[PATCH 0/1] mips/rt: convert cascade interrupt to no threaded

[PATCH 0/1] mips/rt: convert cascade interrupt to no threaded

[Liming Wang]

This patch fixes yocto bug:
[Bug 1392] qemumips: linux-yocto-rt_3.0 panics at boot

Liming Wang (1):
      mips/rt: convert cascade interrupt to no threaded

 arch/mips/kernel/i8259.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

[PATCH 1/1] mips/rt: convert cascade interrupt to no threaded

[Liming Wang]

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 <liming.wang@windriver.com>
---
 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

Re: [PATCH 0/1] mips/rt: convert cascade interrupt to no threaded

[Bruce Ashfield]

On 11-08-25 03:55 AM, Liming Wang wrote:
> This patch fixes yocto bug:
> [Bug 1392] qemumips: linux-yocto-rt_3.0 panics at boot

Ack'd. I do recall a similar fix for mips back in the
2.6.27 days. Both for this and the timer interrupt.

Will merge this shortly.

Bruce


>
> Liming Wang (1):
>        mips/rt: convert cascade interrupt to no threaded
>
>   arch/mips/kernel/i8259.c |    1 +
>   1 files changed, 1 insertions(+), 0 deletions(-)
>