[lttng-dev] [RELEASE] LTTng-UST 2.10.7, 2.11.1, 2.12.0-rc2 (Linux user-space tracer)

Mathieu Desnoyers mathieu.desnoyers at efficios.com
Wed Mar 4 16:27:08 EST 2020


This announcement covers new releases in the two actively maintained
stable branches of the LTTng-UST project (2.10.7 and 2.11.1), as well as
the second release candidate for the 2.12 branch (2.12.0-rc2).

LTTng-UST, the Linux Trace Toolkit Next Generation Userspace Tracer,
is a low-overhead application tracer. The library "liblttng-ust" enables
tracing of applications and libraries.

* Noteworthy fixes:

All of these releases contain a fix which ensures the FD_CLOEXEC flag
is set for _all_ file descriptors received by lttng-ust over unix
socket. This fixes an issue where more file descriptors than expected
stay open over exec.

Fixes were introduced to please the address sanitizer (ASan) part of
clang-9. One documented out-of-bound access was done by jhash as an
"optimization" which was rightfully tripping ASan. Since this is
not a fast-path, the optimization was removed and we always use the
slower "valgrind-safe" code path. We also annotated the variables
emitted in the __tracepoints_ptrs to ensure ASan does not emit
redzones around those variables, which are means to be contiguous
within the section.

For the 2.10 and 2.11 branches, building with -fno-common is
enforced to prepare for the upcoming default behavior change
in gcc 10.

Please try it out, and as usual, feedback is welcome!



Project website: https://lttng.org
Documentation: https://lttng.org/docs
Download link: https://lttng.org/download

Mathieu Desnoyers
EfficiOS Inc.

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