Re: nice little oops

[Rick Hohensee]

> 
> On Tue, 25 Jan 100, Rick Hohensee wrote:
> 
> > Partition check:
> >  sda: sda1
> >  sdb: sdb1
> > VFS: Insert root floppy and press ENTER
> > Unable to handle kernel null pointer dereference at virtual address 00000008
> > current->tss.cr3 = 00101000, %cr3 = 00101000
> > *pde = 00000000
> > Oops: 0000
> > CPU:    0
> > EIP:    0010:[<c0128410>]
> > EFLAGS: 00010206
> > eax: 00000000   ebx: 00000000   ecx: c009df84   edx: c0310000
> > esi: 00000000   edi: 00000000   ebp: c009df84   esp: c009df20
> > ds: 0018   es: 0018    ss: 0018
> > Process swapper (pid: 1, process nr: 1, stackpage=c0096000)
> > Stack: 00000000 00000000 00000000 00000000 c019658b c009df84 00000000
> >        c009df84 c031c000 000003ee ffffffff c0080000 c031c000 c009df84
> >        c009c000 c031c000 c009df84 c029ba6e c031c000 c009df84 c0297fd8
> > Call Trace: [<c019658b>] [<c0124213>] [<c0106093>] [<c01065d3>]
> > Code: 8b 40 08 0f b7 40 2a 50 e8 33 c4 ff ff 83 c4 04 c3 90 90 90
> 
> This is pretty useless unless you run it through ksymoops. Please do so...

I don't have that. (I also don't have C++. What's the no-C++ ksyms thing?)

The same thing happens on a Pentium IDE box.
The register dump is different but the Code: is the same.
Care to see for yourself?
ftp://linux01.gwdg.de/pub/cLIeNUX/interim/Viralinux_II .

Jan 23 09:39  text/plain       ViraLinux_II  1440Kb
"If your browser insists on rendering this as text, upgrade to Lynx or FTP."

cp the above to a floppy. 
write-protect. 
Reboot with that in the drive. 
Hit enter at the LILO prompt/message
Hit enter at "VFS: Insert root floppy.."
oops.

>  
> > Fatal. 
> > 
> > I hope there's no typos.
> > 
> > This is caused by trying to mount / on a write-protected 1.44 meg ext2 
> > floppy. 
> > 
> > This is a 2.1.12 MCA/PCI/kitchen_sink kernel with the realtime 
> > patch. The box is a PS/2 9590, 2.88 meg floppy drive.
> 
> That box doesn't need PCI-support... :^)

That floppy is geared to boot on as many x86en as possible without modules.
It will boot with no HD. (That may take some fancy LILO kernel args.
The only time I've booted something like this with no HD was with the
skip-IO-region thing to get past an MCA RAID adapter. So actually it's
known to boot *thinking* there's no HD.)

> 
> > Rick Hohensee 
> > cLIeNUX user 0
> > (The floppy, BTW, has 2 Forths, ash, the kernel, and 300k free space.
> > Uncompressed. ) 
> 
> I suppose you utilise an ED-floppy (2.88 MB) then?

Nope :o)

That's a 1.44 meg floppy, as I said. Notice that I didn't list libc.
(pre-quote)"Well, that's pretty useless without libc." 
Not entirely. My Forths have all the Linux syscalls available as
keywords. Commands like "sync", "getpid" and so on are no code. Syscalls 
that take arguments need some code. A wrapper for mount e.g. would add 
something like 100 bytes to the size of one of the Forths. 

BTW, I have as much success going to 2.88 with 1.44 diskettes 
as with actual ED-marked ones, which I'm stingey (stinjy?) with.

Hmmmm. Is there a need for a general way to generate an oops?
This looks pretty general. Meanwhile, it's a dessert-topping AND
an alternate user-space!

Rick Hohensee
:; cLIeNUX0 /dev/tty3 r 16:13:05   /
:;d -s /ViraLinux_IIdl
1447 /ViraLinux_IIdl

> 
> /David
>   _                                                                 _ 
>  // David Weinehall <[e-mail]> /> Northern lights wander      \\
> //  Project MCA Linux hacker        //  Dance across the winter sky // 
> \>  http://www.acc.umu.se/~tao/    </   Full colour fire           </ 
>