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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: 90b14889d2 ("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>
This commit is contained in:
Thomas Gleixner 2016-11-17 17:31:55 +01:00
parent 0e285d36bd
commit f97960fbdd
1 changed files with 4 additions and 2 deletions
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6
kernel/printk/printk.c
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@ -2194,8 +2194,10 @@ void resume_console(void)
*/
static int console_cpu_notify(unsigned int cpu)
{
console_lock();
console_unlock();
if (!cpuhp_tasks_frozen) {
console_lock();
console_unlock();
}
return 0;
}