Re: mbuff in 2.2.14 rtlinux-2.2

[shackle <shackle-at-cme.nist.gov>]

On Mon, 11 Sep 2000 11:13:19 -0400 (EDT), Ray said:

> 
>  
>  Folk
>  
>  This should only be a problem with rtlinux-2.0 or later.
>  
>  I've been running the EMC as a user rather than root for some time and
>  have found an interesting problem that crops up now and again.
>  
>  After exiting the EMC, mbuff seems to get captured by another
>  process.  Then when I start EMC again it seems to share mbuff and after
>  a few starts and stops it doesn't run properly at all.  The sysmptoms are
>  a very slow start of emc and there are big delays in the mouse functions
>  when using tkemc.
>  
>  In order to run as a user, one thing I had to do is:
>  
>  chmod a=rw /dev/mbuff
>  
>  It would appear from xosview that when this problem occurrs, mbuff is
>  causing my system to use 100% of the processor's power. (perhaps this is
>  related to the problem noted in a recent post by Jan)
>  
>  After this error has occurred I get this report from lsmod:
>  
>  Module                  Size  Used by 
>  mbuff                   5356   3 
>  
>  And when I run the EMC I get delayed responses from tkemc and the
>  following report from lsmod.
>  
>  Module                  Size  Used by
>  steppermod            152652   0  (unused)
>  rtl_fifo                7336   0  (unused)
>  rtl_posixio             6684   0  [rtl_fifo]
>  rtl_sched              36756   0  [steppermod]
>  rtl_time               14080   0  [steppermod rtl_posixio rtl_sched]
>  mbuff                   5356   7  [steppermod]          
>  
>  The only way I seem to be able to fix the problem is to reboot.  Any hints 
>  
>  Ray
>  
>  
>  
>  
>  


The next time this happens try some/all of the following.

It's a good idea to save any files your editing, exit the editor and run sync a
couple of times first since there is a fair chance we are going to hang the
system completely.

Run top to see which processs are  taking the most cpu time.

If the highest process on the list is not idle, top, or init.

Try killing it with killall


killall <processname>

If it doesn't disappear off the top list, try the same as root and/or try:

killall -9 <processname>
(Warning killing some system processes will hang your system)


Run ipcs  to see what shared memory segments and semaphores were left around

Use "ipcrm" to delete them.

ipcrm -shm <id>

ipdrm -sem <id>

Try removing the modules one at a time.

rmmod steppermod
rmmod mbuff
. . .
--Will



-- 
-------------------------------------------------
William Penn Shackleford III			shackle-at-nist.gov
National Institute of Standards & Technology	Tel:	(301) 975-4286
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