[PATCH -rt] temporary WARN_ON removal

[PATCH -rt] temporary WARN_ON removal

[Daniel Walker]

These two WARN_ON calls send my system into a boot hang. They trigger
over and over , some examples below.

[   58.438501] WARNING: at kernel/sched.c:3785 schedule()
[   58.443444]  [<c039b224>] schedule+0x74/0x110
[   58.447772]  [<c039a67f>] rest_init+0x4f/0x60
[   58.452092]  [<c0490a8f>] start_kernel+0x2cf/0x310
[   58.456848]  [<c0490210>] unknown_bootoption+0x0/0x250
[   58.461951]  =======================
[   58.465496] WARNING: at kernel/sched.c:3683 schedule_debug()
[   58.471118]  [<c039ae0c>] __schedule+0x4cc/0x760
[   58.475702]  [<c010511a>] print_trace_address+0x1a/0x30
[   58.480893]  [<c0129a2b>] printk+0x1b/0x20
[   58.484957]  [<c01051f8>] show_trace_log_lvl+0x28/0x30
[   58.490060]  [<c039b1de>] schedule+0x2e/0x110
[   58.494385]  [<c039a67f>] rest_init+0x4f/0x60
[   58.498709]  [<c0490a8f>] start_kernel+0x2cf/0x310
[   58.503465]  [<c0490210>] unknown_bootoption+0x0/0x250
[   58.508569]  =======================

On closer inspection I'm not sure they are correctly placed. They could
trigger or not depending on when/if certain threads run.

Here is a patch to comment them out. This should go into the
preempt-realtime-sched.patch 

Signed-Off-By: Daniel Walker <dwalker@mvista.com>

Index: linux-2.6.22.1/kernel/sched.c
===================================================================
--- linux-2.6.22.1.orig/kernel/sched.c	2007-07-22 17:18:38.000000000 +0000
+++ linux-2.6.22.1/kernel/sched.c	2007-07-22 17:17:48.000000000 +0000
@@ -3680,7 +3680,7 @@ static noinline void __schedule_bug(stru
  */
 static inline void schedule_debug(struct task_struct *prev)
 {
-	WARN_ON(system_state == SYSTEM_BOOTING);
+	//WARN_ON(system_state == SYSTEM_BOOTING);
 
 	/*
 	 * Test if we are atomic.  Since do_exit() needs to call into
@@ -3782,7 +3782,7 @@ asmlinkage void __sched __schedule(void)
  */
 asmlinkage void __sched schedule(void)
 {
-	WARN_ON(system_state == SYSTEM_BOOTING);
+	//WARN_ON(system_state == SYSTEM_BOOTING);
 	/*
 	 * Test if we have interrupts disabled.
 	 */

Re: [PATCH -rt] temporary WARN_ON removal

[Daniel Walker]

On Mon, 2007-07-23 at 21:55 +0200, Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> > These two WARN_ON calls send my system into a boot hang. They trigger 
> > over and over , some examples below.
> 
> hm, could you try to figure out why they trigger on your box and not on 
> anyone else's box? By disabling them we might be papering over a 
> potential problem.
> 

Try running with !PREEMPT_RT , that's the only time that I see those
message .. That's also why I thought it was related to timing ..

Daniel

Re: [PATCH -rt] temporary WARN_ON removal

[Ingo Molnar]

* Daniel Walker <dwalker@mvista.com> wrote:

> These two WARN_ON calls send my system into a boot hang. They trigger 
> over and over , some examples below.

hm, could you try to figure out why they trigger on your box and not on 
anyone else's box? By disabling them we might be papering over a 
potential problem.

	Ingo

Re: [PATCH -rt] temporary WARN_ON removal

[Daniel Walker]

On Mon, 2007-07-23 at 21:55 +0200, Ingo Molnar wrote:
> * Daniel Walker <dwalker@mvista.com> wrote:
> 
> > These two WARN_ON calls send my system into a boot hang. They trigger 
> > over and over , some examples below.
> 
> hm, could you try to figure out why they trigger on your box and not on 
> anyone else's box? By disabling them we might be papering over a 
> potential problem.

This patch can be ignored .. I must have mistakenly though I had the
series fully applied .. Turned out to be a bisect issue .. The WARN_ONs
are added before the SYSTEM_BOOTING_SCHEDULER_OK changes.. So naturally
you get these warnings .. The change in my tree resolved this ..

Daniel