3.8.13.13-rt26-rc1 stable review patch.
If anyone has any objections, please let me know.
------------------
From: Tiejun Chen <tiejun.c...@windriver.com>
Commit 08c1ab68, "hotplug-use-migrate-disable.patch", intends to
use migrate_enable()/migrate_disable() to replace that combination
of preempt_enable() and preempt_disable(), but actually in
!CONFIG_PREEMPT_RT_FULL case, migrate_enable()/migrate_disable()
are still equal to preempt_enable()/preempt_disable(). So that
followed cpu_hotplug_begin()/cpu_unplug_begin(cpu) would go schedule()
to trigger schedule_debug() like this:
_cpu_down()
|
+ migrate_disable() = preempt_disable()
|
+ cpu_hotplug_begin() or cpu_unplug_begin()
|
+ schedule()
|
+ __schedule()
|
+ preempt_disable();
|
+ __schedule_bug() is true!
So we should move migrate_enable() as the original scheme.
Cc: stable...@vger.kernel.org
Signed-off-by: Tiejun Chen <tiejun.c...@windriver.com>
Signed-off-by: Steven Rostedt <rost...@goodmis.org>
---
kernel/cpu.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 98f2ea3..da6e128 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -594,6 +594,7 @@ static int __ref _cpu_down(unsigned int cpu, int
tasks_frozen)
err = -EBUSY;
goto restore_cpus;
}
+ migrate_enable();
cpu_hotplug_begin();
err = cpu_unplug_begin(cpu);
@@ -647,7 +648,6 @@ static int __ref _cpu_down(unsigned int cpu, int
tasks_frozen)
out_release:
cpu_unplug_done(cpu);
out_cancel:
- migrate_enable();
cpu_hotplug_done();
if (!err)
cpu_notify_nofail(CPU_POST_DEAD | mod, hcpu);
--
1.8.4.3
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