LTTng » LTTng-tools

Commit used:
============
userspace: 56e676d (HEAD, origin/stable-0.7) Document: rculfhash destroy and resize side-effect in 0.7
ust      : 83e4321 (HEAD, origin/master, origin/HEAD) Fix: incorrect support for multi-context
tools    : 1274479 (HEAD, origin/master, origin/HEAD) Fix: check channel subbuf size against page size
bebltrace: 5bfcad9 (HEAD, origin/master, origin/HEAD) Fix: handling of empty streams

Problem Description:
====================
 * While our stability-test is running, consumerD segfault once in a while with the following
   gdb info:
      (gdb) bt
      #0  0x00007f79958c72fc in ustctl_flush_buffer (stream=0x63c4e0, producer_active=0) at ustctl.c:1425
      #1  0x000000000041c57b in lttng_ustconsumer_on_stream_hangup (stream=0x647590) at ust-consumer.c:1196
      #2  0x000000000040a5e9 in consumer_thread_data_poll (data=0x633d10) at consumer.c:2500
      #3  0x00007f799549f7b6 in start_thread () from /lib64/libpthread.so.0
      #4  0x00007f79951fac5d in clone () from /lib64/libc.so.6
      #5  0x0000000000000000 in ?? ()

  * This segfault happens very often (about each 10 minutes ).

Is problem reproducible ?
=========================
  * yes 

How to reproduce (if reproducible):
===================================
  * We got 4 users, each has a different set of trace actions to perform (ex: create session, enable-chanel, 
    enable-event, start session, stop session, etc). Once the set of action has been done, that user sleep 
    for a few second and repeat the same set of actions again.

    While running the above, we encounter this consumerD segfault issue.

Any other information:
======================
- Included in this bug report is the gdb printout + the "sessiond -vvv --verbose-consumer" printout.
  The time at which the segfault occured, was about 14:10 .