From: Russell King <[email protected]> Date: Thu, 19 Jan 2012 15:20:58 +0000
commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream. We can stall RCU processing on SMP platforms if a CPU sits in its idle loop for a long time. This happens because we don't call irq_enter() and irq_exit() around generic_smp_call_function_interrupt() and friends. Add the necessary calls, and remove the one from within ipi_timer(), so that they're all in a common place. Signed-off-by: Russell King <[email protected]> [add irq_enter()/irq_exit() in do_local_timer] Signed-off-by: UCHINO Satoshi <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]> --- Greg, please replace the arm-fix-rcu-stalls-on-smp-platforms.patch in the queue-3.0 subdirectory with this. Thanks, Uchino --- arch/arm/kernel/smp.c | 12 ++++++++++-- 1 files changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index fea97f6..4469924 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -445,9 +445,7 @@ static DEFINE_PER_CPU(struct clock_event_device, percpu_clockevent); static void ipi_timer(void) { struct clock_event_device *evt = &__get_cpu_var(percpu_clockevent); - irq_enter(); evt->event_handler(evt); - irq_exit(); } #ifdef CONFIG_LOCAL_TIMERS @@ -458,7 +456,9 @@ asmlinkage void __exception_irq_entry do_local_timer(struct pt_regs *regs) if (local_timer_ack()) { __inc_irq_stat(cpu, local_timer_irqs); + irq_enter(); ipi_timer(); + irq_exit(); } set_irq_regs(old_regs); @@ -568,7 +568,9 @@ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs) switch (ipinr) { case IPI_TIMER: + irq_enter(); ipi_timer(); + irq_exit(); break; case IPI_RESCHEDULE: @@ -576,15 +578,21 @@ asmlinkage void __exception_irq_entry do_IPI(int ipinr, struct pt_regs *regs) break; case IPI_CALL_FUNC: + irq_enter(); generic_smp_call_function_interrupt(); + irq_exit(); break; case IPI_CALL_FUNC_SINGLE: + irq_enter(); generic_smp_call_function_single_interrupt(); + irq_exit(); break; case IPI_CPU_STOP: + irq_enter(); ipi_cpu_stop(cpu); + irq_exit(); break; default: -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
