[PATCH 3.5 27/60] printk: Fix scheduling-while-atomic problem in console_cpu_notify()

[Luis Henriques]

3.5.7.31 -stable review patch.  If anyone has any objections, please let me know.

------------------

From: "Paul E. McKenney" <paulmck at linux.vnet.ibm.com>

commit 85eae82a0855d49852b87deac8653e4ebc8b291f upstream.

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

Signed-off-by: Paul E. McKenney <paulmck at linux.vnet.ibm.com>
Reviewed-by: Srivatsa S. Bhat <srivatsa.bhat at linux.vnet.ibm.com>
Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
Cc: Guillaume Morin <guillaume at morinfr.org>
Signed-off-by: Luis Henriques <luis.henriques at canonical.com>
---
 kernel/printk.c | 1 -
 1 file changed, 1 deletion(-)

diff --git a/kernel/printk.c b/kernel/printk.c
index e959512..0d430b1 100644
--- a/kernel/printk.c
+++ b/kernel/printk.c
@@ -1827,7 +1827,6 @@ 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:
 		console_lock();
-- 
1.9.0