[Linux-ia64] Kernel dumps stacks while calling exported function from a loadable module

[Linux-ia64] Kernel dumps stacks while calling exported function from a loadable module

[Jeff Lee]

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Hello everyone, 

I am having trouble in calling exported functions on my RH 7.2 box.
running 2.4.9-18 kernel.  The calling module causes kernel stack dumps
with messages like this:

insmod[1508]: Unimplemented Instruction Address fault 4398046511120
Using_Versions [] 0x2047fff <-- 
::

My modules are really trivial.  The one exported a dummy function is
listed below:

void dummy(void)
{
  printk("Dummy is called!\n");
}

int init_module(void)      
{ 
  printk("<1>Hello, world\n"); 
  return 0; 
}

And the calling module looks like this:

extern void dummy(void);

int init_module(void)      
{ 
  printk("<00>Hello, world\n"); 
  dummy();
  printk("done\n"); 
  return 0; 
}


The compilation line looks like this:

/opt/gcc3.1/bin/gcc -c -DLINUX -D__SMP__ -D"__BOOT_KERNEL_SMP=1"
-D"__BOOT_KERNEL_UP=0"  -O2 -Wall -Wstrict-prototypes  -D__ia64__ -D_LP64
-ffixed-r13 -mfixed-range=f10-f15,f32-f127 -falign-functions=32
-fno-common -Wno-unused -mb-step -I -I/usr/src/linux-2.4/drivers/scsi -I
-I/scsi  -I/usr/src/linux-2.4/drivers/scsi -DMODULE -DMODVERSIONS -include
/usr/src/linux-2.4/include/linux/modversions.h-D__KERNEL__  myhello1.c

The module that exports function loads without any problems but the
calling module fails.  

Any input regarding this matter is greatly appreciated.


Jeff Lee


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Re: [Linux-ia64] Kernel dumps stacks while calling exported function from a loadable module

[Matthew Wilcox]

On Tue, Aug 20, 2002 at 05:52:32PM +0800, Jeff Lee wrote:
> I am having trouble in calling exported functions on my RH 7.2 box.
> running 2.4.9-18 kernel.  The calling module causes kernel stack dumps

My understanding is that this kernel was compiled with gcc 2.96 ...

> The compilation line looks like this:
> 
> /opt/gcc3.1/bin/gcc -c -DLINUX -D__SMP__ -D"__BOOT_KERNEL_SMP=1"
> -D"__BOOT_KERNEL_UP=0"  -O2 -Wall -Wstrict-prototypes  -D__ia64__ -D_LP64
> -ffixed-r13 -mfixed-rangeñ0-f15,f32-f127 -falign-functions2
> -fno-common -Wno-unused -mb-step -I -I/usr/src/linux-2.4/drivers/scsi -I
> -I/scsi  -I/usr/src/linux-2.4/drivers/scsi -DMODULE -DMODVERSIONS -include
> /usr/src/linux-2.4/include/linux/modversions.h-D__KERNEL__  myhello1.c

... and you're using gcc 3.1, so maybe this compiler mismatch is causing
the problem?

-- 
Revolutions do not require corporate support.

Re: [Linux-ia64] Kernel dumps stacks while calling exported function from a loadable module

[Richard Hirst]

On Tue, Aug 20, 2002 at 07:41:47PM +0800, Jeff Lee wrote:
> My kernel was from the RH installation CD.  I haven't touched it yet.
> 
> I used gcc3.1 for a reason: the 2.96 gcc causes the same problem; hence I tried gcc3.1 but that doesn't seem to matter,
> 
> Actually, I tried a little experiment.  I printed the address of dummy() out;  surprisingly, the reading of dummy() is different in the exporting module from the calling module (no wonder the kernel stacks).  But, any other global variables look fine.  
> 
> What so special about the kernel function symbols in IA 64?

A pointer to a function on ia64 is actually a pointer to a struct
containing the address of the function and the data pointer to use in
the function.

Richard

RE: [Linux-ia64] Kernel dumps stacks while calling exported function from a loadable module

[Jeff Lee]

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