Critical Sectioning error when attempting to take a Coredump.

(Last modified: 11Oct2005)

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symptom

fact

Novell NetWare 6.5 SP3

Novell NetWare 6.5

symptom

The server abends and "Critical Sectioning" error message is on screen. Server hangs and after
going into the Debugger any attempts to retrieve a coredump result in the same error.

change

Updated to Netware 6.5 or applied support pack SP3 or later.

cause

FATFS.NLM handles accesses file system to the local FAT volumes which, prior to NetWare 6 were handled by the DOS which launched the NetWare server.exe. A side effect of incorporating access to the FAT file system into NetWare is that these accesses no longer appear as a single atomic operation to NetWare. Indeed it is possible for an Abend to occur while a FAT file system request is being processed, either in the context of that request, or simply concurrent with it (and unrelated.)

FATFS.NLM is able to do FAT file system I/O at debug time as well as process time. This is mainly because NetWare has always taken advantage of the fact that DOS's state was separate from NetWare's state and it was about as easy to write a file (via DOS) at debug time as at process time. Since FATFS.NLM operates within NetWare (it being a "normal NLM"), care must be taken to protect it from being used both at process time as well as at debug time. Certain areas of FATFS.NLM are enabled to be called at debug time while it is also being used at process time, but other areas are not so enabled. To protect these areas, FATFS.NLM implements a critical section lock to prevent access to these areas of FATFS at debug time. This protection has as a main goal protecting the data stored within the FAT file system so that corruption will not occur.

If your seeing the "ERROR: Critical sectioning prevents requested FATFS operation" message, it is due to the fact that FATFS is in such a context when an Abend occurred. NetWare attempts to write an abend.log file when an Abend occurs. Additionally, attempts to write a coredump file may result in the same message.

As mentioned above, the Abend is not necessarily directly related to FAT file system I/O if this message is produced.

fix

Set abend recovery to zero (0). This will halt the server at the first abend.
Copy the coredump to a remote server - TID 2968836 explains the dump procedure and has a link to the remote debugging tool.

note

Still under investigation.

document

Document Title:	Critical Sectioning error when attempting to take a Coredump.
Document ID:	10099285
Solution ID:	NOVL103835
Creation Date:	11Oct2005
Modified Date:	11Oct2005
Novell Product Class:	Netware

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