topic Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken in Operating System - OpenVMS

Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Larry McGhaw — Thu, 09 Apr 2009 15:04:00 GMT

I have a customer getting this crash:

Does anyone know what NOTFCBFCB means?

SDA> show crash
System crash information
------------------------
Time of system crash: 16-MAR-2009 16:40:14.67

Version of system: OpenVMS (TM) VAX Version V5.5-2H4

System Version Major ID/Minor ID: 1/0

VAXcluster node: CRDEV2, a VAX 4000-700A

Crash CPU ID/Primary CPU ID: 00/00

Bitmask of CPUs active/available: 00000001/00000001

CPU bugcheck codes:
CPU 00 -- NOTFCBFCB, FCB linkage broken

Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Duncan Morris — Thu, 09 Apr 2009 15:20:58 GMT

Larry,

how up to date are the patches on this system?

See

http://ftp.support.compaq.com.au/pub/patches/Readmes/vms/vaxy2k01_u2055.README

for references to fixes in VAXF11X02_U2055 KIT

The net result is any number of different XQP bugchecks, most
notably UNXSIGNAL (ACCVIO), NOTFCBFCB, and XQPERRs.

This seems to be relatively easy to provoke if you back up the
same disk in two different processes at the same time.

A modification was made earlier to the XQP to fix this lack of
synchronization; however, this fix had a timing window in it.

Duncan

Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Larry McGhaw — Thu, 09 Apr 2009 15:30:01 GMT

Thanks for the very fast response.

According to the crash data, the customer is at V5.5-2H4.

And the patch info you provided states:

Kit Applies To: OpenVMS VAX V5.5-2, V5.5-2H4, V5.5-2HF

So I'm fairly confident that this will fix the issue.

Thanks again.

lm

Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Volker Halle — Thu, 09 Apr 2009 15:37:13 GMT

Larry,

this is an OpenVMS Files-11 XQP inline bugcheck. A routine was being passed a data structure, which should have been a FCB (File Control Block). As a consistency check, the type of the data structure was being verified and it was NOT a FCB (DYN$C_FCB), so a fatal NOTFCBFCB bugcheck was declared. This type of crash can happend due to pool corruption.

Make sure you have the most recent F11X patch installed. For V5.5-2H4, this would be F11BXQP.EXE linked 1-DEC-1999 V5.5-2010 from VAXODS1_01_U2055. You can check the version with

$ ANAL/IMA/INT SYS$LOADABLE_IMAGES:F11BXQP.EXE and looking at the Image Identification Information.

Please post the following information from the crash:

$ ANAL/CRASH dumpfile
SDA> READ/EXEC
SDA> EXA/INS @PC
SDA> EXA/INS @PC-20;30
SDA> EXIT

Volker.

Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Larry McGhaw — Thu, 09 Apr 2009 19:50:31 GMT

Here it is.

SDA> EXA/INS @PC
7FEE1371: MOVZBL 29(R2),R0
SDA> EXA/INS @PC-20;30
7FEE1351: BPT
7FEE1352: MTPR #08,#12
7FEE1355: MOVL @00(R4),R2
7FEE1359: CMPL R2,(R4)
7FEE135C: BNEQ 7FEE1361
7FEE135E: BRW 7FEE1437
7FEE1361: BLBC R3,7FEE1367
7FEE1364: BRW 7FEE143E
7FEE1367: CMPB 0A(R2),#07
7FEE136B: BEQL 7FEE1371
7FEE136D: BUGW #02B4
7FEE1371: MOVZBL 29(R2),R0
7FEE1375: ASHL #10,R0,R0
7FEE1379: MOVZWL 24(R2),R5
7FEE137D: ADDL2 R0,R5
7FEE1380: CMPL R5,04(AP)
7FEE1384: BNEQ 7FEE1393
SDA>

Re: Crash on VAX/VMS 5.5 - NOTFCBFCB, FCB linkage broken

Volker Halle — Fri, 10 Apr 2009 06:08:13 GMT

Larry,

I'm sorry, but I may have to disappoint you !

First of all, it is most likely, that the customer HAS already installed the Y2K patch !

Secondly, this crash is nearly ALWAYS caused by pool corruption. You can easily verify this:

R2 should be pointing to the 'bad' FCB:

$ ANAL/CRASH
SDA> READ SYS$SYSTEM:SYSDEF
SDA> EXA @R2;10
SDA> FORMAT/TYPE=FCB @R2

The byte at 0A(R2) should be 0x07 = DYN$C_FCB, but it will some other value, therefore the NOTFCBFCB crash is taken.

Further analysis of the dump would be needed to try to find a possible reason for nonpaged pool corruption. Make sure, you have the most recent (for V5.5-2H4) patches installed for products like UCX and or DECnet/DECnet-OSI, these tend to sometime cause pool corruption.

Feel free to post the results of the above SDA commands, maybe best in an attached .TXT file.

Has this crash been seen before on that system ? Anything 'unusual' happening at the time of crash ?

Volker.