[RELEASE] LTTng modules 2.9.0-rc1 "JoannÃs" (Linux kernel tracer)

[Mathieu Desnoyers]

We are proud to announce release candidate 1 of LTTng-modules 2.9.0.
Please test it within the coming month, and let us know if anything
goes unexpectedly before we proceed to the final release.

The LTTng modules provide Linux kernel tracing capability to the LTTng
2.9 tracer toolset.

New and Noteworthy for 2.9.0-rc1:

* Various performance improvements. Tested on x86-64 and ARM32.
* Add bitfield, enumeration, variant, structure, compound
  array/sequence types.
* Add custom field support.
* IPv4, IPv6, and TCP header data is now traced with the net_.
  tracepoints.
* Implement select, pselect6, poll, ppoll, epoll_wait, epoll_pwait,
  epoll_ctl, detailed system call tracing.
* The accept4() system call payload detail is now traced on x86-64.
* New "i2c" instrumentation. We introduce the module parameter
  "extract_sensitive_payload" for this probe. It is disabled by
  default. When enabled, it allows tracing i2c payload information
  which may contain sensitive data (e.g. keystrokes).
* When lttng-modules gets built into the kernel image, select
  TRACEPOINTS rather than depending on it.

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

The 2.9 release "JoannÃs" is named after a Berliner Weisse style
beer from the TrÃfle Noir microbrewery in Rouyn-Noranda.

Changelog:

2016-10-07 (National Frappà Day) LTTng modules 2.9.0-rc1
        * Fix: i2c: support kernels < 3.15
        * Fix: show warning for broken clock work-around
        * Bump minor ABI version
        * Fix: work-around upstream Linux timekeeping bug
        * Add support for i2c tracepoints
        * Cleanup: makefile version checks with single "ge"
        * Performance: special-case NULL in lttng_strlen_user_inatomic
        * Fix: lttng_inline_memcpy does not take a __user argument
        * Performance: implement lttng_inline_memcpy
        * Performance: cache the backend pages pointer in context
        * Cleanup: libringbuffer: remove duplicate pointer chasing in slow paths
        * Performance: Only dereference commit index once
        * Performance: Mark channel and buffer event disabled check unlikely
        * Performance: Relax atomicity constraints for crash handling
        * Performance: mark ring buffer do_copy callers always inline
        * Performance: mark lib_ring_buffer_write always inline
        * Kconfig: select TRACEPOINTS when built-in
        * Performance: disable event counting by default
        * Fix: handle large number of pages or subbuffers per buffer
        * Fix: unregister cpu hotplug notifier on buffer alloc error
        * Fix: sa_family is of type unsigned short
        * Fix: check for sizeof sa_family to save sa_family in accept and connect
        * Fix: use printk_once() for wrapper warning messages
        * Fix: btrfs instrumentation for 4.8 kernel
        * Fix: update mm_vmscan instrumentation for kernel 4.8
        * Fix: napi instrumentation for 4.8 kernels
        * Fix: update block instrumentation to compile on 4.8 kernels
        * Cleanup: reuse code in accept() and accept4() instrumentation
        * Add x86-64 override for accept4 syscall
        * Fix: timer wrapper: support kernels >= 4.8
        * Performance: split check deliver fast/slow paths
        * Fix: x86-64 accept instrumentation
        * Fix: Add support for 4.6.4-rt8 kernel
        * Fix: update scsi instrumentation for 4.7+ kernels
        * Fix: Use fs_initcall instead of rootfs_initcall
        * Fix: Add kernel configuration for lttng clock plugin
        * Fix: the clock plugin must be initiated before first use of the clock
        * Fix: tests/Kbuild for older kernels
        * Cleanup: __dynamic_len_idx set but not used warning
        * Cleanup: coding style and comments of net.h
        * net: Add TCP header data to net_* tracepoints
        * net: Add IPv4/IPv6 header data to net_* tracepoints
        * Fix: endianness for the container type of enum
        * enumeration autoincrement: use if/else logic
        * Cleanup trailing whitespaces
        * lttng-test probe: test ctf_enum_auto()
        * Add ctf_enum_auto() for autoincrementing enumeration values
        * Implement session statedump command
        * Fix: annotate bytecode interpreter for kernel stack validator
        * Update version to 2.9.0-pre
        * Fix: ring buffer: honor switch parameter type in remote switch
        * Fix: only flush non-metadata channels
        * Fix: don't perform extra flush on metadata channel
        * select, poll and epoll_wait overrides on ARM 32-bit
        * Fix: flush empty packets on snapshot channel
        * Fix: do not generate packet at destroy after stop
        * Fix: compat ioctl for flush/get metadata version
        * Fix: ctf_string() should handle NULL pointers
        * Fix: portability: no arith on void pointer
        * Fix: add missing tests/Kbuild
        * Test clock override plugin
        * Fix: add modules target to base Makefile
        * Fix: make clean does not include dot-config
        * Fix: trigger build error if CONFIG_TRACEPOINTS is not set
        * Documentation: document that CONFIG_MODULES not required when builtin
        * Fix: add missing errno include in random wrapper
        * Fix: mm_page_alloc_extfrag instrumentation for kernel 3.16.35
        * Fix: copy_from_user size when limited allocation
        * Extract the payload of epoll_wait/epoll_pwait
        * Extract the payload for epoll_ctl
        * Extract the FDs and flags from poll and ppoll
        * Extract the FD sets in select and pselect6
        * Add ctf_integer_bitfield_type
        * Implement enumeration type
        * Implement custom field support
        * Implement variant type
        * Implement shadow stack for dynamic len
        * libringbuffer: implement event too big API
        * Implement structure, compound array/sequence types
        * Fix: integer endianness metadata generation
        * Fix: endianness of integers received by filter
        * Fix: writeback probe on RHEL >= 3.10.0-327.10.1
        * Fix: RHEL kernel 3.10.0-327.13.1 compat
        * Fix: ctf_user_integer should not trigger page fault
        * Fix: lib_ring_buffer_copy_from_user_inatomic error handling
        * Add comment describing ioctl number duplication
        * Fix: remove unused gfpflags.h from btrfs and compaction instrumentation
        * Fix: Remove dead code from filter interpreter
        * Fix: x86 kvm mmutrace instrumentation for kernel < 3.6
        * Fix: mm_vmscan instrumentation: remove unused gfpflags.h include
        * Fix: use of uninitialized ret value in lttng_abi_create_event
        * Fix: kmem instrumentation: remove unused gfpflags.h include
        * Fix: 4.6 kernel: use in_compat_syscall
        * Fix: use BUG_ON instead of accessing array subscript above array bounds
        * Fix: Add granularity to RHEL kernel version checks

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