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.