This is a note to let you know that I've just added the patch titled
ARM: fix rcu stalls on SMP platforms
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
arm-fix-rcu-stalls-on-smp-platforms.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.
>From 7deabca0acfe02b8e18f59a4c95676012f49a304 Mon Sep 17 00:00:00 2001
From: Russell King <[email protected]>
Date: Thu, 19 Jan 2012 15:20:58 +0000
Subject: ARM: fix rcu stalls on SMP platforms
From: Russell King <[email protected]>
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]>
Signed-off-by: UCHINO Satoshi <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
---
arch/arm/kernel/smp.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -445,9 +445,7 @@ static DEFINE_PER_CPU(struct clock_event
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
@@ -568,7 +566,9 @@ asmlinkage void __exception_irq_entry do
switch (ipinr) {
case IPI_TIMER:
+ irq_enter();
ipi_timer();
+ irq_exit();
break;
case IPI_RESCHEDULE:
@@ -576,15 +576,21 @@ asmlinkage void __exception_irq_entry do
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:
Patches currently in stable-queue which might be from
[email protected] are
queue-3.0/arm-fix-rcu-stalls-on-smp-platforms.patch
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