/linuxrc link to /bin/busybox causes booting to fail (sysvinit should be used instead)

/linuxrc link to /bin/busybox causes booting to fail (sysvinit should be used instead)

[David Huggins-Daines]

Hi,

When booting base-image or minimal-image from a ramdisk, I get errors 
like the following:

RAMDISK: Compressed image found at block 0
VFS: Mounted root (ext2 filesystem) on device 1:0.
init started: BusyBox v1.13.2 (2009-04-03 15:54:42 EDT)
Bad inittab entry at line 5
can't open /dev/si: No such file or directory
can't open /dev/~~: No such file or directory
can't open /dev/l0: No such file or directory
can't open /dev/l1: No such file or directory
can't open /dev/l2: No such file or directory
can't open /dev/l3: No such file or directory
can't open /dev/l4: No such file or directory
can't open /dev/l5: No such file or directory
can't open /dev/l6: No such file or directory
can't open /dev/z6: No such file or directory
can't open /dev/S: No such file or directory
process '/sbin/sulogin' (pid 167) exited. Scheduling for restart.
process '/sbin/getty 57600 ttyAM0' (pid 168) exited. Scheduling for restart.

This is because, even though /sbin/init points to /sbin/init.sysvinit, 
there is also a /linuxrc -> /bin/busybox link, which the kernel uses in 
preference, causing busybox to run as 'init'.  The problem is that  
busybox init uses a different syntax from sysvinit.

I think this problem might have started when inittab support was added 
to busybox...

Is there a good reason for that /linuxrc link?  And if not, where is it 
coming from, so that I can remove it?

Thanks!

Re: /linuxrc link to /bin/busybox causes booting to fail (sysvinit should be used instead)

[Denys Dmytriyenko]

On Fri, Apr 03, 2009 at 04:44:57PM -0400, David Huggins-Daines wrote:
> Hi,
>
> When booting base-image or minimal-image from a ramdisk, I get errors like 
> the following:
>
> RAMDISK: Compressed image found at block 0
> VFS: Mounted root (ext2 filesystem) on device 1:0.
> init started: BusyBox v1.13.2 (2009-04-03 15:54:42 EDT)
> Bad inittab entry at line 5
> can't open /dev/si: No such file or directory
> can't open /dev/~~: No such file or directory
> can't open /dev/l0: No such file or directory
> can't open /dev/l1: No such file or directory
> can't open /dev/l2: No such file or directory
> can't open /dev/l3: No such file or directory
> can't open /dev/l4: No such file or directory
> can't open /dev/l5: No such file or directory
> can't open /dev/l6: No such file or directory
> can't open /dev/z6: No such file or directory
> can't open /dev/S: No such file or directory

Usually that's caused by bad bootargs...
Otherwise images boot fine even with /linuxrc pointing to /bin/busybox

> process '/sbin/sulogin' (pid 167) exited. Scheduling for restart.
> process '/sbin/getty 57600 ttyAM0' (pid 168) exited. Scheduling for 
> restart.
>
> This is because, even though /sbin/init points to /sbin/init.sysvinit, 
> there is also a /linuxrc -> /bin/busybox link, which the kernel uses in 
> preference, causing busybox to run as 'init'.  The problem is that  busybox 
> init uses a different syntax from sysvinit.
>
> I think this problem might have started when inittab support was added to 
> busybox...
>
> Is there a good reason for that /linuxrc link?  And if not, where is it 
> coming from, so that I can remove it?

-- 
Denys

Re: /linuxrc link to /bin/busybox causes booting to fail (sysvinit should be used instead)

[Koen Kooi]

On 03-04-09 22:44, David Huggins-Daines wrote:
> Hi,
>
> When booting base-image or minimal-image from a ramdisk, I get errors
> like the following:

Do you have 
http://cgit.openembedded.net/cgit.cgi?url=openembedded/commit/&id=5261978d6f9600640c1ea4f1393e18772d4f9657 
in your OE tree?

regards,

Koen

Re: /linuxrc link to /bin/busybox causes booting to fail, (sysvinit should be used instead)

[David Huggins-Daines]

>
> On 03-04-09 22:44, David Huggins-Daines wrote:
>> > Hi,
>> >
>> > When booting base-image or minimal-image from a ramdisk, I get errors
>> > like the following:
>>     
>
> Do you have 
> http://cgit.openembedded.net/cgit.cgi?url=openembedded/commit/&id=5261978d6f9600640c1ea4f1393e18772d4f9657 
> in your OE tree?
>   
I do, I think, but actually I discovered the reason for this.  It's a 
subtlety of the Linux boot process which I didn't previously 
understand.  Basically the kernel will use /linuxrc as init if and only 
if the root filesystem on the command line is different from the root 
partition.  So if you are using a ramdisk root (and not an initrd), you 
need to put root=/dev/ram0 on the kernel command line.

Re: /linuxrc link to /bin/busybox causes booting to fail, (sysvinit should be used instead)

[Denys Dmytriyenko]

On Tue, Apr 07, 2009 at 10:37:19AM -0400, David Huggins-Daines wrote:
>>
>> On 03-04-09 22:44, David Huggins-Daines wrote:
>>> > Hi,
>>> >
>>> > When booting base-image or minimal-image from a ramdisk, I get errors
>>> > like the following:
>>
>> Do you have 
>> http://cgit.openembedded.net/cgit.cgi?url=openembedded/commit/&id=5261978d6f9600640c1ea4f1393e18772d4f9657 
>> in your OE tree?
>>   
> I do, I think, but actually I discovered the reason for this.  It's a 
> subtlety of the Linux boot process which I didn't previously understand.  
> Basically the kernel will use /linuxrc as init if and only if the root 
> filesystem on the command line is different from the root partition.  So if 
> you are using a ramdisk root (and not an initrd), you need to put 
> root=/dev/ram0 on the kernel command line.

As I told you before - your bootargs is to blame. Sorry I was not very 
specific, but I've seen it fail the same exact way when there was a spelling 
problem in root= option or it was missing entirely...

-- 
Denys