Patch Name:  PHKL_1556

Patch Description: Diskless systems get panic "Kernel DMEM protection fault"
        in KI code.

   Symptoms:
   Diskless systems panic with "Kernel DMEM protection fault" message on
   console.  The pcsq.pcoq value in the panic message points to
   ki_dm1_send+0x90.  This can be checked using adb.  As an example if the
   the console message says pcsq.pcoq = 0.10ea2c, entering this command:

   adb /hp-ux /dev/kmem
      then typing:
   0x10ea2c/i
      will give:
   ki_dm1_send+90: stw     arg1,0(arg3)

   KI stands for Kernel Instrumentation.  The chances of this problem
   occuring become more likely as the number of cnodes increases.

   Fix:
   The problem was that the KI code was looking at a mbuf after it had been
   freed.  If an interrupt happens and the mbuf gets reallocated
   between the time the mbuf was freed and when the KI code looks at it,
   the bus error could occur or at best KI would get the wrong information.
   The fix was to have KI look at the mbuf before it was freed.

Path Name:  /hp-ux_patches/s700/8.X/PHKL_1556

Effective Date:  920925

Patch Files:  /system/PHKL_1556/new/conf/dm.o

SR/APR#:  5003022830

"what" string/timestamp:  
dm.o:
         PATCH_8.07:   dm.o     1.9.61.2    92/09/25 PHKL_1556

"sum" output:  
33531 16 dm.o

Dependencies:  None.

Supersedes: None.

Patch Package Size:  41 Kbytes

Installation Instructions:  

     Please review all instructions and the Hewlett-Packard
     SupportLine User Guide or your Hewlett-Packard support terms
     and conditions for precautions, scope of license,
     restrictions, and, limitation of liability and warranties,
     before installing this patch.

     Note: Please back up your system before you patch.

---------------------------------------------------------------------------
After getting the patch onto your machine, unshar the patch (sh PHKL_1556).

To install this patch do the following:
1) Run /etc/update (Note: you must be logged in as root to update
   a system).
2) Once in the update "Main Menu" move the highlighted line to "Change
   Source or Destination ->" and press "Return" or "Select Item".
3) Make sure the highlighted item in the "Change Source or Destination"
   window is "From Tape Device to Local System ...", then press "Return" or
   "Select Item".
4) You should now be in the "From Tape Device to Local System" window.
   Change the "Source:  /dev/rmt/0m" to "Source: /tmp/PHKL_1556.updt"
   (this assumes that you are in the /tmp directory where PHKL_1556.updt
   has been placed).  Note: You must enter the complete path name.
5) Press "Done".
6) From here on follow the standard directions for update.

The customized script that update runs will move the original software
to /system/PHKL_1556/orig.  HP recommends keeping this software there in
order to recover from any potential problems.  It is also recommended that
you move the PHKL_1556.text file to /system/PHKL_1556 to be retained for
future reference.

If you wish to put this patch on a magnetic tape and update from the tape
drive, dd a copy of the patch to the tape drive.  As an example the
following will create a copy of the patch that update can read:
dd if=PHKL_1556.updt of=/dev/rmt/0m bs=2048