[REGRESSION] 2.6.24-rc1 fails to boot on a 486

[REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Mikael Pettersson]

My old 486 fails to boot with the 2.6.24-rc1 kernel.
Grub loads it, 4 lines of text appear but not the kernel's
"Linux version <blah> greet", and the machine reboots.
Double-checked with a serial console: nothing appears
before it reboots.

All 2.6 kernels up to 2.6.23 worked fine on this machine.

Config is at http://user.it.uu.se/~mikpe/linux/tmp/486-config-2.6.24-rc1.
The kernel is unpatched 2.6.24-rc1 compiled with gcc-4.2.2.

/Mikael

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[H. Peter Anvin]

Mikael Pettersson wrote:
> My old 486 fails to boot with the 2.6.24-rc1 kernel.
> Grub loads it, 4 lines of text appear but not the kernel's
> "Linux version <blah> greet", and the machine reboots.
> Double-checked with a serial console: nothing appears
> before it reboots.

What four lines of text?

	-hpa

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[H. Peter Anvin]

Mikael Pettersson wrote:
> My old 486 fails to boot with the 2.6.24-rc1 kernel.
> Grub loads it, 4 lines of text appear but not the kernel's
> "Linux version <blah> greet", and the machine reboots.
> Double-checked with a serial console: nothing appears
> before it reboots.
> 
> All 2.6 kernels up to 2.6.23 worked fine on this machine.
> 
> Config is at http://user.it.uu.se/~mikpe/linux/tmp/486-config-2.6.24-rc1.
> The kernel is unpatched 2.6.24-rc1 compiled with gcc-4.2.2.
> 

Any chance you could bisect this problem?

	-hpa

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Mikael Pettersson]

On Sun, 28 Oct 2007 21:33:02 -0700, H. Peter Anvin wrote:
> Mikael Pettersson wrote:
> > My old 486 fails to boot with the 2.6.24-rc1 kernel.
> > Grub loads it, 4 lines of text appear but not the kernel's
> > "Linux version <blah> greet", and the machine reboots.
> > Double-checked with a serial console: nothing appears
> > before it reboots.
> 
> What four lines of text?

They're impossible to capture because they're only visible
on the VGA screen for like 0.2 seconds before the machine
reboots and the screen is blanked; they don't show up on
the serial console.

They look like paths to the vmlinuz and initrd surrounded
by [ ] brackets, so I guess they come from grub.

/Mikael

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Ingo Molnar]

* Mikael Pettersson <mikpe@it.uu.se> wrote:

> On Sun, 28 Oct 2007 21:33:02 -0700, H. Peter Anvin wrote:
> > Mikael Pettersson wrote:
> > > My old 486 fails to boot with the 2.6.24-rc1 kernel.
> > > Grub loads it, 4 lines of text appear but not the kernel's
> > > "Linux version <blah> greet", and the machine reboots.
> > > Double-checked with a serial console: nothing appears
> > > before it reboots.
> > 
> > What four lines of text?
> 
> They're impossible to capture because they're only visible on the VGA 
> screen for like 0.2 seconds before the machine reboots and the screen 
> is blanked; they don't show up on the serial console.

the way i debug these is to take a digital camera and make a movie of 
the bootup, then check the movie frame for frame.

admittedly it's a pretty sick method.

	Ingo

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Gabriel C]

Mikael Pettersson wrote:
> On Sun, 28 Oct 2007 21:33:02 -0700, H. Peter Anvin wrote:
>> Mikael Pettersson wrote:
>>> My old 486 fails to boot with the 2.6.24-rc1 kernel.
>>> Grub loads it, 4 lines of text appear but not the kernel's
>>> "Linux version <blah> greet", and the machine reboots.
>>> Double-checked with a serial console: nothing appears
>>> before it reboots.
>> What four lines of text?
> 
> They're impossible to capture because they're only visible
> on the VGA screen for like 0.2 seconds before the machine
> reboots and the screen is blanked; they don't show up on
> the serial console.

Maybe try to set CONFIG_BOOT_PRINTK_DELAY and boot with boot_delay=N ?

> 
> They look like paths to the vmlinuz and initrd surrounded
> by [ ] brackets, so I guess they come from grub.
> 
> /Mikael


Regards,

Gabriel

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Thomas Gleixner]

On Mon, 29 Oct 2007, Mikael Pettersson wrote:

> On Sun, 28 Oct 2007 21:33:02 -0700, H. Peter Anvin wrote:
> > Mikael Pettersson wrote:
> > > My old 486 fails to boot with the 2.6.24-rc1 kernel.
> > > Grub loads it, 4 lines of text appear but not the kernel's
> > > "Linux version <blah> greet", and the machine reboots.
> > > Double-checked with a serial console: nothing appears
> > > before it reboots.
> > 
> > What four lines of text?
> 
> They're impossible to capture because they're only visible
> on the VGA screen for like 0.2 seconds before the machine
> reboots and the screen is blanked; they don't show up on
> the serial console.
> 
> They look like paths to the vmlinuz and initrd surrounded
> by [ ] brackets, so I guess they come from grub.

Any chance to use serial console ?

Enable CONFIG_EARLY_PRINTK and add
 
earlyprintk=serial,ttyS0,115200,keep

to the kernel command line.

Can you please provide your .config file ?

I tested on my i386 box and Linus latest git boots fine:
# uname -a
Linux museum386 2.6.24-rc1-2a397e82 #1 PREEMPT Mon Oct 29 13:39:29 CET 2007 i386 unknown
# cat /proc/cpuinfo
processor       : 0
vendor_id       : unknown
cpu family      : 3
model           : 0
model name      : 386
stepping        : unknown
fdiv_bug        : no
hlt_bug         : no
f00f_bug        : no
coma_bug        : no
fpu             : no
fpu_exception   : no
cpuid level     : -1
wp              : no
flags           :
bogomips        : 6.93
clflush size    : 32

Thanks,

	tglx

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[H. Peter Anvin]

Thomas Gleixner wrote:
>>
>> They look like paths to the vmlinuz and initrd surrounded
>> by [ ] brackets, so I guess they come from grub.
> 
> Any chance to use serial console ?
> 
> Enable CONFIG_EARLY_PRINTK and add
>  
> earlyprintk=serial,ttyS0,115200,keep
> 
> to the kernel command line.
> 
> Can you please provide your .config file ?
> 

I doubt he's getting far enough that he's actually getting early printk. 
  I could be wrong, of course.

> I tested on my i386 box and Linus latest git boots fine:
> # uname -a
> Linux museum386 2.6.24-rc1-2a397e82 #1 PREEMPT Mon Oct 29 13:39:29 CET 2007 i386 unknown
> # cat /proc/cpuinfo
> clflush size    : 32

Hm.  This probably shouldn't be displayed when clflush isn't available...

	-hpa

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Thomas Gleixner]

On Mon, 29 Oct 2007, H. Peter Anvin wrote:
> Thomas Gleixner wrote:
> > > 
> > > They look like paths to the vmlinuz and initrd surrounded
> > > by [ ] brackets, so I guess they come from grub.
> > 
> > Any chance to use serial console ?
> > 
> > Enable CONFIG_EARLY_PRINTK and add
> >  earlyprintk=serial,ttyS0,115200,keep
> > 
> > to the kernel command line.
> > 
> > Can you please provide your .config file ?
> > 
> 
> I doubt he's getting far enough that he's actually getting early printk.  I
> could be wrong, of course.
> 
> > I tested on my i386 box and Linus latest git boots fine:
> > # uname -a
> > Linux museum386 2.6.24-rc1-2a397e82 #1 PREEMPT Mon Oct 29 13:39:29 CET 2007
> > i386 unknown
> > # cat /proc/cpuinfo
> > clflush size    : 32
> 
> Hm.  This probably shouldn't be displayed when clflush isn't available...

Yup, I noticed as well :)

     tglx

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Mikael Pettersson]

On Sun, 28 Oct 2007 21:34:58 -0700, H. Peter Anvin wrote:
> Mikael Pettersson wrote:
> > My old 486 fails to boot with the 2.6.24-rc1 kernel.
> > Grub loads it, 4 lines of text appear but not the kernel's
> > "Linux version <blah> greet", and the machine reboots.
> > Double-checked with a serial console: nothing appears
> > before it reboots.
> > 
> > All 2.6 kernels up to 2.6.23 worked fine on this machine.
> > 
> > Config is at http://user.it.uu.se/~mikpe/linux/tmp/486-config-2.6.24-rc1.
> > The kernel is unpatched 2.6.24-rc1 compiled with gcc-4.2.2.
> > 
> 
> Any chance you could bisect this problem?

I can try, but it will have to wait until next weekend.

/Mikael

Re: [REGRESSION] 2.6.24-rc1 fails to boot on a 486

[Mikael Pettersson]

On Mon, 29 Oct 2007 14:47:49 +0100 (CET), Thomas Gleixner wrote:
> On Mon, 29 Oct 2007, Mikael Pettersson wrote:
> 
> > On Sun, 28 Oct 2007 21:33:02 -0700, H. Peter Anvin wrote:
> > > Mikael Pettersson wrote:
> > > > My old 486 fails to boot with the 2.6.24-rc1 kernel.
> > > > Grub loads it, 4 lines of text appear but not the kernel's
> > > > "Linux version <blah> greet", and the machine reboots.
> > > > Double-checked with a serial console: nothing appears
> > > > before it reboots.
> > > 
> > > What four lines of text?
> > 
> > They're impossible to capture because they're only visible
> > on the VGA screen for like 0.2 seconds before the machine
> > reboots and the screen is blanked; they don't show up on
> > the serial console.
> > 
> > They look like paths to the vmlinuz and initrd surrounded
> > by [ ] brackets, so I guess they come from grub.
> 
> Any chance to use serial console ?
> 
> Enable CONFIG_EARLY_PRINTK and add
>  
> earlyprintk=serial,ttyS0,115200,keep
> 
> to the kernel command line.

As I mentioned in my first message, I did hook up
a serial console except I used the console=ttyS0,115200
boot parameter, but the kernel rebooted before any
output appeared. I can try the earlyprintk= version
above next time I'm near the 486 if you think it will
make any difference.

> Can you please provide your .config file ?

I posted a link to it in my first message:

>Config is at http://user.it.uu.se/~mikpe/linux/tmp/486-config-2.6.24-rc1.
>The kernel is unpatched 2.6.24-rc1 compiled with gcc-4.2.2.

/Mikael