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UPSTREAM: cpu/hotplug: Handle unbalanced hotplug enable/disable

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(cherry picked from commit 01b4115906)

When cpu_hotplug_enable() is called unbalanced w/o a preceeding
cpu_hotplug_disable() the code emits a warning, but happily decrements the
disabled counter. This causes the next operations to malfunction.

Prevent the decrement and just emit a warning.

Signed-off-by: Lianwei Wang <lianwei.wang@gmail.com>
Cc: peterz@infradead.org
Cc: linux-pm@vger.kernel.org
Cc: oleg@redhat.com
Link: http://lkml.kernel.org/r/1465541008-12476-1-git-send-email-lianwei.wang@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Lianwei Wang 2016-06-09 23:43:28 -07:00 committed by Amit Pundir
parent 279ddc1c9c
commit 9d37de65aa
1 changed files with 9 additions and 2 deletions
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11
kernel/cpu.c
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@ -185,10 +185,17 @@ void cpu_hotplug_disable(void)
}
EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
static void __cpu_hotplug_enable(void)
{
if (WARN_ONCE(!cpu_hotplug_disabled, "Unbalanced cpu hotplug enable\n"))
return;
cpu_hotplug_disabled--;
}
void cpu_hotplug_enable(void)
{
cpu_maps_update_begin();
WARN_ON(--cpu_hotplug_disabled < 0);
__cpu_hotplug_enable();
cpu_maps_update_done();
}
EXPORT_SYMBOL_GPL(cpu_hotplug_enable);
@ -631,7 +638,7 @@ void enable_nonboot_cpus(void)
/* Allow everyone to use the CPU hotplug again */
cpu_maps_update_begin();
WARN_ON(--cpu_hotplug_disabled < 0);
__cpu_hotplug_enable();
if (cpumask_empty(frozen_cpus))
goto out;