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IT31676: BIPMQTT CAN CRASH WITH A SEGFAULT DURING HEAVY TRAFFIC SCENARIOS

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APAR status

  • Closed as program error.

Error description

  • The bipMQTT process can crash with a segmentation fault when
    experiencing heavy traffic. Very few diagnostics will be
    generated, for example no abend file will be created and a core
    dump will not necessarily be generated. If a core dump is
    generated the following stack may be seen:
    
    
    
    #0
    0x0000000000412496 in _mosquitto_read_uint16 (packet=0x24da5a8,
    word=0x7fff929dad7a) at
    /usr/local/src/mosquitto/lib/net_mosq.c:637
    
    #1
    0x000000000041230f in _mosquitto_read_string (packet=0x24da5a8,
    str=0x7fff929dadd0) at
    /usr/local/src/mosquitto/lib/net_mosq.c:606
    
    #2
    0x000000000041314c in mqtt3_handle_publish (db=0x625ca0,
    context=0x24da560) at
    /usr/local/src/mosquitto/src/read_handle.c:104
    
    #3
    0x000000000041301e in mqtt3_packet_handle (db=0x625ca0,
    context=0x24da560) at
    /usr/local/src/mosquitto/src/read_handle.c:48
    
    #4
    0x0000000000412e55 in _mosquitto_packet_read (db=0x625ca0,
    mosq=0x24da560) at
    /usr/local/src/mosquitto/lib/net_mosq.c:1021
    
    #5
    0x000000000040f109 in loop_handle_reads_writes (db=0x625ca0,
    pollfds=0x24da2f0) at
    /usr/local/src/mosquitto/src/loop.c:472
    
    #6 0x000000000040e94a
    in mosquitto_main_loop (db=0x625ca0, listensock=0x24d8550,
    listensock_count=2, listener_max=4) at
    /usr/local/src/mosquitto/src/loop.c:292
    
    #7 0x000000000040fd4c
    in main (argc=1, argv=0x7fff929db838) at
    /usr/local/src/mosquitto/src/mosquitto.c:366
    
    
    
    Though it is
    not guaranteed that the back trace will be readable.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    All users of IBM Integration Bus v10 and App Connect Enterprise
    v11 who use bipMQTT as an MQTT broker for production data.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    The bipMQTT process can crash with a segmentation fault when
    experiencing heavy traffic. Very few diagnostics will be
    generated, for example no abend file will be created and a core
    dump will not necessarily be generated. If a core dump is
    generated the following stack may be seen:
    
    #0 0x0000000000412496 in _mosquitto_read_uint16
    (packet=0x24da5a8, word=0x7fff929dad7a) at
    /usr/local/src/mosquitto/lib/net_mosq.c:637
    #1 0x000000000041230f in _mosquitto_read_string
    (packet=0x24da5a8, str=0x7fff929dadd0) at
    /usr/local/src/mosquitto/lib/net_mosq.c:606
    #2 0x000000000041314c in mqtt3_handle_publish (db=0x625ca0,
    context=0x24da560) at
    /usr/local/src/mosquitto/src/read_handle.c:104
    #3 0x000000000041301e in mqtt3_packet_handle (db=0x625ca0,
    context=0x24da560) at
    /usr/local/src/mosquitto/src/read_handle.c:48
    #4 0x0000000000412e55 in _mosquitto_packet_read (db=0x625ca0,
    mosq=0x24da560) at /usr/local/src/mosquitto/lib/net_mosq.c:1021
    #5 0x000000000040f109 in loop_handle_reads_writes (db=0x625ca0,
    pollfds=0x24da2f0) at /usr/local/src/mosquitto/src/loop.c:472
    #6 0x000000000040e94a in mosquitto_main_loop (db=0x625ca0,
    listensock=0x24d8550, listensock_count=2, listener_max=4) at
    /usr/local/src/mosquitto/src/loop.c:292
    #7 0x000000000040fd4c in main (argc=1, argv=0x7fff929db838) at
    /usr/local/src/mosquitto/src/mosquitto.c:366
    
    Though it is not guaranteed that the back trace will be
    readable.
    
    This is Mosquitto bug 463241 -
    https://bugs.eclipse.org/bugs/show_bug.cgi?id=463241
    

Problem conclusion

  • The product has been updated to use mosquitto 1.6.8 for bipMQTT
    which is not susceptible to this issue. Additionally the
    stdout/stderr for the bipMQTT process will now be written to the
    decidated file <WORKPATH>/components/<BROKER>/bipMQTT.txt on
    v10. Previously this output would be discarded on Windows and
    written to the stdout/stderr file for the bipbroker process on
    other platforms. The stdout/stderr for bipMQTT continues to be
    written to <WORKPATH>/components/<BROKER>/bipMQTT.stdout and
    <WORKPATH>/components/<BROKER>/bipMQTT.stderr respectively.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v10.0      10.0.0.21
    v11.0      11.0.0.9
    
    The latest available maintenance can be obtained from:
    http://www-01.ibm.com/support/docview.wss?rs=849&uid=swg27006041
    
    If the maintenance level is not yet available,information on
    its planned availability can be found on:
    http://www-1.ibm.com/support/docview.wss?rs=849&uid=swg27006308
    ---------------------------------------------------------------
    

Temporary fix

Comments

APAR Information

  • APAR number

    IT31676

  • Reported component name

    INTEGRATION BUS

  • Reported component ID

    5724J0540

  • Reported release

    A00

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-01-28

  • Closed date

    2020-05-26

  • Last modified date

    2020-05-26

  • 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

    INTEGRATION BUS

  • Fixed component ID

    5724J0540

Applicable component levels

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSNQK6","label":"IBM Integration Bus"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Line of Business":{"code":"LOB36","label":"IBM Automation"}}]

Document Information

Modified date:
27 May 2020