linux-kernel - [PATCH] Fix scheduling-while-atomic problem in console_cpu

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Date:	Mon, 15 Oct 2012 17:31:28 -0700
From:	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
To:	linux-kernel@...r.kernel.org
Cc:	cernekee@...il.com, torbenh@....de, torvalds@...ux-foundation.org,
	tglx@...utronix.de, srivatsa.bhat@...ux.vnet.ibm.com
Subject: [PATCH] Fix scheduling-while-atomic problem in console_cpu_notify()

The console_cpu_notify( function runs with interrupts disabled in
the CPU_DEAD case.  It therefore cannot block, for example, as will
happen when it calls console_lock().  Therefore, remove the CPU_DEAD
leg of the switch statement to avoid this problem.

Signed-off-by: Paul E. McKenney <paul.mckenney@...aro.org>

diff --git a/kernel/printk.c b/kernel/printk.c
index 66a2ea3..8e23a14 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1889,7 +1889,6 @@ static int __cpuinit console_cpu_notify(struct notifier_block *self,
 {
 	switch (action) {
 	case CPU_ONLINE:
-	case CPU_DEAD:
 	case CPU_DYING:
 	case CPU_DOWN_FAILED:
 	case CPU_UP_CANCELED:

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