2.6.19 rc6 rt3 on embedded ARM system

2.6.19 rc6 rt3 on embedded ARM system

[Dirk Behme]

Hi,

playing with patch-2.6.19-rc6-rt3 on an embedded TI OMAP 
based ARM926 system I encountered two issues.

First, I got the system booting and even playing MP3 via NFS 
using madplay on ALSA works :)

But after madplay stops, I got an Oops:

kernel BUG at kernel/rtmutex.c:672!
Unable to handle kernel NULL pointer dereference at virtual
address 00000000
pgd = c0004000
[00000000] *pgd=00000000
Internal error: Oops: 817 [#1]
PC is at __bug+0x44/0x58
LR is at rt_up+0x4c/0x6c
...

Any ideas what's wrong here? Note that I used recent OMAP 
git and not OMAP mainline so I manually had to convert some 
spinlock_t to raw_spinlock_t.

Second, I tried to compile cyclictest 0.11. Seems that for 
me it isn't so easy as described on [1] "Get the latest 
source tarball, untar into a directory of your choice and 
run make in the source directory.":

~/cyclictest> make
arm-linux-gcc -Wall -O2  -lpthread -lrt cyclictest.c -o 
cyclictest
cyclictest.c: In function 'timerthread':
cyclictest.c:153: error: 'SIGEV_THREAD_ID' undeclared (first 
use in this function)
cyclictest.c:153: error: (Each undeclared identifier is 
reported only once
cyclictest.c:153: error: for each function it appears in.)
cyclictest.c:155: error: 'union <anonymous>' has no member 
named '_tid'
cyclictest.c: At top level:
cyclictest.c:318: error: 'CLOCK_MONOTONIC' undeclared here 
(not in a function)

Looking into kernel headers, SIGEV_THREAD_ID and 
CLOCK_MONOTONIC are defined by kernels include files, but 
seems that they are not included here correctly. Defining 
them manually in cyclictest.c then results in

cyclictest.c:158: error: 'union <anonymous>' has no member 
named '_tid'

And here, I stopped because my _sigev_un in 
include/bits/siginfo.h really contains no _tid:

   struct
	  {
	    void (*_function) (sigval_t);	/* Function to start.  */
	    void *_attribute;			/* Really pthread_attr_t.  */
	  } _sigev_thread;
       } _sigev_un;

I use a gcc 4.1.0 toolchain built with crosstool with 
glibc-2.3.2:

~/cyclictest> arm-linux-gcc -v
Using built-in specs.
Target: arm-linux
Configured with: 
/crossgcc/arm/arm_gcc_4_1_0/crosstool-0.42/build/arm-linux/gcc-4.1.0-glibc-2.3.2/gcc-4.1.0/configure 
--target=arm-linux --host=i686-host_pc-linux-gnu 
--prefix=/usr/arm/arm-linux 
--with-headers=/usr/arm-linux/arm-linux/include 
--with-local-prefix=/usr/arm-linux/arm-linux --disable-nls 
--enable-threads=posix --enable-symvers=gnu 
--enable-__cxa_atexit --enable-languages=c,c++ 
--enable-shared --enable-c99 --enable-long-long
Thread model: posix
gcc version 4.1.0

Any ideas here as well?

[1] http://rt.wiki.kernel.org/index.php/Cyclictest

Re: 2.6.19 rc6 rt3 on embedded ARM system

[Robert Schwebel]

On Sun, Nov 19, 2006 at 06:36:03PM +0100, Dirk Behme wrote:
> playing with patch-2.6.19-rc6-rt3 on an embedded TI OMAP 
> based ARM926 system I encountered two issues.
> 
> First, I got the system booting and even playing MP3 via NFS 
> using madplay on ALSA works :)
> 
> But after madplay stops, I got an Oops:
> 
> kernel BUG at kernel/rtmutex.c:672!
> Unable to handle kernel NULL pointer dereference at virtual
> address 00000000
> pgd = c0004000
> [00000000] *pgd=00000000
> Internal error: Oops: 817 [#1]
> PC is at __bug+0x44/0x58
> LR is at rt_up+0x4c/0x6c
> ...
> 
> Any ideas what's wrong here? 

You snipped the stack trace here, which could offer some information
about the call path. Could you post it?

> Second, I tried to compile cyclictest 0.11. Seems that for 
> me it isn't so easy as described on [1] "Get the latest 
> source tarball, untar into a directory of your choice and 
> run make in the source directory.":
> 
> ~/cyclictest> make
> arm-linux-gcc -Wall -O2  -lpthread -lrt cyclictest.c -o 

Sidenote: these days it doesn't really make sense any more to have
something like an arm-linux-gcc, as you can decide between different
cores (v4, v4t, v5, ...), different floating/fixed point models (hard
fpa, hard vfp, soft vfp, maverick crunch, iwmmxt, ...) etc. 

> cyclictest
> cyclictest.c: In function 'timerthread':
> cyclictest.c:153: error: 'SIGEV_THREAD_ID' undeclared (first 
> use in this function)

Hmm, it looks like SIGEV_THREAD_ID is not defined in the POSIX standard.
Maybe tglx can comment on where this comes from. 

Nevertheless, for me it is defined in bits/siginfo.h, both on debian
unstable (x86) and in our self built gccs; checked with

	arm-v4t-linux-gnueabi/gcc-4.2-20061031-glibc-2.5
	arm-v4t-linux-gnueabi/gcc-4.1.1-glibc-2.5

The include file comes in correctly by including signals.h and is a
glibc header file.

> cyclictest.c:318: error: 'CLOCK_MONOTONIC' undeclared here 
> (not in a function)

The POSIX manpage for timer_create() says that you have to define
signal.h and time.h, the latter one pulls in bits/time.h, which contains
CLOCK_MONOTONIC. This is also a glibc header file.

Maybe your glibc is too old?

> Looking into kernel headers, SIGEV_THREAD_ID and 
> CLOCK_MONOTONIC are defined by kernels include files, but 
> seems that they are not included here correctly. Defining 
> them manually in cyclictest.c then results in
> 
> cyclictest.c:158: error: 'union <anonymous>' has no member 
> named '_tid'
> 
> And here, I stopped because my _sigev_un in 
> include/bits/siginfo.h really contains no _tid:
> 
>   struct
> 	  {
> 	    void (*_function) (sigval_t);	/* Function to start.  */
> 	    void *_attribute;			/* Really pthread_attr_t.  */
> 	  } _sigev_thread;
>       } _sigev_un;

It contains _tid in later glibcs.

> I use a gcc 4.1.0 toolchain built with crosstool with glibc-2.3.2:

I assume glibc-2.3.2 is too old.

Robert 
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
     Hannoversche Str. 2, 31134 Hildesheim, Germany
   Phone: +49-5121-206917-0 |  Fax: +49-5121-206917-9

Re: 2.6.19 rc6 rt3 on embedded ARM system

[Dirk Behme]

Robert Schwebel wrote:
> On Sun, Nov 19, 2006 at 06:36:03PM +0100, Dirk Behme wrote:
> 
>>playing with patch-2.6.19-rc6-rt3 on an embedded TI OMAP 
>>based ARM926 system I encountered two issues.
>>
>>First, I got the system booting and even playing MP3 via NFS 
>>using madplay on ALSA works :)
>>
>>But after madplay stops, I got an Oops:
>>
>>kernel BUG at kernel/rtmutex.c:672!
>>Unable to handle kernel NULL pointer dereference at virtual
>>address 00000000
>>pgd = c0004000
>>[00000000] *pgd=00000000
>>Internal error: Oops: 817 [#1]
>>PC is at __bug+0x44/0x58
>>LR is at rt_up+0x4c/0x6c
>>...
>>Any ideas what's wrong here? 
> 
> You snipped the stack trace here, which could offer some information
> about the call path. Could you post it?

Thought for whoever coded this explicit bug statement info 
above would be sufficient ;)

Ah! Thanks for directing me to the details. Looks like I 
missed one spinlock -> raw_spinlock conversion...

> 	arm-v4t-linux-gnueabi/gcc-4.2-20061031-glibc-2.5
> 	arm-v4t-linux-gnueabi/gcc-4.1.1-glibc-2.5
...
>>I use a gcc 4.1.0 toolchain built with crosstool with glibc-2.3.2:
> 
> I assume glibc-2.3.2 is too old.

Yeah, thanks. A toolchain with glibc 2.3.6 seem to make the 
job. Maybe this is worth a hint in wiki?

Cheers

Dirk

Re: 2.6.19 rc6 rt3 on embedded ARM system

[Robert Schwebel]

On Sun, Nov 19, 2006 at 08:27:02PM +0100, Dirk Behme wrote:
> >I use a gcc 4.1.0 toolchain built with crosstool with glibc-2.3.2:
> >I assume glibc-2.3.2 is too old.
> 
> Yeah, thanks. A toolchain with glibc 2.3.6 seem to make the 
> job. Maybe this is worth a hint in wiki?

We could add a section to the HOWTO, so the question is which are the
toolchain versions we minimally need? It's probably architecture
dependend as well.

Any knowldgable folks around who might have an idea?

Robert
-- 
 Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
 Pengutronix - Linux Solutions for Science and Industry
   Handelsregister:  Amtsgericht Hildesheim, HRA 2686
     Hannoversche Str. 2, 31134 Hildesheim, Germany
   Phone: +49-5121-206917-0 |  Fax: +49-5121-206917-9