[okl4-developer] Using OKLinux to provide services

[Geoffrey Lee]

On Wed, Aug 06, 2008 at 08:41:07PM +1000, Joshua Root wrote:
> Damien Schulz wrote:
> > Hi Geoffrey,
> > 
> > the pagefault happens in the function dequeue_task of the Linux kernel. Any idea what could cause this problem?
> > 
> > 01f09110 <dequeue_task>:
> >  1f09110:	e1a0c00d 	mov	ip, sp
> >  1f09114:	e92dd830 	stmdb	sp!, {r4, r5, fp, ip, lr, pc}
> >  1f09118:	e2804020 	add	r4, r0, #32	; 0x20
> >  1f0911c:	e24cb004 	sub	fp, ip, #4	; 0x4
> >  1f09120:	e3a02601 	mov	r2, #1048576	; 0x100000
> >  1f09124:	e2822c01 	add	r2, r2, #256	; 0x100
> >  1f09128:	e2815004 	add	r5, r1, #4	; 0x4
> >  1f0912c:	e5913000 	ldr	r3, [r1]                                    <-- crash
> >  1f09130:	e2433001 	sub	r3, r3, #1	; 0x1
> >  1f09134:	e5813000 	str	r3, [r1]
> 
> Well, r1 would be the second argument, which means it's being passed a 
> null task_struct pointer. Why that would be, I don't know.


I am guessing because the mutex can sleep and since the ipc loop 
is freestanding and not associated with any Linux task_struct-based
thread so calling Linux down() and up() is not allowed.

> 
> - Josh


	-gl

> 
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