This is a note to let you know that I've just added the patch titled
sched: Fix hotplug vs. set_cpus_allowed_ptr()
to the 3.4-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:
sched-fix-hotplug-vs.-set_cpus_allowed_ptr.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 6acbfb96976fc3350e30d964acb1dbbdf876d55e Mon Sep 17 00:00:00 2001
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Date: Fri, 16 May 2014 11:50:42 +0800
Subject: sched: Fix hotplug vs. set_cpus_allowed_ptr()
From: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
commit 6acbfb96976fc3350e30d964acb1dbbdf876d55e upstream.
Lai found that:
WARNING: CPU: 1 PID: 13 at arch/x86/kernel/smp.c:124 native_smp_send_reschedule+0x2d/0x4b()
...
migration_cpu_stop+0x1d/0x22
was caused by set_cpus_allowed_ptr() assuming that cpu_active_mask is
always a sub-set of cpu_online_mask.
This isn't true since 5fbd036b552f ("sched: Cleanup cpu_active madness").
So set active and online at the same time to avoid this particular
problem.
Fixes: 5fbd036b552f ("sched: Cleanup cpu_active madness")
Signed-off-by: Lai Jiangshan <laijs@xxxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Gautham R. Shenoy <ego@xxxxxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Michael wang <wangyun@xxxxxxxxxxxxxxxxxx>
Cc: Paul Gortmaker <paul.gortmaker@xxxxxxxxxxxxx>
Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Cc: Srivatsa S. Bhat <srivatsa.bhat@xxxxxxxxxxxxxxxxxx>
Cc: Toshi Kani <toshi.kani@xxxxxx>
Link: http://lkml.kernel.org/r/53758B12.8060609@xxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/cpu.c | 6 ++++--
kernel/sched/core.c | 1 -
2 files changed, 4 insertions(+), 3 deletions(-)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -631,10 +631,12 @@ void set_cpu_present(unsigned int cpu, b
void set_cpu_online(unsigned int cpu, bool online)
{
- if (online)
+ if (online) {
cpumask_set_cpu(cpu, to_cpumask(cpu_online_bits));
- else
+ cpumask_set_cpu(cpu, to_cpumask(cpu_active_bits));
+ } else {
cpumask_clear_cpu(cpu, to_cpumask(cpu_online_bits));
+ }
}
void set_cpu_active(unsigned int cpu, bool active)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5656,7 +5656,6 @@ static int __cpuinit sched_cpu_active(st
unsigned long action, void *hcpu)
{
switch (action & ~CPU_TASKS_FROZEN) {
- case CPU_STARTING:
case CPU_DOWN_FAILED:
set_cpu_active((long)hcpu, true);
return NOTIFY_OK;
Patches currently in stable-queue which might be from laijs@xxxxxxxxxxxxxx are
queue-3.4/sched-fix-hotplug-vs.-set_cpus_allowed_ptr.patch
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