IBM Support

IT31883: IBM MQ controller process (amqzxma0) stopped due to SIGSEGV after failing to allocate a shared memory set.

Subscribe to this APAR

By subscribing, you receive periodic emails alerting you to the status of the APAR, along with a link to the fix after it becomes available. You can track this item individually or track all items by product.

Notify me when this APAR changes.

Notify me when an APAR for this component changes.

 

APAR status

  • Closed as program error.

Error description

  • The IBM MQ controller process (amqzxma0) failed to create a
    shared
    memory segment.  The reported failure data capture (FDC) record
    is attached below:
    .
    | Probe Id          :- XY132002
                  |
    | Component         :- xstCreateExtent
    | Program Name      :- amqzxma0
    Major Errorcode   :- xecF_E_UNEXPECTED_SYSTEM_RC
                 |
                                 |
    | Probe Description :- AMQ6119: An internal IBM MQ error has
    occurred (Failed |
    |   to get memory segment: shmget(0x00000000, 268435456) [rc=-1
    errno=28] No  |
    |   space left on device)                        |
    | Comment2          :- No space left on device
    .
    
    the amqzxma0 process then generated an FDC with ZF037002
    zfu_in_init .
    .
    | Probe Id          :- ZF037002
    | Component         :- zfu_in_init
    .
    Finally, the amqzxma0 process reported an FDC file with XC130004
    SIGSEGV and aborted.
    
    | Probe Id          :- XC130004
                  |
    | Application Name  :- MQM
                  |
    | Component         :- xehExceptionHandler
    | Program Name      :- amqzxma0
    
    | Major Errorcode   :- STOP
                  |
    | Minor Errorcode   :- OK
                  |
    | Probe Type        :- HALT6109
                  |
    | Probe Severity    :- 1
                  |
    | Probe Description :- AMQ6109: An internal IBM MQ error has
    occurred.
    Arith1            :- 11 (0xb)
                 |
    | Comment1          :- SIGSEGV: invalid address
    permissions(0x7f0e1c074944)
    
    
    MQM Function Stack
    amqzxma0
    zxcExecutionController
    zxcCreateECResources
    zxcStartAllPlugServices
    zfp_ss_start_service_global
    zfp_ss_add_component
    zfu_in_init
    xcsQueryValueForSubpool
    xcsFFST
    

Local fix

  • This problem occurs when shared memory resources are running
    low.  A workaround for the problem is to fix the underlying
    reason for shared memory being unavailable to MQ.
    

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Users of systems which are low on shared memory resources may be
    affected by this problem
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    IBM MQ was unable to create a shared memory set and this caused
    an error path to be taken.  This error path attempted to use a
    variable which had not been initialised and a SEGV FDC was
    generated.
    

Problem conclusion

  • The error path was corrected so that IBM MQ does not access the
    uninitialised variable in the event of an error allocating a
    shared memory set.
    
    While the SIGSEGV will no longer be encountered on this error
    path, failures to allocate shared memory are likely to be
    detrimental to the normal operation of the queue manager and
    should be investigated by the system administrator if reported.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.0 LTS   9.0.0.11
    v9.1 LTS   9.1.0.7
    v9.2 LTS   9.2.0.2
    v9.x CD    9.2.1
    
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037
    
    If the maintenance level is not yet available information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'
    http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT31883

  • Reported component name

    IBM MQ BASE M/P

  • Reported component ID

    5724H7261

  • Reported release

    900

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-02-17

  • Closed date

    2020-10-13

  • Last modified date

    2020-11-18

  • APAR is sysrouted FROM one or more of the following:

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    IBM MQ BASE M/P

  • Fixed component ID

    5724H7261

Applicable component levels

[{"Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0"}]

Document Information

Modified date:
19 November 2020