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kernel/printk: Block cpuhotplug callback when tasks are frozen

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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;
}