From 71e93d15612c61c2e26a169567becf088e71b8ff Mon Sep 17 00:00:00 2001 From: Venki Pallipadi Date: Thu, 13 Mar 2008 17:18:19 -0700 Subject: [PATCH] ACPI: lockdep warning on boot, 2.6.25-rc5 This avoids the harmless WARNING by lockdep in acpi_processor_idle(). The reason for WARNING is because at the depth of idle handling code, some of the idle handlers disable interrupts, some times, while returning from the idle handler. After return, acpi_processor_idle and few other routines in the file did an unconditional local_irq_enable(). With LOCKDEP, enabling irq when it is already enabled generates the below WARNING. > > [ 0.593038] ------------[ cut here ]------------ > > [ 0.593267] WARNING: at kernel/lockdep.c:2035 trace_hardirqs_on+0xa0/0x115() > > [ 0.593596] Modules linked in: > > [ 0.593756] Pid: 0, comm: swapper Not tainted 2.6.25-rc5 #8 > > [ 0.594017] > > [ 0.594017] Call Trace: > > [ 0.594216] [] warn_on_slowpath+0x58/0x6b > > [ 0.594495] [] ? _spin_unlock_irqrestore+0x38/0x47 > > [ 0.594809] [] ? acpi_os_release_lock+0x9/0xb > > [ 0.595103] [] ? acpi_set_register+0x161/0x173 > > [ 0.595401] [] ? acpi_processor_idle+0x1de/0x546 > > [ 0.595706] [] ? default_idle+0x0/0x73 > > [ 0.595970] [] trace_hardirqs_on+0xa0/0x115 > > [ 0.596049] [] ? acpi_processor_idle+0x0/0x546 > > [ 0.596346] [] acpi_processor_idle+0x1de/0x546 > > [ 0.596642] [] ? default_idle+0x0/0x73 > > [ 0.596912] [] ? acpi_processor_idle+0x0/0x546 > > [ 0.597209] [] ? default_idle+0x0/0x73 > > [ 0.597472] [] cpu_idle+0xa7/0xd1 > > [ 0.597717] [] rest_init+0x55/0x57 > > [ 0.597957] [] start_kernel+0x29d/0x2a8 > > [ 0.598215] [] _sinittext+0x1da/0x1e1 > > [ 0.598464] > > [ 0.598546] ---[ end trace 778e504de7e3b1e3 ]--- Signed-off-by: Venkatesh Pallipadi Signed-off-by: Len Brown --- drivers/acpi/processor_idle.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c index 6f3b217699e9..e8e2d8869236 100644 --- a/drivers/acpi/processor_idle.c +++ b/drivers/acpi/processor_idle.c @@ -216,8 +216,10 @@ static void acpi_safe_halt(void) * test NEED_RESCHED: */ smp_mb(); - if (!need_resched()) + if (!need_resched()) { safe_halt(); + local_irq_disable(); + } current_thread_info()->status |= TS_POLLING; } @@ -421,7 +423,9 @@ static void acpi_processor_idle(void) else acpi_safe_halt(); - local_irq_enable(); + if (irqs_disabled()) + local_irq_enable(); + return; } @@ -530,7 +534,9 @@ static void acpi_processor_idle(void) * skew otherwise. */ sleep_ticks = 0xFFFFFFFF; - local_irq_enable(); + if (irqs_disabled()) + local_irq_enable(); + break; case ACPI_STATE_C2: -- 2.20.1