[ECOS] Fw: infinite loop in cyg_thread_create() function

["Vijay Padiyar" <vijaypadiyar at hotmail dot com>]

Hi

We are still facing the problem with thread creation that we faced earlier.
We are calling cyg_thread_create() from inside a method inside a class:

It's as follows:

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

void Context::run()
{
..
..
#ifdef ECOS

    cyg_thread handle;
    cyg_handle_t handle1;

    cyg_thread_create(priority, (cyg_thread_entry_t
*)&contextStart,(cyg_addrword_t)this, tasknm, NULL, stackSize, &handle1,
                                                &handle);
..
..
#endif
..
}

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

'run()' is a method inside class 'Context'. Earlier we were defining a stack
as 'static char stack[STACKSIZE]' just above the cyg_thread_create() call
and passing '&stack[0]' as the argument. That was causing problems.

But I read that passing 'NULL' will cause the cyg_thread_create() function
to automatically allocate stack area on its own. But even with NULL, it
doesn't seem to be working. It gets stuck in the same infinite loop in
Cyg_thread::add_to_list() in thread.cxx, i.e. prev = NULL.

How do we overcome this problem?

Regards

Vijay


> Hi
>
> Just forwarding Aravind's reply to the mailing list.
>
> Regards
>
> Vijay
>
>
>
>
> > On Thu, 2004-10-28 at 19:55, Chandrashekhar Padiyar wrote:
> > > Hi Arvind
> > >
> > > You wrote about this problem on the eCos mailing list:
> > >
> >
>
> --------------------------------------------------------------------------
> ----
> > >
> > > > Thanks for ur kind reply
> > > > After debugging i found that problem is in following code fragment
in
> > > > file thread.cxx:
> > > >
> > > > Cyg_Thread::add_to_list( void )
> > > > - 127 {
> > > >  128     // Add thread to housekeeping list
> > > >  129     Cyg_Scheduler::lock();
> > > >  130
> > > > - 131     if( thread_list == 0 )
> > > >  132         list_next = this;
> > > >  133     else {prev != thread_list
> > > >  134         Cyg_Thread *prev = thread_list;
> > > > - 135         do {
> > > > - 136             if ( this == prev )
> > > >  137                 break; // found it already!
> > > > - 138             prev = prev->list_next;
> > > > - 139         } while ( prev != thread_list );
> > > > - 140         if ( this != prev ) {
> > > >  141             // insert it in the list:
> > > > - 142             list_next = thread_list->list_next;
> > > > - 143             thread_list->list_next = this;
> > > >  144         }
> > > >  145     }
> > > >
> > > > the control is in the while loop forever as prev == thread_list (
line
> > > > 139 )ie prev has become NULL.
> > >
> >
>
> --------------------------------------------------------------------------
> ----
> > >
> > > Well we are facing the EXACT SAME problem now. Please tell us more
about
> how you solved it. We are calling the cyg_thread_create() function from a
> function inside a class. It gets stuck the second time in the same while()
> loop.
> > >
> > > Please tell us how exactly you modified the stack allocation.
> > >
> > > This is our function call:
> > >
> >
>
> --------------------------------------------------------------------------
> ----
> > >
> > > static char tskstack[STACK_SIZE];        //Stack size is 5632 bytes
> > >
> > > cyg_thread_create(10, (cyg_thread_entry_t
> *)&contextStart,(cyg_addrword_t)this,
> tasknm,&tskstack[STACK_SIZE],STACK_SIZE, &id1,
> > >                                                 &id);
> > >
> >
>
> --------------------------------------------------------------------------
> ----
> > >
> > > Please help us out here.
> > >
> > > Regards
> > >
> > > Vijay
> > >
> > i think u have created single dimension array for "space to store the
> thread data" and "for
> > pointer to the stack base" . Looking at what you sent you created one
> > thread with its stack stack[0] and the other thread with its stack
> > stack[1]. try creating a seperate array for each thread.
> >
> > regards
> > Aravind B
> >
> >
> >
>


-- 
Before posting, please read the FAQ: http://ecos.sourceware.org/fom/ecos
and search the list archive: http://ecos.sourceware.org/ml/ecos-discuss