Re: problem bring up initramfs and busybox

[myuboot@fastmail.fm]

On Tue, 17 Nov 2009 10:33 +0100, "Ralf Baechle" <ralf@linux-mips.org>
wrote:
> On Mon, Nov 16, 2009 at 06:21:21PM -0600, myuboot@fastmail.fm wrote:
> 
> > I have been struggling to bring up a MIPS 32 board with busybox with or
> > without initramfs.
> > The kernel stucks there without the shell coming up.
> > 
> > [    1.153000] nf_conntrack version 0.5.0 (1024 buckets, 4096 max)
> > [    1.161000] ip_tables: (C) 2000-2006 Netfilter Core Team
> > [    1.167000] TCP cubic registered
> > [    1.170000] NET: Registered protocol family 17
> > [   25.971000] Freeing unused kernel memory: 1032k freed
> > [   39.969000] Algorithmics/MIPS FPU Emulator v1.5
> > 
> > 
> > What I tried here is to use initramfs with statically linked busybox.
> > The initramfs seems to be up, and runs the commands in the /init one by
> > one, and then it goes to a inifite loop in r4k_wait at
> > arch/mips/kernel/genex.S.
> 
> r4k_wait is called by the idle loop.  Which means the kernel has no
> process
> to run so runs the idle loop.  This might be because there is no other
> process left running or because all processes are waiting for I/O for
> example.  So it's not uncommon that even busy systems ocasionally briefly
> run the idle loop.  In other words, seeing the processor executing
> r4k_wait does not necessarily mean something went wrong.  In this case -
> also along with the other information you've provieded it's not obvious
> what has gone wrong.
> 
>   Ralf

According to an email from Kevin, I added a symbolic link from
switch_root to busybox. The switch_root seems to be found now based on
the execution sequence, but I got the following error - "Kernel panic -
not syncing: Attempted to kill init!". This is the same error when I
tried to start the shell without initramfs. Something must be wrong, but
I can't quite figure out.

[    9.250000] Freeing unused kernel memory: 1032k freed
[   10.463000] Algorithmics/MIPS FPU Emulator v1.5
[   41.695000] Kernel panic - not syncing: Attempted to kill init!
[   41.701000] Rebooting in 3 seconds.

Thanks for your help. Andrew

(gdb) c
Continuing.

Breakpoint 2, do_execve (filename=0x9780a000 "/init", argv=0x943dd2bc,
envp=0x943dd230, regs=0x97819e30)
    at fs/exec.c:1293
1293            retval = unshare_files(&displaced);
(gdb) c
Continuing.

Breakpoint 2, do_execve (filename=0x9780a000 "/sbin/switch_root",
argv=0x4f7450, envp=0x4f7464, regs=0x97819f30)
    at fs/exec.c:1293
1293            retval = unshare_files(&displaced);
(gdb) c
Continuing.