Messages in this thread Patch in this message | | | Date | Tue, 10 Dec 2013 19:46:32 -0500 | From | Steven Rostedt <> | Subject | [PATCH RT 1/5] cpu_down: move migrate_enable() back |
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3.8.13.13-rt26-rc1 stable review patch. If anyone has any objections, please let me know.
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From: Tiejun Chen <tiejun.chen@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-rt@vger.kernel.org Signed-off-by: Tiejun Chen <tiejun.chen@windriver.com> Signed-off-by: Steven Rostedt <rostedt@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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