If a custom CPU target is specified and that one is not available _or_
can't be interrupted then leave to userland without dropping a lock as
notice by lockdep:
|echo 133 > /sys/devices/system/cpu/cpu7/hotplug/target
| ================================================
| [ BUG: lock held when returning to user space! ]
| ------------------------------------------------
| bash/503 is leaving the kernel with locks still held!
| 1 lock held by bash/503:
| #0: (device_hotplug_lock){+.+...}, at: [<ffffffff815b5650>]
lock_device_hotplug_sysfs+0x10/0x40
So release the lock then.
Fixes: 757c989b9994 ("cpu/hotplug: Make target state writeable")
Cc: sta...@vger.kernel.org
Signed-off-by: Sebastian Andrzej Siewior <bige...@linutronix.de>
---
kernel/cpu.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c
index 7435ffc6163b..912621eb2286 100644
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -1627,13 +1627,13 @@ static ssize_t write_cpuhp_target(struct device *dev,
ret = !sp->name || sp->cant_stop ? -EINVAL : 0;
mutex_unlock(&cpuhp_state_mutex);
if (ret)
- return ret;
+ goto out;
if (st->state < target)
ret = do_cpu_up(dev->id, target);
else
ret = do_cpu_down(dev->id, target);
-
+out:
unlock_device_hotplug();
return ret ? ret : count;
}
--
2.11.0
