Re: A patch for the file kernel/fork.c

[André Pereira de Almeida <andre@cachola.com.br>]

Chris Wedgwood wrote:

> On Wed, May 04, 2005 at 11:46:18AM -0300, Andr? Pereira de Almeida wrote:
>
>  
>
> > -       if (tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
> > +       if (mm && tsk->clear_child_tid && atomic_read(&mm->mm_users) > 1) {
> >    
>
> did you actually see a problem here?
> -
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>  
In a preemptible kernel with the serport module and a serial port try to 
run the following program:

int main(int argc, char **argv)
{
       int ldisc,fd;

       fd = open("/dev/ttyS0", O_RDWR | O_NOCTTY | O_NONBLOCK);
       ldisc = N_MOUSE;
       ioctl(fd, TIOCSETD, &ldisc);
       read(fd, NULL, 0);
       return 0;
}

and kill it.
In my case it will hang the computer. I think this is a problem with the 
serport module. With this patch, the serial mouse stop working, but the 
computer don't hang.

-
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