[uml-devel] kernel module support broken on x86-64?

[uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

Hi!

 I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
seems to be broken. No matter which module I try to load the output 
looks similar to this:

 overflow in relocation type 11 val 80836d41
'loop' likely not compiled with -mcmodel=kernel

After searching for a while I found some threads from 2006 discussing 
this issue, e.g.:
http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
and
http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2

As Andi Kleen has mentioned in a mail from the first thread, simply 
appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
it anyway and can confirm his statement ;)

Since I could not find any solution I've decided to write this mail and 
ask about the current state of this issue and of course for a solution! 
I simply don't want to believe that there is no loadable module support 
for UML in 2008...

Regards
JK

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Re: [uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

[-- Attachment #1.1: Type: text/plain, Size: 1567 bytes --]

Boaz Harrosh wrote:

>juergen.kadidlo@exasol.com wrote:
>  
>
>>Hi!
>>
>> I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>seems to be broken. No matter which module I try to load the output 
>>looks similar to this:
>>
>> overflow in relocation type 11 val 80836d41
>>'loop' likely not compiled with -mcmodel=kernel
>>
>>After searching for a while I found some threads from 2006 discussing 
>>this issue, e.g.:
>>http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>and
>>http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>
>>As Andi Kleen has mentioned in a mail from the first thread, simply 
>>appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>it anyway and can confirm his statement ;)
>>
>>Since I could not find any solution I've decided to write this mail and 
>>ask about the current state of this issue and of course for a solution! 
>>I simply don't want to believe that there is no loadable module support 
>>for UML in 2008...
>>
>>Regards
>>JK
>>
>>    
>>
>
>Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>are you using?
>
>I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>
>Boaz
>
>  
>
I'm glad to here that the bug has been fixed. Anyway, it does not work 
with my configuration:

 - CentOS 5.1 as host system and UML root fs
 - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
 - GCC 4.1.2
 - GLIBC 2.5

Regards
JK







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Re: [uml-devel] kernel module support broken on x86-64?

[Boaz Harrosh]

juergen.kadidlo@exasol.com wrote:
> Boaz Harrosh wrote:
>> juergen.kadidlo@exasol.com wrote:
>>   
>>> Hi!
>>>
>>>  I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>> seems to be broken. No matter which module I try to load the output 
>>> looks similar to this:
>>>
>>>  overflow in relocation type 11 val 80836d41
>>> 'loop' likely not compiled with -mcmodel=kernel
>>>
>>> After searching for a while I found some threads from 2006 discussing 
>>> this issue, e.g.:
>>> http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>> and
>>> http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>>
>>> As Andi Kleen has mentioned in a mail from the first thread, simply 
>>> appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>> it anyway and can confirm his statement ;)
>>>
>>> Since I could not find any solution I've decided to write this mail and 
>>> ask about the current state of this issue and of course for a solution! 
>>> I simply don't want to believe that there is no loadable module support 
>>> for UML in 2008...
>>>
>>> Regards
>>> JK
>>>
>>>     
>>
>> Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>> are you using?
>>
>> I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>> I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>>
>> Boaz
>>
>>   
> I'm glad to here that the bug has been fixed. Anyway, it does not work
> with my configuration:
> 
>  - CentOS 5.1 as host system and UML root fs
>  - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>  - GCC 4.1.2
>  - GLIBC 2.5
> 
> Regards
> JK
> 

I used to run with red-hat 4.5 so this should work.
64 bit, right?

From passed experience I've seen that UML will only
work if I first do "make ARCH=um defconfig"  and then
manually enable any needed options with make xconfig.
other wise it breaks in all kind of ways. Even doing
a make oldconfig on a good uml config file from older
kernel will not work. Try to do defconfig and see if
it loads at all.

How do you compile and run the out-of-tree module
or is it one of the built in modules?

Boaz


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Re: [uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

[-- Attachment #1.1: Type: text/plain, Size: 3610 bytes --]

Boaz Harrosh wrote:

>juergen.kadidlo@exasol.com wrote:
>  
>
>>Boaz Harrosh wrote:
>>    
>>
>>>juergen.kadidlo@exasol.com wrote:
>>>  
>>>      
>>>
>>>>Hi!
>>>>
>>>> I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>>>seems to be broken. No matter which module I try to load the output 
>>>>looks similar to this:
>>>>
>>>> overflow in relocation type 11 val 80836d41
>>>>'loop' likely not compiled with -mcmodel=kernel
>>>>
>>>>After searching for a while I found some threads from 2006 discussing 
>>>>this issue, e.g.:
>>>>http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>>>and
>>>>http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>>>
>>>>As Andi Kleen has mentioned in a mail from the first thread, simply 
>>>>appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>>>it anyway and can confirm his statement ;)
>>>>
>>>>Since I could not find any solution I've decided to write this mail and 
>>>>ask about the current state of this issue and of course for a solution! 
>>>>I simply don't want to believe that there is no loadable module support 
>>>>for UML in 2008...
>>>>
>>>>Regards
>>>>JK
>>>>
>>>>    
>>>>        
>>>>
>>>Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>>>are you using?
>>>
>>>I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>>>I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>>>
>>>Boaz
>>>
>>>  
>>>      
>>>
>>I'm glad to here that the bug has been fixed. Anyway, it does not work
>>with my configuration:
>>
>> - CentOS 5.1 as host system and UML root fs
>> - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>> - GCC 4.1.2
>> - GLIBC 2.5
>>
>>Regards
>>JK
>>
>>    
>>
>
>I used to run with red-hat 4.5 so this should work.
>64 bit, right?
>
From passed experience I've seen that UML will only
>work if I first do "make ARCH=um defconfig"  and then
>manually enable any needed options with make xconfig.
>other wise it breaks in all kind of ways. Even doing
>a make oldconfig on a good uml config file from older
>kernel will not work. Try to do defconfig and see if
>it loads at all.
>
>How do you compile and run the out-of-tree module
>or is it one of the built in modules?
>
>Boaz
>
>  
>
I tried what you've suggested and did the following:
- make mrproper
- make defconfig ARCH=um
- make linux ARCH=um
- make modules ARCH=um
- make modules_install INSTALL_MOD_PATH=/path/to/mounted/uml_root_fs ARCH=um

It did not work (same result).

After that, I copied the kernel source to the uml-root-fs, started the 
UML and did a 'make clean' and 'make modules ARCH=um' inside the running 
UML, followed by a 'make modules_install'. Again, it did not work.

After that, I've extracted the kernel source again (completely vanilla) 
and restarted at 'make defconfig'. Same result.
No module is loadable. They all have 'invalid fomrat' an the usage of 
the '-mcmodel=kernel' flag is suggested.

BTW : with the same sources (and the same commands as listed above) I've 
successfully built a fully working 32 bit UML kernel!

I've also tried kernel 2.6.24.7 with identical results.

Last but not least, I've tried the same with a fresh download of the 
2.6.26 kernel. Unfortunately, this time there was another problem: the 
kernel exits with a panic on startup (tried to build it twice with the 
same result). According to the stack-trace, the panic happens somewhere 
inside "get_page_from_free_list()"...

I'm really running out of ideas right now, does anyone have some 
suggestions?

Regards
JK
 





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Re: [uml-devel] kernel module support broken on x86-64?

[Boaz Harrosh]

juergen.kadidlo@exasol.com wrote:
> Boaz Harrosh wrote:
>> juergen.kadidlo@exasol.com wrote:
>>   
>>> Boaz Harrosh wrote:
>>>     
>>>> juergen.kadidlo@exasol.com wrote:
>>>>   
>>>>       
>>>>> Hi!
>>>>>
>>>>>  I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>>>> seems to be broken. No matter which module I try to load the output 
>>>>> looks similar to this:
>>>>>
>>>>>  overflow in relocation type 11 val 80836d41
>>>>> 'loop' likely not compiled with -mcmodel=kernel
>>>>>
>>>>> After searching for a while I found some threads from 2006 discussing 
>>>>> this issue, e.g.:
>>>>> http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>>>> and
>>>>> http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>>>>
>>>>> As Andi Kleen has mentioned in a mail from the first thread, simply 
>>>>> appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>>>> it anyway and can confirm his statement ;)
>>>>>
>>>>> Since I could not find any solution I've decided to write this mail and 
>>>>> ask about the current state of this issue and of course for a solution! 
>>>>> I simply don't want to believe that there is no loadable module support 
>>>>> for UML in 2008...
>>>>>
>>>>> Regards
>>>>> JK
>>>>>
>>>>>     
>>>>>         
>>>> Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>>>> are you using?
>>>>
>>>> I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>>>> I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>>>>
>>>> Boaz
>>>>
>>>>   
>>>>       
>>> I'm glad to here that the bug has been fixed. Anyway, it does not work
>>> with my configuration:
>>>
>>>  - CentOS 5.1 as host system and UML root fs
>>>  - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>>>  - GCC 4.1.2
>>>  - GLIBC 2.5
>>>
>>> Regards
>>> JK
>>>
>>>     
>>
>> I used to run with red-hat 4.5 so this should work.
>> 64 bit, right?
>>
>> From passed experience I've seen that UML will only
>> work if I first do "make ARCH=um defconfig"  and then
>> manually enable any needed options with make xconfig.
>> other wise it breaks in all kind of ways. Even doing
>> a make oldconfig on a good uml config file from older
>> kernel will not work. Try to do defconfig and see if
>> it loads at all.
>>
>> How do you compile and run the out-of-tree module
>> or is it one of the built in modules?
>>
>> Boaz
>>
>>   
> I tried what you've suggested and did the following:
> - make mrproper
> - make defconfig ARCH=um
> - make linux ARCH=um
> - make modules ARCH=um
> - make modules_install INSTALL_MOD_PATH=/path/to/mounted/uml_root_fs ARCH=um
> 
> It did not work (same result).
> 
> After that, I copied the kernel source to the uml-root-fs, started the
> UML and did a 'make clean' and 'make modules ARCH=um' inside the running
> UML, followed by a 'make modules_install'. Again, it did not work.
> 
> After that, I've extracted the kernel source again (completely vanilla)
> and restarted at 'make defconfig'. Same result.
> No module is loadable. They all have 'invalid fomrat' an the usage of
> the '-mcmodel=kernel' flag is suggested.
> 
> BTW : with the same sources (and the same commands as listed above) I've
> successfully built a fully working 32 bit UML kernel!
> 
> I've also tried kernel 2.6.24.7 with identical results.
> 
> Last but not least, I've tried the same with a fresh download of the
> 2.6.26 kernel. Unfortunately, this time there was another problem: the
> kernel exits with a panic on startup (tried to build it twice with the
> same result). According to the stack-trace, the panic happens somewhere
> inside "get_page_from_free_list()"...
> 
> I'm really running out of ideas right now, does anyone have some
> suggestions?
> 
> Regards
> JK
>  

It all works down here. Just a long shot you have installed uml_utilities
on the host ...

I run the uml from the root of the source tree like this:
./.build_um/vmlinux ubd0=/usr0/var/local/um/Fedora7-AMD64-root_fs eth0=tuntap,,,192.168.0.117 mem=256M
(The .build_um/ is because I use KBUILD_OUTPUT=.build_um so I can compile 
multiple targets from same source tree)

Maybe there is some package missing from the Linux image you are using.
You are using a 64bit Linux image with your 64bit kernel, yes?
Try to compare the 32 bit image with the 64bit one. See if they have
the same packages installed. I started with a ready made fedora7 uml
image and never really touched it much except the occasional yum install
of a library or two.

Boaz
  

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Re: [uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

[-- Attachment #1.1: Type: text/plain, Size: 5600 bytes --]

Boaz Harrosh wrote:

>juergen.kadidlo@exasol.com wrote:
>  
>
>>Boaz Harrosh wrote:
>>    
>>
>>>juergen.kadidlo@exasol.com wrote:
>>>  
>>>      
>>>
>>>>Boaz Harrosh wrote:
>>>>    
>>>>        
>>>>
>>>>>juergen.kadidlo@exasol.com wrote:
>>>>>  
>>>>>      
>>>>>          
>>>>>
>>>>>>Hi!
>>>>>>
>>>>>> I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>>>>>seems to be broken. No matter which module I try to load the output 
>>>>>>looks similar to this:
>>>>>>
>>>>>> overflow in relocation type 11 val 80836d41
>>>>>>'loop' likely not compiled with -mcmodel=kernel
>>>>>>
>>>>>>After searching for a while I found some threads from 2006 discussing 
>>>>>>this issue, e.g.:
>>>>>>http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>>>>>and
>>>>>>http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>>>>>
>>>>>>As Andi Kleen has mentioned in a mail from the first thread, simply 
>>>>>>appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>>>>>it anyway and can confirm his statement ;)
>>>>>>
>>>>>>Since I could not find any solution I've decided to write this mail and 
>>>>>>ask about the current state of this issue and of course for a solution! 
>>>>>>I simply don't want to believe that there is no loadable module support 
>>>>>>for UML in 2008...
>>>>>>
>>>>>>Regards
>>>>>>JK
>>>>>>
>>>>>>    
>>>>>>        
>>>>>>            
>>>>>>
>>>>>Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>>>>>are you using?
>>>>>
>>>>>I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>>>>>I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>>>>>
>>>>>Boaz
>>>>>
>>>>>  
>>>>>      
>>>>>          
>>>>>
>>>>I'm glad to here that the bug has been fixed. Anyway, it does not work
>>>>with my configuration:
>>>>
>>>> - CentOS 5.1 as host system and UML root fs
>>>> - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>>>> - GCC 4.1.2
>>>> - GLIBC 2.5
>>>>
>>>>Regards
>>>>JK
>>>>
>>>>    
>>>>        
>>>>
>>>I used to run with red-hat 4.5 so this should work.
>>>64 bit, right?
>>>
>>>From passed experience I've seen that UML will only
>>>work if I first do "make ARCH=um defconfig"  and then
>>>manually enable any needed options with make xconfig.
>>>other wise it breaks in all kind of ways. Even doing
>>>a make oldconfig on a good uml config file from older
>>>kernel will not work. Try to do defconfig and see if
>>>it loads at all.
>>>
>>>How do you compile and run the out-of-tree module
>>>or is it one of the built in modules?
>>>
>>>Boaz
>>>
>>>  
>>>      
>>>
>>I tried what you've suggested and did the following:
>>- make mrproper
>>- make defconfig ARCH=um
>>- make linux ARCH=um
>>- make modules ARCH=um
>>- make modules_install INSTALL_MOD_PATH=/path/to/mounted/uml_root_fs ARCH=um
>>
>>It did not work (same result).
>>
>>After that, I copied the kernel source to the uml-root-fs, started the
>>UML and did a 'make clean' and 'make modules ARCH=um' inside the running
>>UML, followed by a 'make modules_install'. Again, it did not work.
>>
>>After that, I've extracted the kernel source again (completely vanilla)
>>and restarted at 'make defconfig'. Same result.
>>No module is loadable. They all have 'invalid fomrat' an the usage of
>>the '-mcmodel=kernel' flag is suggested.
>>
>>BTW : with the same sources (and the same commands as listed above) I've
>>successfully built a fully working 32 bit UML kernel!
>>
>>I've also tried kernel 2.6.24.7 with identical results.
>>
>>Last but not least, I've tried the same with a fresh download of the
>>2.6.26 kernel. Unfortunately, this time there was another problem: the
>>kernel exits with a panic on startup (tried to build it twice with the
>>same result). According to the stack-trace, the panic happens somewhere
>>inside "get_page_from_free_list()"...
>>
>>I'm really running out of ideas right now, does anyone have some
>>suggestions?
>>
>>Regards
>>JK
>> 
>>    
>>
>
>It all works down here. Just a long shot you have installed uml_utilities
>on the host ...
>  
>
They are installed.

>I run the uml from the root of the source tree like this:
>.../.build_um/vmlinux ubd0=/usr0/var/local/um/Fedora7-AMD64-root_fs eth0=tuntap,,,192.168.0.117 mem=256M
>(The .build_um/ is because I use KBUILD_OUTPUT=.build_um so I can compile 
>multiple targets from same source tree)
>
>Maybe there is some package missing from the Linux image you are using.
>You are using a 64bit Linux image with your 64bit kernel, yes?
>Try to compare the 32 bit image with the 64bit one. See if they have
>the same packages installed. I started with a ready made fedora7 uml
>image and never really touched it much except the occasional yum install
>of a library or two.
>
>Boaz
>  
>
I already thought about the root fs being the reason for this, but I 
can't imagine how a different root can affect the kernel's ability to 
load modules. It should not be affected by any packages installed, isn't it?
 Anyway, after taking a closer look to your starting command, I noticed 
another difference: I've always been using "mem=512m" on the 64 bit 
system (it's an 8 GB machine). I've tried it with "mem=256" and IT 
FINALLY WORKS! All the kernels I've compiled are working correctly now, 
except for the 2.6.26 which still exits with a panic on startup...

Thank you very much for your help! But I'd really like to know why it 
did not work with "m= 512m". I've always thought that this would only 
alter the max. available memory inside the UML. Maybe this is a bug though?

Regards
JK

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Re: [uml-devel] kernel module support broken on x86-64?

[Boaz Harrosh]

juergen.kadidlo@exasol.com wrote:
> Boaz Harrosh wrote:
>> juergen.kadidlo@exasol.com wrote:
>>   
>>> Boaz Harrosh wrote:
>>>     
>>>> juergen.kadidlo@exasol.com wrote:
>>>>   
>>>>       
>>>>> Boaz Harrosh wrote:
>>>>>     
>>>>>         
>>>>>> juergen.kadidlo@exasol.com wrote:
>>>>>>   
>>>>>>       
>>>>>>           
>>>>>>> Hi!
>>>>>>>
>>>>>>>  I've compiled an UML kernel based on 2.6.25 but loading kernel modules 
>>>>>>> seems to be broken. No matter which module I try to load the output 
>>>>>>> looks similar to this:
>>>>>>>
>>>>>>>  overflow in relocation type 11 val 80836d41
>>>>>>> 'loop' likely not compiled with -mcmodel=kernel
>>>>>>>
>>>>>>> After searching for a while I found some threads from 2006 discussing 
>>>>>>> this issue, e.g.:
>>>>>>> http://www.mail-archive.com/user-mode-linux-devel@lists.sourceforge.net/msg03693.html
>>>>>>> and
>>>>>>> http://marc.info/?l=user-mode-linux-devel&m=115125101012707&w=2
>>>>>>>
>>>>>>> As Andi Kleen has mentioned in a mail from the first thread, simply 
>>>>>>> appending "-mcmodel=kernel" to the KBUILD_CFLAGS does not work (I tried 
>>>>>>> it anyway and can confirm his statement ;)
>>>>>>>
>>>>>>> Since I could not find any solution I've decided to write this mail and 
>>>>>>> ask about the current state of this issue and of course for a solution! 
>>>>>>> I simply don't want to believe that there is no loadable module support 
>>>>>>> for UML in 2008...
>>>>>>>
>>>>>>> Regards
>>>>>>> JK
>>>>>>>
>>>>>>>     
>>>>>>>         
>>>>>>>             
>>>>>> Every thing is fine down here. What host Kernel-gcc-glibc / uml-gcc-glibc
>>>>>> are you using?
>>>>>>
>>>>>> I'm using out-of-tree modules with uml for every kernel since 2.6.19.
>>>>>> I have both Host and UML as x86_64 on FC7 with gcc 4.1.2
>>>>>>
>>>>>> Boaz
>>>>>>
>>>>>>   
>>>>>>       
>>>>>>           
>>>>> I'm glad to here that the bug has been fixed. Anyway, it does not work
>>>>> with my configuration:
>>>>>
>>>>>  - CentOS 5.1 as host system and UML root fs
>>>>>  - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>>>>>  - GCC 4.1.2
>>>>>  - GLIBC 2.5
>>>>>
>>>>> Regards
>>>>> JK
>>>>>
>>>>>     
>>>>>         
>>>> I used to run with red-hat 4.5 so this should work.
>>>> 64 bit, right?
>>>>
>>>> From passed experience I've seen that UML will only
>>>> work if I first do "make ARCH=um defconfig"  and then
>>>> manually enable any needed options with make xconfig.
>>>> other wise it breaks in all kind of ways. Even doing
>>>> a make oldconfig on a good uml config file from older
>>>> kernel will not work. Try to do defconfig and see if
>>>> it loads at all.
>>>>
>>>> How do you compile and run the out-of-tree module
>>>> or is it one of the built in modules?
>>>>
>>>> Boaz
>>>>
>>>>   
>>>>       
>>> I tried what you've suggested and did the following:
>>> - make mrproper
>>> - make defconfig ARCH=um
>>> - make linux ARCH=um
>>> - make modules ARCH=um
>>> - make modules_install INSTALL_MOD_PATH=/path/to/mounted/uml_root_fs ARCH=um
>>>
>>> It did not work (same result).
>>>
>>> After that, I copied the kernel source to the uml-root-fs, started the
>>> UML and did a 'make clean' and 'make modules ARCH=um' inside the running
>>> UML, followed by a 'make modules_install'. Again, it did not work.
>>>
>>> After that, I've extracted the kernel source again (completely vanilla)
>>> and restarted at 'make defconfig'. Same result.
>>> No module is loadable. They all have 'invalid fomrat' an the usage of
>>> the '-mcmodel=kernel' flag is suggested.
>>>
>>> BTW : with the same sources (and the same commands as listed above) I've
>>> successfully built a fully working 32 bit UML kernel!
>>>
>>> I've also tried kernel 2.6.24.7 with identical results.
>>>
>>> Last but not least, I've tried the same with a fresh download of the
>>> 2.6.26 kernel. Unfortunately, this time there was another problem: the
>>> kernel exits with a panic on startup (tried to build it twice with the
>>> same result). According to the stack-trace, the panic happens somewhere
>>> inside "get_page_from_free_list()"...
>>>
>>> I'm really running out of ideas right now, does anyone have some
>>> suggestions?
>>>
>>> Regards
>>> JK
>>>  
>>>     
>>
>> It all works down here. Just a long shot you have installed uml_utilities
>> on the host ...
>>   
> They are installed.
>> I run the uml from the root of the source tree like this:
>> ......./.build_um/vmlinux ubd0=/usr0/var/local/um/Fedora7-AMD64-root_fs eth0=tuntap,,,192.168.0.117 mem=256M
>> (The .build_um/ is because I use KBUILD_OUTPUT=.build_um so I can compile 
>> multiple targets from same source tree)
>>
>> Maybe there is some package missing from the Linux image you are using.
>> You are using a 64bit Linux image with your 64bit kernel, yes?
>> Try to compare the 32 bit image with the 64bit one. See if they have
>> the same packages installed. I started with a ready made fedora7 uml
>> image and never really touched it much except the occasional yum install
>> of a library or two.
>>
>> Boaz
>>   
> I already thought about the root fs being the reason for this, but I
> can't imagine how a different root can affect the kernel's ability to
> load modules. It should not be affected by any packages installed, isn't it?
>  Anyway, after taking a closer look to your starting command, I noticed
> another difference: I've always been using "mem=512m" on the 64 bit
> system (it's an 8 GB machine). I've tried it with "mem=256" and IT
> FINALLY WORKS! All the kernels I've compiled are working correctly now,
> except for the 2.6.26 which still exits with a panic on startup...
> 
> Thank you very much for your help! But I'd really like to know why it
> did not work with "m= 512m". I've always thought that this would only
> alter the max. available memory inside the UML. Maybe this is a bug though?
> 
> Regards
> JK

It is certainly sounds like a bug. I also get problems with 512M but I only
have 1G on my machine and I have lots of initrd configured modules so it 
can be lots of things.
Please use gdb and try to see what fails and report.

$ gdb vmlinux
gdb> run ubd0=/path_to/uml-root_fs eth0=tuntap,,,192.168.0.117 mem=512M

you might need a few continues:
gdb> c
This is expected.

Try to see what happens just before those cryptic error messages of
load failure, also compare the bad run with a good run of 256M

I will try and do the same once I find a bit of time. Perhaps next week.

Thanks
Boaz

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Re: [uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

[-- Attachment #1.1: Type: text/plain, Size: 4588 bytes --]

Boaz Harrosh schrieb:
> juergen.kadidlo@exasol.com wrote:
> <snip>
>   
>> except for the 2.6.26 which still exits with a panic on startup...
>>
>>     
>
> BTW: v2.6.26 checkout from Linus git crashes for me too
> 2.6.27-rc1 is fine (except it has another problem which I'm bisecting now)
>
> here is the BUG_ON trace:
> Stub registers -
>         0 - 0
>         1 - 0
>         2 - 0
>         3 - 0
>         4 - 0
>         5 - 0
>         6 - 0
>         7 - 0
>         8 - 0
>         9 - 0
>         10 - 0
>         11 - 0
>         12 - 0
>         13 - 0
>         14 - 0
>         15 - ffffffffffffffff
>         16 - 0
>         17 - 33
>         18 - 10216
>         19 - 2aaaaaab0f30
>         20 - 2b
>         21 - 2aaaaaaad910
>         22 - 0
>         23 - 0
>         24 - 0
>         25 - 0
>         26 - 0
> wait_stub_done : failed to wait for SIGTRAP, pid = 1348, n = 1348, errno = 0, status = 0xb7f
> Kernel panic - not syncing: Attempted to kill init!
>
> Modules linked in:
> Pid: 1, comm: swapper Not tainted 2.6.26
> RIP: 0033:[<000000319e430a57>]
> RSP: 00007fff26d69cd8  EFLAGS: 00000206
> RAX: 0000000000000000 RBX: 000000000000053e RCX: ffffffffffffffff
> RDX: 0000000000000000 RSI: 0000000000000013 RDI: 000000000000053e
> RBP: 00007fff26d69d00 R08: 0000000000000000 R09: 00007fff26d69d00
> R10: 0000000000000000 R11: 0000000000000206 R12: 000000000000053a
> R13: 0000000000000004 R14: 00007fff26d6b58c R15: 00007fff26d69fc0
> Call Trace:
> 6fc21778:  [<60013bc1>] panic_exit+0x2f/0x45
> 6fc21798:  [<600412f5>] notifier_call_chain+0x33/0x5b
> 6fc217d8:  [<60041326>] __atomic_notifier_call_chain+0x9/0xb
> 6fc217e8:  [<60041337>] atomic_notifier_call_chain+0xf/0x11
> 6fc217f8:  [<6002b8a1>] panic+0xe6/0x17d
> 6fc21818:  [<60053abe>] get_page_from_freelist+0x2a1/0x41f
> 6fc218b8:  [<6006a144>] kmem_cache_free+0x55/0x5e
> 6fc218e8:  [<6002eca3>] do_exit+0x6b/0x694
> 6fc21908:  [<60036bcd>] __dequeue_signal+0x10e/0x172
> 6fc21958:  [<6002f35c>] do_group_exit+0x90/0xbf
> 6fc21998:  [<60037c30>] get_signal_to_deliver+0x2ca/0x318
> 6fc219b8:  [<60026b7f>] wake_up_state+0xb/0xd
> 6fc219f8:  [<6001202d>] do_signal+0x1f8/0x2ca
> 6fc21a58:  [<6002023a>] set_signals+0x1c/0x2e
> 6fc21a78:  [<6003644f>] force_sig_info+0xb0/0xbf
> 6fc21ae8:  [<60013a26>] fatal_sigsegv+0x28/0x2d
> 6fc21b08:  [<60022647>] wait_stub_done+0xbd/0xc8
> 6fc21b48:  [<60021dd0>] do_syscall_stub+0xbb/0x1b6
> 6fc21b88:  [<60022032>] run_syscall_stub+0xd1/0xdd
> 6fc21bc8:  [<60023396>] write_ldt_entry+0x111/0x180
> 6fc21c48:  [<600235e4>] init_new_ldt+0x1df/0x303
> 6fc21c68:  [<60053cd6>] __alloc_pages_internal+0x9a/0x36e
> 6fc21cb8:  [<60053fc0>] __alloc_pages+0xb/0xd
> 6fc21d18:  [<60013fa4>] init_new_context+0xc9/0x10d
> 6fc21d28:  [<6002ab7b>] mm_alloc+0x4c/0x53
> 6fc21d58:  [<600711ce>] bprm_mm_init+0x4c/0x168
> 6fc21da8:  [<60071f6a>] do_execve+0x89/0x1db
> 6fc21dd8:  [<6000a854>] tcp_congestion_default+0x0/0x10
> 6fc21df8:  [<60010257>] execve1+0x27/0x42
> 6fc21e28:  [<600102cf>] um_execve+0xd/0x36
> 6fc21e38:  [<6006b945>] do_sys_open+0xc9/0xd8
> 6fc21e48:  [<60012354>] kernel_execve+0x2d/0x38
> 6fc21e78:  [<6000ff72>] run_init_process+0x1a/0x1c
> 6fc21e88:  [<60010029>] init_post+0xb5/0xe0
> 6fc21ea8:  [<60001574>] kernel_init+0x1d8/0x1e9
> 6fc21f48:  [<6001f309>] run_kernel_thread+0x41/0x4a
> 6fc21f58:  [<6000139c>] kernel_init+0x0/0x1e9
> 6fc21f98:  [<6001f2f0>] run_kernel_thread+0x28/0x4a
> 6fc21fc8:  [<600114be>] new_thread_handler+0x67/0x91
>
> Terminated
>   
Just want to mention that the stack trace looks identical here (using 
the 2.6.26 stable kernel)...
> Is there a plan to fix this for the 2.6.26 stable ?
>
> Please forgive me if this is old news and it's already
> been reported.
>
> Boaz
>   


-- 
Mit freundlichen Grüßen
Jürgen Kadidlo
---
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Developer
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Re: [uml-devel] kernel module support broken on x86-64?

[Jeff Dike]

On Thu, Aug 07, 2008 at 07:00:53PM +0300, Boaz Harrosh wrote:
> Jeff: Is this queued for 2.6.26-stable ?

I sent it in before I went on vacation, and it should be in -stable by now.

       	     	      Jeff

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Re: [uml-devel] kernel module support broken on x86-64?

[Jeff Dike]

On Tue, Aug 05, 2008 at 06:37:18PM +0200, juergen.kadidlo@exasol.com wrote:
> I'm glad to here that the bug has been fixed. Anyway, it does not work  
> with my configuration:
>
> - CentOS 5.1 as host system and UML root fs
> - Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
> - GCC 4.1.2
> - GLIBC 2.5

I'm not sure that anything was ever broken.

You are building the modules against a UML tree, with ARCH=um on the
make line?  I.e. you're not trying to load a host module into UML?

     	    	 	    Jeff

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Re: [uml-devel] kernel module support broken on x86-64?

[juergen.kadidlo]

[-- Attachment #1.1: Type: text/plain, Size: 1036 bytes --]

Jeff Dike wrote:

>On Tue, Aug 05, 2008 at 06:37:18PM +0200, juergen.kadidlo@exasol.com wrote:
>  
>
>>I'm glad to here that the bug has been fixed. Anyway, it does not work  
>>with my configuration:
>>
>>- CentOS 5.1 as host system and UML root fs
>>- Kernel 2.6.25.4 (vanilla, but config taken from the CentOS kernel)
>>- GCC 4.1.2
>>- GLIBC 2.5
>>    
>>
>
>I'm not sure that anything was ever broken.
>  
>
According to the links from my first mail, there has been a bug in UML 
that caused that problem and I could not find anything that proved that 
it has been fixed...

>You are building the modules against a UML tree, with ARCH=um on the
>make line?  I.e. you're not trying to load a host module into UML?
>
>     	    	 	    Jeff
>
>  
>
It's not the first time I'm compiling an UML kernel but it is the first 
time I'm building a 64 bit version. Don't get me wrong, I would never 
claim to not make mistakes, but the reason is definitily not a forgotten 
"ARCH=um" or a wrong path, I've triple-checked this...

Regards
JK


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