On Thursday, December 01, 2016 05:16:00 PM Aaron Sierra wrote: > ----- Original Message ----- > > From: "Thomas Gleixner" <tglx@xxxxxxxxxxxxx> > > Sent: Thursday, December 1, 2016 8:52:48 AM > > > On Wed, 30 Nov 2016, Aaron Sierra wrote: > >> When testing GPE interrupts with CONFIG_PREEMPT_RT_FULL enabled, a > >> verbose WARN_ONCE message would print to the kernel log. It turned out > >> that the GPE interrupt handler was being called with local interrupts > >> enabled because acpi_gbl_gpe_lock was implemented as a spinlock_t. Full > >> preemption strips local interrupt disabling from spinlock_t operations, > >> but not for raw_spinlock_t operations. > >> > >> This is the warning that was triggered: > >> > >> ------------[ cut here ]------------ > >> WARNING: CPU: 8 PID: 483 at kernel/irq/handle.c:149 > >> __handle_irq_event_percpu+0x6f/0xcf > >> irq 33 handler irq_default_primary_handler+0x0/0xb enabled interrupts > >> Modules linked in: gpio_irq_demo(O) > >> CPU: 8 PID: 483 Comm: irq/9-acpi Tainted: G O > >> 4.8.6-rt5-00012-geaa3b7c #6 > >> Hardware name: Extreme Engineering Solutions, Inc. XCalibur4643/XCalibur4643, > >> BIOS 1-1.1.12.3_Alpha 04/29/2016 > >> 0000000000000000 ffff880858f3bc10 ffffffff81219a93 ffff880858f3bc60 > >> 0000000000000000 ffff880858f3bc50 ffffffff8104b84a 0000009500000000 > >> ffff880855b76880 0000000000000021 0000000000000002 ffff880856356800 > >> Call Trace: > >> [<ffffffff81219a93>] dump_stack+0x4d/0x63 > >> [<ffffffff8104b84a>] __warn+0xc0/0xdb > >> [<ffffffff8104b8af>] warn_slowpath_fmt+0x4a/0x4c > >> [<ffffffff810f7192>] ? path_openat+0xbf8/0xc62 > >> [<ffffffff8107d7c3>] ? handle_irq_event+0x75/0x75 > >> [<ffffffff8107d68d>] __handle_irq_event_percpu+0x6f/0xcf > >> [<ffffffff8107d727>] handle_irq_event_percpu+0x3a/0x61 > >> [<ffffffff8107d7a3>] handle_irq_event+0x55/0x75 > >> [<ffffffff8107ff76>] handle_simple_irq+0x5c/0x92 > >> [<ffffffff81243a53>] gpe_irq_handler+0x2a/0x31 > > > > gpe_irq_handler is not in tree, so I really cannot tell what this is > > about. It looks like it does interrupt demultiplexing, which triggers the > > warning. > > Thomas, > Your guess is correct, this involves a currently out-of-tree extension to > the gpio-ich driver which allows GPIO pins to be mapped to IRQs by demuxing > their corresponding GPE events. > > The gpio_irq_demo module requests a GPIO pin, converts it to an IRQ using > gpio_to_irq() and registers a trivial handler against the IRQ. And what does it have to do with GPEs, if I may ask? In the future, please CC all ACPI-related changes to linux-acpi@xxxxxxxxxxxxxxx. Thanks, Rafael -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
