Since the process virtual address which are used on the user space stack are not
directly available from the context of the kernel, you will need to do some
virtual address translation to access teh stack frames you are interested in.  I
would suggest that you look at the source code for the copy_to_user and
copy_from_user functions to see how they access a process address space from
kernel space.  That will probably start you in the right direction.
hope that helps!
Neil :)

Thank you for the answer.

I have not accessed the user  space directly.
Instead I have just used copy_from_user():


int
sys_sigsuspend(old_sigset_t mask, int p2, int p3, int p4, int p6, int
p7,
	       struct pt_regs *regs)
{
  ...
  while (1) {

    current->state = TASK_INTERRUPTIBLE;

    current->in_suspend = 1;     /* XXX my stuff for debugging */
    current->user_regs  = regs;
    if(copy_from_user(current->user_stack_xxx, regs->gpr[1], 128)){

      printk("\n------------- copy_from_user failed: %d\n", ret);
    }

    schedule();

    current->in_suspend = 0;    /* XXX my stuff for debugging */
    current->user_regs  = NULL;
    ...
}

The copy_from_user() works fine. The printk() message does not
appear.

Later, when I inspect 'current->user_stack_xxx' (temporary
added to struct_task) for all processes with 'current->in_suspend'
set, all seems to be zero. I do this check within a kernel
module, I can load when the threads are hanging.

Steffen

--


--------------------------------------------------------------

Steffen Rumler
ICN ON PNE SB 4
Siemens AG
Hofmannstr. 51                 Email: Steffen.Rumler@icn.siemens.de
D-81359 Munich                 Phone: +49 89 722-44061
Germany                        Fax  : +49 89 722-36703

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