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Subject[PATCH] cpu/hotplug: handle unbalanced hotplug enable/disable
Date
Currently it just print a warning message but did not
reset cpu_hotplug_disabled when the enable/disable is
unbalanced. The unbalanced enable/disable will lead
the cpu hotplug work abnormally.

Reset it to 0 when an unablanced enable detected.

Signed-off-by: Lianwei Wang <lianwei.wang@gmail.com>
---
kernel/cpu.c | 21 +++++++++++++++++----
1 file changed, 17 insertions(+), 4 deletions(-)

diff --git a/kernel/cpu.c b/kernel/cpu.c
index 6ea42e8da861..fef6caed77a3 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -243,6 +243,19 @@ void cpu_hotplug_done(void)
cpuhp_lock_release();
}

+static void _cpu_hotplug_disable(void)
+{
+ cpu_hotplug_disabled++;
+}
+
+static void _cpu_hotplug_enable(void)
+{
+ if (--cpu_hotplug_disabled < 0) {
+ WARN(1, "unbalanced hotplug enable %d\n", cpu_hotplug_disabled);
+ cpu_hotplug_disabled = 0;
+ }
+}
+
/*
* Wait for currently running CPU hotplug operations to complete (if any) and
* disable future CPU hotplug (from sysfs). The 'cpu_add_remove_lock' protects
@@ -253,7 +266,7 @@ void cpu_hotplug_done(void)
void cpu_hotplug_disable(void)
{
cpu_maps_update_begin();
- cpu_hotplug_disabled++;
+ _cpu_hotplug_disable();
cpu_maps_update_done();
}
EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
@@ -261,7 +274,7 @@ EXPORT_SYMBOL_GPL(cpu_hotplug_disable);
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);
@@ -1053,7 +1066,7 @@ int disable_nonboot_cpus(void)
* this even in case of failure as all disable_nonboot_cpus() users are
* supposed to do enable_nonboot_cpus() on the failure path.
*/
- cpu_hotplug_disabled++;
+ _cpu_hotplug_disable();

cpu_maps_update_done();
return error;
@@ -1073,7 +1086,7 @@ 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;

--
1.9.1
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