[RELEASE] LTTng UST 2.12.8/2.13.6 and LTTng modules 2.12.14/2.13.10 tracers

[Mathieu Desnoyers]

Hi,

This is a stable release announcement for the LTTng UST and LTTng modules tracer projects.
Those contain mainly bug fixes and add support for recent distributions and upstream kernels.

What's new in both LTTng-UST 2.12.8 and 2.13.6:

- Fix: use unaligned pointer accesses for lttng_inline_memcpy
    
  lttng_inline_memcpy receives pointers which can be unaligned. This
  causes issues (traps) specifically on arm 32-bit with 8-byte strings
  (including \0).

- Fix: trace events in C constructors/destructors

  Adding a priority (150) to the tracepoint and tracepoint provider
  constructors/destructors ensures that we trace tracepoints located
  within C constructors/destructors with a higher priority value,
  including the default init priority of 65535, when the tracepoint vs
  tracepoint definition vs tracepoint probe provider are in different
  compile units (and in various link order one compared to another).

- Fix: Reevaluate LTTNG_UST_TRACEPOINT_DEFINE each time tracepoint.h is included

  Fix issues with missing symbols in use-cases where tracef.h is included
  before defining LTTNG_UST_TRACEPOINT_DEFINE

- Fix: segmentation fault on filter interpretation in "switch" mode

  Fix a bytecode interpreter crash when building with INTERPRETER_USE_SWITCH
  defined (used mainly for debugging purposes).


What's new specifically in LTTng-UST 2.13.6:

- Fix: `ip` context is expressed as a base-10 field

  The base for UST context field `ip` was changed from 16 (hexadecimal) to
  10 (decimal), most likely an unintentional copy&paste error in 4e48b5d.

- Various fixes to build with -std=c99.

- Fix: trace events in C++ constructors/destructors

  Wrap constructor and destructor functions to invoke them as functions with
  the constructor/destructor GNU C attributes, which ensures that those
  constructors/destructors are ordered before/after C++
  constructors/destructors.


What's new in LTTng modules 2.12.14 and 2.13.10:

- fix: kallsyms wrapper on CONFIG_PPC64_ELF_ABI_V1

  Work-around PPC64 ELF ABI v1 function descriptor issues when using kallsyms.

- Add support for RHEL 9.0 and 9.1.


What's new specifically in LTTng modules 2.12.14:

- Various tracepoint instrumentation fixes to support kernel v5.18.


What's new specifically in LTTng modules 2.13.10:

- Various tracepoint instrumentation fixes to support kernel v6.3.


Feedback is welcome!

Thanks,

Mathieu

--
Mathieu Desnoyers
EfficiOS Inc.
https://www.efficios.com