2.6.18-rt1

Ingo Molnar · External Since: May 15, 2006 Posts: 3111

I'm pleased to announce the 2.6.18-rt1 tree, which can be downloaded
from the usual place:

http://redhat.com/~mingo/realtime-preempt/

This port to the 2.6.18 codebase was very complex (given that 5 major
features moved from -rt into 2.6.18: rtmutex, pi-futex, genirq, gtod and
lockdep), so it took quite some time to finish, but in exchange it
includes nice new features and also lots of bugfixes.

In particular, a nasty softirq performance bug has been fixed, which
caused the "5x slowdown under TCP" bug reported to lkml - those TCP
performance figures are now on par with vanilla performance.

The biggest new features are:

- Dynticks (a tickless kernel). This is a new feature we implemented
ontop of hrtimers for the -hrt patchqueue and now we merged it to -rt
too. There's a new config option: CONFIG_NO_HZ, which if enabled,
produces a system with fewer timer interrupts. Currently i686 and
x86_64 are tested, but in general a hrtimers-ready platform needs
minimal changes to support dynticks too. (from Thomas Gleixner and
me, the x86_64 port is from Arjan van de Ven)

- Timer expiry statistics feature from Thomas Gleixner:
CONFIG_TIMER_STATS. Enable/disable via "echo 1[0] > /proc/tstats",
display via "cat /proc/stats".

This kernel feature tracks the starting site (and expiry function) of
expired timers (both timer_list timers and hrtimers), and the number
of times they expired. This is a nice tool for those who'd like to
minimize the amount of timer ticks on their battery-based systems.
Sample output:

Timerstats sample period: 3.888770 s
12, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
15, 1 swapper hcd_submit_urb (rh_timer_func)
4, 959 kedac schedule_timeout (process_timeout)
1, 0 swapper page_writeback_init (wb_timer_fn)
28, 0 swapper hrtimer_stop_sched_tick (hrtimer_sched_tick)
22, 2948 IRQ 4 tty_flip_buffer_push (delayed_work_timer_fn)
3, 3100 bash schedule_timeout (process_timeout)
1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
1, 1 swapper queue_delayed_work_on (delayed_work_timer_fn)
1, 1 swapper neigh_table_init_no_netlink (neigh_periodic_timer)
1, 2292 ip __netdev_watchdog_up (dev_watchdog)
1, 23 events/1 do_cache_clean (delayed_work_timer_fn)
90 total events, 30.0 events/sec

- There's also a new runtime-configurable kernel option under
/proc/sys/kernel/timeout_granularity that allows the coarser expiry
of timer_list timers, and hence better batching of timer expiry.
(hrtimers are not affected) The value of this option gives a
'multiplier' to the standard HZ granularity.

- Lock validator ported to -rt: it now checks all the sleeping lock
variants in -rt too. This helps us catch not only deadlocks but also
raw-lock candidates, sooner than before.

- The latest High Resolution Timers queue from Thomas Gleixner with
initial support for ARM and PPC. (Kevin Hilman, Deepak Saksena,
Sergei Shtylyov)

- The latest GTOD (Generic Time Of Day) queue from John Stultz,
including NTP cleanups from Roman Zippel.

- The latest genirq queue: more irq-chip-ization of i686 and x86_64,
MSI cleanups from Eric W. Biederman et al.

- The latest preemptible-RCU queue from Paul E McKenney and Dipankar
Sarma.

- (assorted fixes and improvements.)

Right now i686 and x86_64 are boot-tested, and ARM is compile-tested.
The other architectures likely wont even build yet. This being the first
2.6.18 based release of -rt, some tester caution is called for.

to build a 2.6.18-rt1 tree, the following patches should be applied:

http://kernel.org/pub/linux/kernel/v2.6/linux-2.6.18.tar.bz2
http://redhat.com/~mingo/realtime-preempt/patch-2.6.18-rt1

as usual, bugreports, fixes and suggestions are welcome,

Ingo
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Ingo Molnar · External Since: May 15, 2006 Posts: 3111

* Gene Heskett <gene.heskett.DeleteThis@verizon.net> wrote:

> LD .tmp_vmlinux1
> kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
> : undefined reference to `hrtimer_update_timer_prio'
> make: *** [.tmp_vmlinux1] Error 1

yeah, the !hrt build broke in the last minute, i've uploaded -rt2 with
the fix.

Ingo
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Gene Heskett · External Since: May 10, 2005 Posts: 109

On Wednesday 20 September 2006 12:58, Ingo Molnar wrote:
>* Gene Heskett <gene.heskett.DeleteThis@verizon.net> wrote:
>> LD .tmp_vmlinux1
>>
>> kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
>> : undefined reference to `hrtimer_update_timer_prio'
>>
>> make: *** [.tmp_vmlinux1] Error 1
>
>yeah, the !hrt build broke in the last minute, i've uploaded -rt2 with
>the fix.
>
> Ingo
Link?

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
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Paul E. McKenney · External Since: Jun 08, 2006 Posts: 109

On Wed, Sep 20, 2006 at 10:00:38AM -0700, Daniel Walker wrote:
> On Wed, 2006-09-20 at 12:50 -0400, Gene Heskett wrote:
>
> > LD .tmp_vmlinux1
> > kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
> > : undefined reference to `hrtimer_update_timer_prio'
> > make: *** [.tmp_vmlinux1] Error 1
> >
> > about half way thru the normal time. config attached. I don't think hires
> > timers are enabled.
> >
> > Comments?
> >
>
> Fix attached.
>
> Daniel

Compiles for me with this patch. Will try it out on a couple of machines.

Thanx, Paul
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Daniel Walker · External Since: May 14, 2006 Posts: 391

On Wed, 2006-09-20 at 10:38 -0700, Paul E. McKenney wrote:
> On Wed, Sep 20, 2006 at 10:00:38AM -0700, Daniel Walker wrote:
> > On Wed, 2006-09-20 at 12:50 -0400, Gene Heskett wrote:
> >
> > > LD .tmp_vmlinux1
> > > kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
> > > : undefined reference to `hrtimer_update_timer_prio'
> > > make: *** [.tmp_vmlinux1] Error 1
> > >
> > > about half way thru the normal time. config attached. I don't think hires
> > > timers are enabled.
> > >
> > > Comments?
> > >
> >
> > Fix attached.
> >
> > Daniel
>
> Compiles for me with this patch. Will try it out on a couple of machines.
>

Ingo actually updated with a similar fix , in

http://people.redhat.com/~mingo/realtime-preempt/patch-2.6.18-rt2

Daniel

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Gene Heskett · External Since: May 10, 2005 Posts: 109

On Wednesday 20 September 2006 13:41, Daniel Walker wrote:

[...]

>Ingo actually updated with a similar fix , in
>
>http://people.redhat.com/~mingo/realtime-preempt/patch-2.6.18-rt2
>
>Daniel

And that built, but I haven't rebooted yet, thats next.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
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Paul E. McKenney · External Since: Jun 08, 2006 Posts: 109

On Wed, Sep 20, 2006 at 10:41:58AM -0700, Daniel Walker wrote:
> On Wed, 2006-09-20 at 10:38 -0700, Paul E. McKenney wrote:
> > On Wed, Sep 20, 2006 at 10:00:38AM -0700, Daniel Walker wrote:
> > > On Wed, 2006-09-20 at 12:50 -0400, Gene Heskett wrote:
> > >
> > > > LD .tmp_vmlinux1
> > > > kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
> > > > : undefined reference to `hrtimer_update_timer_prio'
> > > > make: *** [.tmp_vmlinux1] Error 1
> > > >
> > > > about half way thru the normal time. config attached. I don't think hires
> > > > timers are enabled.
> > > >
> > > > Comments?
> > > >
> > >
> > > Fix attached.
> > >
> > > Daniel
> >
> > Compiles for me with this patch. Will try it out on a couple of machines.
> >
>
> Ingo actually updated with a similar fix , in
>
> http://people.redhat.com/~mingo/realtime-preempt/patch-2.6.18-rt2

OK, using that instead.

I get the following at startup, which probably means that I need to use
some machine other than a NUMA-Q. Trying a different machine...

Thanx, Paul

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000
printing eip:
c01151ff
*pde = 34d21001
*pte = 00000000
stopped custom tracer.
Oops: 0000 [#1]
PREEMPT SMP
Modules linked in:
CPU: 2
EIP: 0060:[<c01151ff>] Not tainted VLI
EFLAGS: 00010246 (2.6.18-rt2-autokern1 #1)
EIP is at __wake_up_common+0x10/0x55
eax: 00000000 ebx: 00000001 ecx: c113629c edx: 00000000
esi: c113629c edi: c113629c ebp: dff25f34 esp: dff25f24
ds: 007b es: 007b ss: 0068 preempt: 00000001
Process softirq-timer/2 (pid: 27, ti=dff24000 task=dff20e30 task.ti=dff24000)
Stack: 00000000 00000000 c113629c 00000001 dff25f60 c0115267 c113629c 00000006
00000001 00000001 00000000 00000006 00000007 dffd5e40 c1136270 c1136240
c012ecf6 00000000 00000001 c11360e4 00000001 00000000 dff12000 c043b2c0
Call Trace:
[<c0115267>] __wake_up+0x23/0x52
[<c012ecf6>] hrtimer_run_queues+0xf6/0x10f
[<c0123db3>] run_timer_softirq+0x13b/0x31b
[<c011fba0>] ksoftirqd+0xff/0x194
[<c011faa1>] ksoftirqd+0x0/0x194
[<c012beee>] kthread+0x82/0xa7
[<c012be6c>] kthread+0x0/0xa7
[<c0101031>] kernel_thread_helper+0x5/0xb
---------------------------
| preempt count: 00000001 ]
| 1-level deep critical section nesting:
----------------------------------------
... [<c02fd493>] .... __spin_lock_irqsave+0xe/0x35
......[<00000000>] .. ( <= _stext+0x3feffd68/0x41)

Code: 45 14 00 00 00 00 8b 45 08 83 ca 01 89 55 0c 8b 40 04 89 45 08 5d e9 62 e2 ff ff 55 89 e5 57 56 53 50 8b 7d 08 8b 5d 10 8b 57 20 <8b> 02 89 45 f0 8d 47 20 39 c2 74 31 8b 72 f4 8d 42 f4 ff 75 18
EIP: [<c01151ff>] __wake_up_common+0x10/0x55 SS:ESP 0068:dff25f24
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Daniel Walker · External Since: May 14, 2006 Posts: 391

On Wed, 2006-09-20 at 11:25 -0700, Paul E. McKenney wrote:

> OK, using that instead.
>
> I get the following at startup, which probably means that I need to use
> some machine other than a NUMA-Q. Trying a different machine...
>
> Thanx, Paul
>
> BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000
> printing eip:
> c01151ff
> *pde = 34d21001
> *pte = 00000000
> stopped custom tracer.
> Oops: 0000 [#1]
> PREEMPT SMP
> Modules linked in:
> CPU: 2
> EIP: 0060:[<c01151ff>] Not tainted VLI
> EFLAGS: 00010246 (2.6.18-rt2-autokern1 #1)
> EIP is at __wake_up_common+0x10/0x55

I get this too, it happens when HRT is off.. If you turn HRT on it will
boot .. I haven't found a fix for it, but I imagine Thomas will find it
soon.

Daniel

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Gene Heskett · External Since: May 10, 2005 Posts: 109

On Wednesday 20 September 2006 12:58, Ingo Molnar wrote:
>* Gene Heskett <gene.heskett RemoveThis @verizon.net> wrote:
>> LD .tmp_vmlinux1
>>
>> kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
>> : undefined reference to `hrtimer_update_timer_prio'
>>
>> make: *** [.tmp_vmlinux1] Error 1
>
>yeah, the !hrt build broke in the last minute, i've uploaded -rt2 with
>the fix.
>
And that one does an Opps during boot & freezes. The first line says
something about being unable to handle a dereference of $00000000, and
goes on from there. Its about 2 screens full, so I'd have to take a pix
to get any more really accurate data.

I guess we could say the "can an old fart build it" test failed Smile

> Ingo
>-
>To unsubscribe from this list: send the line "unsubscribe linux-kernel"
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>Please read the FAQ at http://www.tux.org/lkml/

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
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Thomas Gleixner · External Since: May 14, 2006 Posts: 943

On Wed, 2006-09-20 at 14:36 -0400, Gene Heskett wrote:
> That looks like the chorus of the song I saw when it crashed on boot,
> pretty darned close to identical.

I can reproduce it. It happens when CONFIG_HIGH_RES_TIMERS is off.
Looking into it right now.

tglx

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Gene Heskett · External Since: May 10, 2005 Posts: 109

On Wednesday 20 September 2006 14:25, Paul E. McKenney wrote:
>On Wed, Sep 20, 2006 at 10:41:58AM -0700, Daniel Walker wrote:
>> On Wed, 2006-09-20 at 10:38 -0700, Paul E. McKenney wrote:
>> > On Wed, Sep 20, 2006 at 10:00:38AM -0700, Daniel Walker wrote:
>> > > On Wed, 2006-09-20 at 12:50 -0400, Gene Heskett wrote:
>> > > > LD .tmp_vmlinux1
>> > > >
>> > > > kernel/built-in.o(.text+0x16f25): In function `hrtimer_start':
>> > > > : undefined reference to `hrtimer_update_timer_prio'
>> > > >
>> > > > make: *** [.tmp_vmlinux1] Error 1
>> > > >
>> > > > about half way thru the normal time. config attached. I don't
>> > > > think hires timers are enabled.
>> > > >
>> > > > Comments?
>> > >
>> > > Fix attached.
>> > >
>> > > Daniel
>> >
>> > Compiles for me with this patch. Will try it out on a couple of
>> > machines.
>>
>> Ingo actually updated with a similar fix , in
>>
>> http://people.redhat.com/~mingo/realtime-preempt/patch-2.6.18-rt2
>
>OK, using that instead.
>
>I get the following at startup, which probably means that I need to use
>some machine other than a NUMA-Q. Trying a different machine...
>
> Thanx, Paul
>
>BUG: unable to handle kernel NULL pointer dereference at virtual address
> 00000000 printing eip:
>c01151ff
>*pde = 34d21001
>*pte = 00000000
>stopped custom tracer.
>Oops: 0000 [#1]
>PREEMPT SMP
>Modules linked in:
>CPU: 2
>EIP: 0060:[<c01151ff>] Not tainted VLI
>EFLAGS: 00010246 (2.6.18-rt2-autokern1 #1)
>EIP is at __wake_up_common+0x10/0x55
>eax: 00000000 ebx: 00000001 ecx: c113629c edx: 00000000
>esi: c113629c edi: c113629c ebp: dff25f34 esp: dff25f24
>ds: 007b es: 007b ss: 0068 preempt: 00000001
>Process softirq-timer/2 (pid: 27, ti=dff24000 task=dff20e30
> task.ti=dff24000) Stack: 00000000 00000000 c113629c 00000001 dff25f60
> c0115267 c113629c 00000006 00000001 00000001 00000000 00000006 00000007
> dffd5e40 c1136270 c1136240 c012ecf6 00000000 00000001 c11360e4 00000001
> 00000000 dff12000 c043b2c0 Call Trace:
> [<c0115267>] __wake_up+0x23/0x52
> [<c012ecf6>] hrtimer_run_queues+0xf6/0x10f
> [<c0123db3>] run_timer_softirq+0x13b/0x31b
> [<c011fba0>] ksoftirqd+0xff/0x194
> [<c011faa1>] ksoftirqd+0x0/0x194
> [<c012beee>] kthread+0x82/0xa7
> [<c012be6c>] kthread+0x0/0xa7
> [<c0101031>] kernel_thread_helper+0x5/0xb
>---------------------------
>
>| preempt count: 00000001 ]
>| 1-level deep critical section nesting:
>
>----------------------------------------
>.. [<c02fd493>] .... __spin_lock_irqsave+0xe/0x35
>.....[<00000000>] .. ( <= _stext+0x3feffd68/0x41)
>
>Code: 45 14 00 00 00 00 8b 45 08 83 ca 01 89 55 0c 8b 40 04 89 45 08 5d
> e9 62 e2 ff ff 55 89 e5 57 56 53 50 8b 7d 08 8b 5d 10 8b 57 20 <8b> 02
> 89 45 f0 8d 47 20 39 c2 74 31 8b 72 f4 8d 42 f4 ff 75 18 EIP:
> [<c01151ff>] __wake_up_common+0x10/0x55 SS:ESP 0068:dff25f24

That looks like the chorus of the song I saw when it crashed on boot,
pretty darned close to identical.

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
-
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Thomas Gleixner · External Since: May 14, 2006 Posts: 943

On Wed, 2006-09-20 at 20:47 +0200, Thomas Gleixner wrote:
> On Wed, 2006-09-20 at 14:36 -0400, Gene Heskett wrote:
> > That looks like the chorus of the song I saw when it crashed on boot,
> > pretty darned close to identical.
>
> I can reproduce it. It happens when CONFIG_HIGH_RES_TIMERS is off.
> Looking into it right now.

Fix below.

tglx

Index: linux-2.6.18/kernel/hrtimer.c
===================================================================
--- linux-2.6.18.orig/kernel/hrtimer.c 2006-09-20 19:10:05.000000000 +0200
+++ linux-2.6.18/kernel/hrtimer.c 2006-09-20 21:11:26.000000000 +0200
@@ -873,9 +873,6 @@ static inline void hrtimer_init_hres(str
set_bit(0, &base->check_clocks);
base->hres_active = 0;
hrtimer_init_base_cb_pending(base);
-#ifdef CONFIG_PREEMPT_SOFTIRQS
- init_waitqueue_head(&base->wait);
-#endif
}

static inline int hrtimer_enqueue_reprogram(struct hrtimer *timer,
@@ -1643,6 +1640,9 @@ static void __devinit init_hrtimers_cpu(
cpu_base->clock_base[i].cpu_base = cpu_base;

hrtimer_init_hres(cpu_base);
+#ifdef CONFIG_PREEMPT_SOFTIRQS
+ init_waitqueue_head(&cpu_base->wait);
+#endif
}

#ifdef CONFIG_HOTPLUG_CPU

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Mark Knecht · External Since: Feb 20, 2006 Posts: 242

On 9/20/06, Ingo Molnar <mingo.DeleteThis@elte.hu> wrote:
> I'm pleased to announce the 2.6.18-rt1 tree, which can be downloaded
> from the usual place:
>
> http://redhat.com/~mingo/realtime-preempt/
>

Hi Ingo,
I gave 2.6.18-rt2 a quick try. It compiled fine but crashed on
boot. I've no way to copy the screen. I can send along a digital photo
if the following isn't enough info.

QUESTION: Should I be able to run ati-drivers-8.28.8 with this kernel
or would I have to wait for ATI to put out a 2.6.18 compatible driver?
The current version does not emerge with 2.6.18-rt2.

CRASH INFO:

Unable to handle kernel null pointer derefernce at 0000000000000000 RIP
[< ffffffff80228ae4 >] __wake_up_common+0x24/0x68
PGD 3d6e7067 PUD 3d638067 PMD 0
Oops: 0000 [1] PREEMPT SMP
CPU
Modules linked in:
Pid: 5, comm:softirq-timer/0 Not tainted 2.6.18-rt2 #2

There is a bunch of debug stuff that follows and then finally a trace:

__wake_up
hrt_time_run_queue
run_timer_softirq
kthread
child_rip
DWARF2 unwinder stuck at child_rip

more stuff......

preempt count: 00000001
1-level deep critical nesting:

__spin_trylock

Not sure how much that will help you. Been awhile since I've sent
along crash reports. I'll have to ge a second Linux machine running to
do the console boot capture thing if you need it.

Hope this helps,
Mark
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Thomas Gleixner · External Since: May 14, 2006 Posts: 943

On Wed, 2006-09-20 at 13:56 -0500, K.R. Foley wrote:
> EIP: 0060:[<c0130ad4>] Not tainted VLI
> EFLAGS: 00010297 (2.6.17-rt8 #4)

----------------------^^^^^^^^^^^^^

Are you sure, that kernel and .config are related ?

tglx

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Ingo Molnar · External Since: May 15, 2006 Posts: 3111

* K.R. Foley <kr.DeleteThis@cybsft.com> wrote:

> Ingo Molnar wrote:
> > I'm pleased to announce the 2.6.18-rt1 tree, which can be downloaded
> > from the usual place:
> >
> > http://redhat.com/~mingo/realtime-preempt/
> >
>
> I got the following oops when trying to boot the above. Config is attached.

maybe it's not the right kernel image (2.6.17):

> EFLAGS: 00010297 (2.6.17-rt8 #4)

mixed with 2.6.18 modules?

Ingo
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Ingo Molnar · External Since: May 15, 2006 Posts: 3111

* Gene Heskett <gene.heskett.DeleteThis@verizon.net> wrote:

> That looks like the chorus of the song I saw when it crashed on boot,
> pretty darned close to identical.

ok, i've uploaded -rt3:

http://redhat.com/~mingo/realtime-preempt/

this should have this one fixed.

Ingo
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Paul E. McKenney · External Since: Jun 08, 2006 Posts: 109

On Wed, Sep 20, 2006 at 11:34:00AM -0700, Daniel Walker wrote:
> On Wed, 2006-09-20 at 11:25 -0700, Paul E. McKenney wrote:
> >
> > BUG: unable to handle kernel NULL pointer dereference at virtual address 00000000
> > printing eip:
> > c01151ff
> > *pde = 34d21001
> > *pte = 00000000
> > stopped custom tracer.
> > Oops: 0000 [#1]
> > PREEMPT SMP
> > Modules linked in:
> > CPU: 2
> > EIP: 0060:[<c01151ff>] Not tainted VLI
> > EFLAGS: 00010246 (2.6.18-rt2-autokern1 #1)
> > EIP is at __wake_up_common+0x10/0x55
>
> I get this too, it happens when HRT is off.. If you turn HRT on it will
> boot .. I haven't found a fix for it, but I imagine Thomas will find it
> soon.

Enabling HRT works for me too -- thanks to you and Thomas for the hint!

Thanx, Paul
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Gene Heskett · External Since: May 10, 2005 Posts: 109

On Wednesday 20 September 2006 14:34, Daniel Walker wrote:
>On Wed, 2006-09-20 at 11:25 -0700, Paul E. McKenney wrote:
>> OK, using that instead.
>>
>> I get the following at startup, which probably means that I need to use
>> some machine other than a NUMA-Q. Trying a different machine...
>>
>> Thanx, Paul
>>
>> BUG: unable to handle kernel NULL pointer dereference at virtual
>> address 00000000 printing eip:
>> c01151ff
>> *pde = 34d21001
>> *pte = 00000000
>> stopped custom tracer.
>> Oops: 0000 [#1]
>> PREEMPT SMP
>> Modules linked in:
>> CPU: 2
>> EIP: 0060:[<c01151ff>] Not tainted VLI
>> EFLAGS: 00010246 (2.6.18-rt2-autokern1 #1)
>> EIP is at __wake_up_common+0x10/0x55
>
>I get this too, it happens when HRT is off.. If you turn HRT on it will
>boot .. I haven't found a fix for it, but I imagine Thomas will find it
>soon.
>
>Daniel

I'm re-building with HRT on now, but I just noticed another side effect of
2.6.18. I have an led sniffer plugged into the pl2302 usb<->serial
adaptor laying where I can see it, and all leds are red, as if the
interface has not been inited properly. And I don't see it being
initialized in the dmesg. I thought the default was to build it. Yup,
pl2303.ko is present in the /lib/modules trees all across the board.

Any ideas on this one folks?

--
Cheers, Gene
"There are four boxes to be used in defense of liberty:
soap, ballot, jury, and ammo. Please use in that order."
-Ed Howdershelt (Author)
Yahoo.com and AOL/TW attorneys please note, additions to the above
message by Gene Heskett are:
Copyright 2006 by Maurice Eugene Heskett, all rights reserved.
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Daniel Walker · External Since: May 14, 2006 Posts: 391

On Wed, 2006-09-20 at 21:46 +0200, Ingo Molnar wrote:
> * Gene Heskett <gene.heskett DeleteThis @verizon.net> wrote:
>
> > That looks like the chorus of the song I saw when it crashed on boot,
> > pretty darned close to identical.
>
> ok, i've uploaded -rt3:
>
> http://redhat.com/~mingo/realtime-preempt/
>
> this should have this one fixed.
>
> Ingo

What about the !PREEMPT_RT case.. It still wouldn't disable interrupts
in the below..

- local_irq_save(flags);
if (up->port.sysrq) {
/* serial8250_handle_port() already took the lock */
locked = 0;
} else if (oops_in_progress) {
- locked = spin_trylock(&up->port.lock);
+ locked = spin_trylock_irqsave(&up->port.lock, flags);
} else
- spin_lock(&up->port.lock);
+ spin_lock_irqsave(&up->port.lock, flags);

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Ingo Molnar · External Since: May 15, 2006 Posts: 3111

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

> What about the !PREEMPT_RT case.. It still wouldn't disable interrupts
> in the below..
>
> - local_irq_save(flags);
> if (up->port.sysrq) {
> /* serial8250_handle_port() already took the lock */
> locked = 0;
> } else if (oops_in_progress) {
> - locked = spin_trylock(&up->port.lock);
> + locked = spin_trylock_irqsave(&up->port.lock, flags);
> } else
> - spin_lock(&up->port.lock);
> + spin_lock_irqsave(&up->port.lock, flags);

_irqsave disables interrupts, always did.

Ingo
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