preempt_rt kernel forces all irq interrupts to be threaded except some special interrupts. This cascade interrupt belongs to the exceptions.
Because irq2 is initialized more early than "kthreadd" task, which converts irq interrupt to threaded. If this irq is threaded, kernel calls "try_to_wake_up" function to wake up "kthreadd" task, but at that moment, "kthreadd" task hasn't been initialized well, so try_to_wake_up wakes up a NULL task. Signed-off-by: Liming Wang <[email protected]> --- arch/mips/kernel/i8259.c | 1 + 1 files changed, 1 insertions(+), 0 deletions(-) diff --git a/arch/mips/kernel/i8259.c b/arch/mips/kernel/i8259.c index 5c74eb7..fb338db 100644 --- a/arch/mips/kernel/i8259.c +++ b/arch/mips/kernel/i8259.c @@ -295,6 +295,7 @@ static void init_8259A(int auto_eoi) static struct irqaction irq2 = { .handler = no_action, .name = "cascade", + .flags = IRQF_NO_THREAD, }; static struct resource pic1_io_resource = { -- 1.7.0.4 _______________________________________________ yocto mailing list [email protected] https://lists.yoctoproject.org/listinfo/yocto
