Commit f97960fb authored Nov 17, 2016 by Thomas Gleixner

kernel/printk: Block cpuhotplug callback when tasks are frozen



The recent conversion of the console hotplug notifier to the state machine
missed the fact, that the notifier only operated on the non frozen
transitions. As a consequence the console_lock/unlock() pair is also
invoked during suspend, which results in a lockdep warning.

Restore the previous state by making the lock/unlock conditional on
!tasks_frozen.

Fixes: 90b14889 ("kernel/printk: Convert to hotplug state machine")
Reported-and-tested-by: Borislav Petkov <bp@alien8.de>
Link: http://lkml.kernel.org/r/alpine.DEB.2.20.1611171729320.3645@nanos


Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

parent 0e285d36

kernel/printk/printk.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -2194,8 +2194,10 @@ void resume_console(void)
		*/
		static int console_cpu_notify(unsigned int cpu)
		{
		if (!cpuhp_tasks_frozen) {
		console_lock();
		console_unlock();
		}
		return 0;
		}

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