[3.5.y.z extended stable] Patch "printk: Fix scheduling-while-atomic problem in console_cpu_notify()" has been added to staging queue

[Luis Henriques]

This is a note to let you know that I have just added a patch titled

    printk: Fix scheduling-while-atomic problem in console_cpu_notify()

to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.5.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Luis

------

>From fe91c17c98fa57c5c3a0831abd4f61d81c4d2209 Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck at linux.vnet.ibm.com>
Date: Mon, 15 Oct 2012 21:35:59 -0700
Subject: printk: Fix scheduling-while-atomic problem in console_cpu_notify()

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