[PATCH] printk: Fixup lockdep annotation in console_suspend()

[Jan Kara]

Although console_suspend() releases console_sem, it doesn't tell lockdep
about it. That results in the lockdep warning about circular locking
when doing the following:
  enter suspend ->  resume ->  plug-out CPUx (echo 0 > cpux/online)

Fix the problem by telling lockdep we actually released the semaphore in
console_suspend() and acquired it again in console_resume().

Signed-off-by: Jan Kara <jack@xxxxxxx>
---
 kernel/printk/printk.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 4dae9cbe9259..e6ada322782b 100644
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -1880,6 +1880,7 @@ void suspend_console(void)
 	console_lock();
 	console_suspended = 1;
 	up(&console_sem);
+	mutex_release(&console_lock_dep_map, 1, _RET_IP_);
 }
 
 void resume_console(void)
@@ -1887,6 +1888,7 @@ void resume_console(void)
 	if (!console_suspend_enabled)
 		return;
 	down(&console_sem);
+	mutex_acquire(&console_lock_dep_map, 0, 0, _RET_IP_);
 	console_suspended = 0;
 	console_unlock();
 }
-- 
1.8.1.4

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