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- Sun Proprietary/Confidential: Internal Use Only -
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                            FIELD INFORMATION NOTICE
                  (For Authorized Distribution by SunService)

FIN #: I0840-1

Create Date: Jun/19/02

Keywords: 

Sun Fire Servers (3800/4800/4810/6800) may encounter panic during Dynamic Reconfiguration (DR) operation of PCI and cPCI I/O boards

SunAlert: Yes

Top FIN/FCO Report: Yes

Products Reference: DR on Sun Fire 3800/4800/4810/6800

Product Category: Server / Service

Product Affected: 

Systems Affected:
-----------------  
Mkt_ID   Platform   Model   Description          Serial Number
------   --------   -----   -----------          -------------
  -        S8         -     Sun Fire 3800              -
  -        S12        -     Sun Fire 4800              -
  -        S12i       -     Sun Fire 4810              -
  -        S24        -     Sun Fire 6800              -


X-Options Affected:
-------------------
Mkt_ID   Platform   Model   Description   Serial Number
------   --------   -----   -----------   -------------
  -         -         -          -              -

Parts Affected: 

Part Number   Description                         Model
-----------   -----------                         -----
540-4616-03   Assy PCI I/O Board Serengeti          -
540-4617-03   Assy cPCI I/O Board Serengeti         -

References: 

BugId:      4641546 - System panic while configuring cPCI board. 

Sun Alert:  43842

Issue Description: 

Sun Fire 3800/4800/4810/6800 servers containing both cPCI I/O boards
(540-4617-03) and PCI I/O boards (540-4616-03) may encounter a panic
during Dynamic Reconfiguration (DR) operations.  Systems running
Solaris 8 with Patch 108528-14 installed may panic when a DR of these
I/O boards is performed.  Impact to customers is expected to be low
since very few customers have both cPCI and PCI I/O boards and also
perform DR operations.

Use 'showrev -p | grep 108528' to check for the presence of Patch
108528-14.  'prtconf', 'prtdiag', or visual inspection will confirm
that both cPCI and PCI I/O boards are installed in a system.

The following is one sequence of DR operations that has been shown to
demonstrate this panic. There may be additional sequences that will
also expose the panic.                             

    . unconfigure cPCI card in I/O board
    . unconfigure I/O board
    . connect I/O board
    . Unconfigure/configure I/O board
    . # cfgadm -c configure N0.IB8                  

Solaris will panic in a "stack overflow" as shown by the panic string: 
   
    panic: ptl1 trap reason 0x2TL=0x1 TT=0x68 TICK=0x1c87ff5eb ...
    panic[cpu2]/thread=30002d64140: Kernel panic at trap level 2
    000000001040c1f0 unix:sys_tl1_panic+8 
    ...                              

The cause of this panic is as follows.  The ddi framework does a
bottom-up traversal of sibling nodes during I/O device configuration.
This may lead to a stack overflow (depending upon the current system
configuration and which drivers are attached/loaded).  The stack
overflow results in a panic.
   
A software fix is being tested and will be integrated into Solaris 8.
Until this fix is available, use the workaround provided below to avoid
this problem.

Implementation: 

---
        |   |   MANDATORY (Fully Proactive)
         ---    
         
  
         ---
        | X |   CONTROLLED PROACTIVE (per Sun Geo Plan) 
         --- 
         
                                
         ---
        |   |   REACTIVE (As Required)
         ---

Corrective Action: 

The following recommendation is provided as a guideline for authorized
Enterprise Services Field Representatives who may encounter the above
mentioned problem.

For Sun Fire 3800/4800/4810/6800 systems with both cPCI I/O boards
(540-4617-03) and PCI I/O boards (540-4616-03), with Patch 108528-14,
and using DR, add the following line to the /etc/system file:
   
   # set lwp_default_stksize=0x6000
   
A reboot is necessary for these changes to take effect.

Comments: 

Some layered software like Veritas Volume Manager/VXFS or EMC Powerpath
also use the "lwp_stk_size" variable.  Make sure there aren't duplicate
entries of the above variable in the /etc/system file.

============================================================================

Implementation Footnote: 

i)   In case of MANDATORY FINs, Enterprise Services will attempt to    
     contact all affected customers to recommend implementation of 
     the FIN. 
   
ii)  For CONTROLLED PROACTIVE FINs, Enterprise Services mission critical    
     support teams will recommend implementation of the FIN  (to their  
     respective accounts), at the convenience of the customer. 

iii) For REACTIVE FINs, Enterprise Services will implement the FIN as the   
     need arises.
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