Very Computer

I'm writing a module (for 2.2) which starts a kernel thread at insmod time.
I have run into two problems.  The first is that my thread is a child of
insmod unless I start it from outside process context.  Currently I work
around that by launching it from a kernel timer which expires momentarily
after insmod.  The other problem is that when my thread functions exits, it
becomes a zombie.  Is there a way for me to cleanly remove the thread at
rmmod time when it is finished doing it's work?

thanks,
-bp
--

Software Engineer, WGT Inc.     . http://www.terran.org/~bryan

exit_files(current) ;               /* close all files */
exit_mm(current) ;                  /* detach user pages */
current->pgrp = 1 ;                 /* detach from parent */
current->session = 1 ;              /* now owned by "init" */
current->uid = 0 ;                  /* become root */
current->euid = 0 ;                 /* become root */
current->tty = NULL ;               /* detach from any tty */
current->mm->arg_start = current->mm->arg_end = 0;
strcpy(current->comm, "MyProc") ;   /* set my display name (short string) */

Make sure the string "MyProc" is fairly short.  This will be the display name
of your process in a ps.  It will be enclosed in ()'s.

Have the parent remember the process id somewhere in your driver.

Then when  you want to kill off your process do this (assume process id is in
"my_pid"):

if (my_pid > 0)            /* Only stop the kernel thread if running */
    kill_proc(my_pid, SIGINT, 1) ;

Make sure that any waits that you do in the process are interruptible.

-- Dave

I did all that you said and it made no difference; after the kill_proc, the
thread wakes from interruptible_sleep_on, then does a MOD_DEC_USE_COUNT,
and return 0.  I still end up with a zombie thread.  I am starting this
thread from a kernel timer; is there any way for this to work?

% ps lw 32694
 FLAGS   UID   PID  PPID PRI  NI   SIZE   RSS WCHAN       STA TTY TIME COMMAND
    44     0 32694     0  20  20      0     0  3277c4     Z N ?   0:00
(thread-test <zombie>)

thanks,
-bp
--

Software Engineer, WGT Inc.     . http://www.terran.org/~bryan

Correction, you can start them!  I just can't seem to stop them. :(  I have
a small module which does a kernel_thread from the function of a kernel
timer, and it works no problem.  But when the thread dies/returns, it
becomes a zombie.

Any ideas?

thanks,
-bp
--

Software Engineer, WGT Inc.     . http://www.terran.org/~bryan