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Date: Thu, 2 May 2013 15:58:29 +0200 (CEST)
From: Thomas Gleixner <tglx@linutronix.de>
To: Markus Trippelsdorf <markus@trippelsdorf.de>
cc: linux-kernel@vger.kernel.org
Subject: Re: WARNING: at kernel/cpu/idle.c:96
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On Thu, 2 May 2013, Markus Trippelsdorf wrote:
> On 2013.05.02 at 12:43 +0200, Thomas Gleixner wrote:
> > On Tue, 30 Apr 2013, Markus Trippelsdorf wrote:
> > 
> > > Just booted todays git tree and got the following warning:
> > > 
> > > ------------[ cut here ]------------
> > > WARNING: at kernel/cpu/idle.c:96 cpu_startup_entry+0x14d/0x160()
> > > Hardware name: System Product Name
> > > Pid: 0, comm: swapper/2 Not tainted 3.9.0-03462-gab86e97-dirty #424
> > > Call Trace:
> > > smpboot: Booting Node   0, Processors  #1 #2
> > >  [<ffffffff8105b7c0>] ? warn_slowpath_common+0x60/0xa0
> > >  [<ffffffff8108c26d>] ? cpu_startup_entry+0x14d/0x160
> > > ---[ end trace 40a24a5550891913 ]---
> > 
> > Fix below.
> 
> Unfortunately the fix doesn't work:

Moo. I missed amd_e400_idle() returning early w/o enabling interrupts.

Full patch below.

Thanks,

	tglx

diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 607af0d..0526a96 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -312,6 +312,8 @@ void arch_cpu_idle(void)
 {
 	if (cpuidle_idle_call())
 		x86_idle();
+	else
+		local_irq_enable();
 }
 
 /*
@@ -368,8 +370,10 @@ void amd_e400_remove_cpu(int cpu)
  */
 static void amd_e400_idle(void)
 {
-	if (need_resched())
+	if (need_resched()) {
+		local_irq_enable();
 		return;
+	}
 
 	if (!amd_e400_c1e_detected) {
 		u32 lo, hi;