,8 +43,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -53,7 +53,7 @@ int __cpuinit boot_secondary(unsigned in * Set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* * Update the AuxCoreBoot0 with boot state for secondary core. @@ -70,7 +70,7 @@ int __cpuinit boot_secondary(unsigned in * Now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return 0; } Index: b/arch/arm/mach-tegra/platsmp.c =================================================================== --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -29,7 +29,7 @@ extern void tegra_secondary_startup(void); -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); static void __iomem *scu_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE); #define EVP_CPU_RESET_VECTOR \ @@ -51,8 +51,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -66,7 +66,7 @@ int __cpuinit boot_secondary(unsigned in * set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* set the reset vector to point to the secondary_startup routine */ @@ -102,7 +102,7 @@ int __cpuinit boot_secondary(unsigned in * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return 0; } Index: b/arch/arm/mach-ux500/platsmp.c =================================================================== --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -57,7 +57,7 @@ static void __iomem *scu_base_addr(void) return NULL; } -static DEFINE_SPINLOCK(boot_lock); +static DEFINE_RAW_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { @@ -77,8 +77,8 @@ void __cpuinit platform_secondary_init(u /* * Synchronise with the boot thread. */ - spin_lock(&boot_lock); - spin_unlock(&boot_lock); + raw_spin_lock(&boot_lock); + raw_spin_unlock(&boot_lock); } int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) @@ -89,7 +89,7 @@ int __cpuinit boot_secondary(unsigned in * set synchronisation state between this boot processor * and the secondary one */ - spin_lock(&boot_lock); + raw_spin_lock(&boot_lock); /* * The secondary processor is waiting to be released from @@ -110,7 +110,7 @@ int __cpuinit boot_secondary(unsigned in * now the secondary core is starting up let it run its * calibrations, then wait for it to finish */ - spin_unlock(&boot_lock); + raw_spin_unlock(&boot_lock); return pen_release != -1 ? 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