[RELEASE] LTTng-modules 2.11.9 and 2.12.6 (Linux kernel tracer)

From: Mathieu Desnoyers
Date: Fri May 14 2021 - 15:52:50 EST


Hi,

The 2.11.9 and 2.12.6 releases of the LTTng kernel tracer are the latest bug fix releases
of the 2.11 and 2.12 stable branches of the LTTng modules project.

There are a few minor bug fixes, but those are the noteworthy changes:

- Support for 5.12 Linux kernels,
- Support recent stable kernel branches 4.14, 4.19, 5.4,
- Support for newer Ubuntu 4.15, 5.4 and RHEL 8.2/8.3 kernels,
- Fix: increment buffer offset when failing to copy from user-space:

Upon failure to copy from user-space due to failing access ok check, the
ring buffer offset is not incremented, which could generate unreadable
traces because we don't account for the padding we write into the ring
buffer.

Note that this typically won't affect a common use-case of copying
strings from user-space, because unless mprotect is invoked within a
narrow race window (between user strlen and user strcpy), the strlen
will fail on access ok when calculating the space to reserve, which will
match what happens on strcpy.

Thanks,

Mathieu

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

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