Fix: check for sizeof sa_family to save sa_family in accept and connect

The check of addrlen >= sizeof(struct sockaddr) is too restrictive
and causes sa_family to not be saved in the case of AF_UNIX sockets
as the addrlen returned by the syscall may be only sizeof(short).

Individual checks per socket family are performed anyhow in the
switch case, making this safe.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: reuse code in accept() and accept4() instrumentation

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add x86-64 override for accept4 syscall

This patch adds an instrumentation override for the accept4() syscall
which is almost identical to accept(), except for an additional
"flags" parameter.

A follow-up patch refactors both overrides to minimize code
duplication as is done for the select/pselect6 overrides.

Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use printk_once() for wrapper warning messages

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: btrfs instrumentation for 4.8 kernel

Note: there are missing events.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update mm_vmscan instrumentation for kernel 4.8

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: napi instrumentation for 4.8 kernels

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update block instrumentation to compile on 4.8 kernels

These 2 upstream Linux commits break the block instrumentation in lttng
modules master:

https://github.com/torvalds/linux/commit/4e1b2d52a80d79296a5d899d73249748dea71a53

https://github.com/torvalds/linux/commit/288dab8a35a0bde426a09870943c8d3ee3a50dab

The errors are :

lttng-modules/probes/../instrumentation/events/lttng-module/block.h:35:13:
error: ‘REQ_DISCARD’ undeclared (first use in this function)

lttng-modules/probes/../instrumentation/events/lttng-module/block.h:41:14:
error: ‘REQ_SECURE’ undeclared (first use in this function)

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: timer wrapper: support kernels >= 4.8

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: x86-64 accept instrumentation

The ipv4/ipv6 addr are output parameters.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add support for 4.6.4-rt8 kernel

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update scsi instrumentation for 4.7+ kernels

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Use fs_initcall instead of rootfs_initcall

The rootfs_initcall for drivers built as modules was only introduced in
kernel 3.14 by commit b46d0c46ccaa366a5bb8ac709fdf2bcaa76221fd. Use
fs_initcall instead which comes just before and exists in older kernels.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add kernel configuration for lttng clock plugin

Only one lttng clock plugin can be used when building the lttng-modules
in the kernel. To make it possible to use a custom clock plugin it must
be possible to unconfigure the test clock plugin

Signed-off-by: Anders Wallin <wallinux@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: the clock plugin must be initiated before first use of the clock

When building lttng inside the kernel the clock plugin must be initated
before the rest of the lttng code. Moved the module_init to
rootfs_initcall. The functionality will not change when built as a
module.

Signed-off-by: Anders Wallin <wallinux@gmail.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: tests/Kbuild for older kernels

Older kernels (e.g. 2.6.38.8) don't seem to handle subdirectory in the
same way as recent kernels (e.g. 4.6). As a result, building LTTng
out-of-tree within a kernel modified to have LTTng as a built-in addon
fails with CONFIG_LTTNG=m.

$ make all O=../kernel_builddir
.....
  CC [M]  lttng/probes/lttng-kprobes.o
  CC [M]  lttng/probes/lttng-kretprobes.o
  LD      lttng/tests/built-in.o
  CC [M]  lttng/tests/probes/lttng-test.o
Assembler messages:
Fatal error: can't create lttng/tests/probes/lttng-test.o: No such
file or directory
/media/awallin/sda1/home/awallin/src/lttng-test/linux-2.6/scripts/Makefile.build:264:
recipe for target 'lttng/tests/probes/lttng-test.o' failed
make[3]: *** [lttng/tests/probes/lttng-test.o] Error 2
/media/awallin/sda1/home/awallin/src/lttng-test/linux-2.6/scripts/Makefile.build:403:
recipe for target 'lttng/tests' failed
make[2]: *** [lttng/tests] Error 2
/media/awallin/sda1/home/awallin/src/lttng-test/linux-2.6/Makefile:946:
recipe for target 'lttng' failed
make[1]: *** [lttng] Error 2
make[1]: Leaving directory
'/media/awallin/sda1/home/awallin/src/lttng-test/kernel_builddir'
Makefile:146: recipe for target 'sub-make' failed
make: *** [sub-make] Error 2

$tree ../kernel_builddir/lttng/tests/
../kernel_builddir/lttng/tests/
└── built-in.o

Reported-by: Anders Wallin <anders.wallin@windriver.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: annotate bytecode interpreter for kernel stack validator

With gcc 6.1.1, kernel 4.6, with
CONFIG_STACK_VALIDATION=y, building lttng-modules master
at commit 6c09dd94 gives this warning:

lttng-modules/lttng-filter-interpreter.o: warning: objtool:
lttng_filter_interpret_bytecode()+0x58: sibling call from
callable instruction with changed frame pointer

This object implements a bytecode interpreter using an explicit
jump table.

If we define "INTERPRETER_USE_SWITCH" at the top of the file,
thus using the switch-case fallback implementation, the
warning vanishes.

We use an explicit jump table rather than a switch case whenever
possible for performance reasons.

Unfortunately objtool doesn't know how to validate this type of jump
table. So to avoid the warning we need to add an annotation to tell
objtool to ignore it.

Kernel developers has to annotate __bpf_prog_run() in the kernel for the
same reason.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.8.0

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ring buffer: honor switch parameter type in remote switch

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: only flush non-metadata channels

Issue introduced by commit
"Fix: do not generate packet at destroy after stop".

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: don't perform extra flush on metadata channel

The metadata channel requires that the LTTng client layer and the ring
buffer keep a notion of the amount of data produced in the channel.

This issue has been introduced recently by commit
"Fix: flush empty packets on snapshot channel".

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: flush empty packets on snapshot channel

Snapshot operation on a non-stopped stream should use a "final" flush to
ensure empty packets are flushed, so we gather timestamps at the moment
where the snapshot is taken. This is important for streams that have a
low amount of activity.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: do not generate packet at destroy after stop

In the following scenario:
- create, enable events (kernel),
- start
- ...
- stop (await for data_pending to complete)
- destroy
- rm the trace directory

We would expect that the "rm" operation would not conflict with the
consumer daemon trying to output data into the trace files, since the
"stop" operation ensured that there was no data_pending.

However, the "destroy" operation currently generates an extra packet
after the data_pending check. This causes the consumer daemon to try to
perform trace file rotation concurrently with the trace directory
removal in the scenario above, which triggers errors. The main reason
why this empty packet is generated by "destroy" is to deal with trace
start/stop scenario which would otherwise generate a completely empty
stream.

Therefore, introduce the concept of a "quiescent stream". It is
initialized at false on stream creation (first packet is empty). When
tracing is started, it is set to false (for cases of start/stop/start).
When tracing is stopped, if the stream is not quiescent, perform a
"final" flush (which will generate an empty packet if the current packet
was empty), and set quiescent to true.  On "destroy" stream: if the
stream is not quiescent, perform a "final" flush, and set the quiescent
state to true.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: compat ioctl for flush/get metadata version

Unlike the non-compat version, the compat ioctl lttng ABI code for the
ring buffer flush operation does not invoke
lttng_metadata_output_channel before calling the ring buffer operation.
This could lead to incomplete metadata on 64-bit kernels running with
32-bit lttng userland.

There is also a discrepancy between the non-compat and compat code: the
GET_METADATA_VERSION operation is performed before calling the ring
buffer code. Ensure both non-compat and compat code are alike.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ctf_string() should handle NULL pointers

The regmap instrumentation can send a NULL string (e.g. on ARM32).

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: portability: no arith on void pointer

Reported by cppcheck.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing tests/Kbuild

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Test clock override plugin

Fixes: #939
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add modules target to base Makefile

This way running 'make modules' will indeed build the modules
like in the upstream build system.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: make clean does not include dot-config

Skip the CONFIG_TRACEPOINT test if dot-config has not been included.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: trigger build error if CONFIG_TRACEPOINTS is not set

Fixes: #1015
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Documentation: document that CONFIG_MODULES not required when builtin

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: mm_page_alloc_extfrag instrumentation for kernel 3.16.35

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: integer endianness metadata generation

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: endianness of integers received by filter

We need to byteswap integers passed to the filter when they are tagged
as being in an endianness which differs from the architecture
endianness, so the integer comparisons make sense in terms of value
rather than raw bytes for those fields.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.8.0-rc2

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: writeback probe on RHEL >= 3.10.0-327.10.1

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: RHEL kernel 3.10.0-327.13.1 compat

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: ctf_user_integer should not trigger page fault

It is not used by the instrumentation currently, but fix it
nevertheless.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: lib_ring_buffer_copy_from_user_inatomic error handling

It should treat nonzero return value of
lib_ring_buffer_do_copy_from_user_inatomic() as errors, 0 as success.

It is currently unused by the instrumentation.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add comment describing ioctl number duplication

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: remove unused gfpflags.h from btrfs and compaction instrumentation

Its content is unused, and this file disappears in Linux 4.6-rc.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Remove dead code from filter interpreter

Detected by Coverity:
** CID 1353794:  Control flow issues  (DEADCODE)
/lttng-filter-interpreter.c: 123 in stack_strcmp()

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: x86 kvm mmutrace instrumentation for kernel < 3.6

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: mm_vmscan instrumentation: remove unused gfpflags.h include

This header disappears in kernel 4.6, but we don't actually use it, so
remove its include.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use of uninitialized ret value in lttng_abi_create_event

Fixes the following compiler warning:

/home/jenkins/workspace/lttng-modules_VERSION_param-build/arch/x86-32/src/lttng-modules/lttng-abi.c: In function ‘lttng_abi_create_event’:
/home/jenkins/workspace/lttng-modules_VERSION_param-build/arch/x86-32/src/lttng-modules/lttng-abi.c:987:16: warning: ‘ret’ may be used uninitialized in this function [-Wmaybe-uninitialized]
  int event_fd, ret;

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: kmem instrumentation: remove unused gfpflags.h include

This header disappears in kernel 4.6, but we don't actually use it, so
remove its include.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: 4.6 kernel: use in_compat_syscall

in_compat_sycall appears in kernel 4.6. Use it instead of
is_compat_task(), but use is_compat_task() as fallback.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: use BUG_ON instead of accessing array subscript above array bounds

Building lttng-modules lttng-filter-interpreter.c on a 4.6-rc kernel
triggers the following gcc warning:

In file included from /home/compudj/git/lttng-modules/lttng-filter-interpreter.c:25:0:
/home/compudj/git/lttng-modules/lttng-filter-interpreter.c: In function ‘lttng_filter_interpret_bytecode’:
/home/compudj/git/lttng-modules/lttng-filter.h:144:14: warning: array subscript is above array bounds [-Warray-bounds]
   &(stack)->e[top];    \
              ^
/home/compudj/git/lttng-modules/lttng-filter-interpreter.c:714:4: note: in expansion of macro ‘estack_ax’
    estack_ax(stack, top)->u.s.str = insn->data;
    ^
/home/compudj/git/lttng-modules/lttng-filter.h:144:14: warning: array subscript is above array bounds [-Warray-bounds]
   &(stack)->e[top];    \
              ^
/home/compudj/git/lttng-modules/lttng-filter-interpreter.c:715:4: note: in expansion of macro ‘estack_ax’
    estack_ax(stack, top)->u.s.seq_len = UINT_MAX;

This is because the bound checking is performed in a prior validation
phase (which the compiler does not know about), and we only
WARN_ON_ONCE() if the interpreter sees values that don't fit in array
range.

Use BUG_ON() in the interpreter instead, which ensures we never, ever
reach the out-of-bound condition from a compiler perspective.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add granularity to RHEL kernel version checks

Our RHEL kernel version macros were based on the major and minor version
of the distribution version like "7.2" instead of the full kernel version
like "327.4.4". This prevented us from adding compatibility changes with
sufficient granularity.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Version 2.8.0-rc1

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Bump minor tracer ABI version

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: build against out-of-tree kernel build

Fix following system header include modifications.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

probes/Kbuild: remove upper level header path

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Move leftover relative include paths to system paths

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

syscall instrumentation: use system headers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

tracepoint event instrumentation: use system headers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include path in wrappers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

libs: use system include paths

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system header paths in core implementation files

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include paths in root directory headers

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include paths in probes

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update gitignore

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include paths in lttng-types.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include paths in lttng-tracepoint-event-impl.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include path in probes/define_trace.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Use system include paths in probes/lttng-tracepoint-event-impl.h

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Rename probes/lttng-events.h to probes/lttng-tracepoint-event-impl.h

Ensure we don't have a duplicated header file name in the tree.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add makefile directory to include path

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: event ctx get size should be after chan ctx

Match the record functions, and the CTF spec. This has no impact
currently because event contexts are not implemented.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: filter interpreter with userspace strings

The filter interpreter is populating the "str" register field, but the
string comparison functions expect to use the "user_str" register field
whenever it deals with a userspace string ("user" flag set to 1).

Since we are using __copy_from_user_inatomic(), this is typically
bailing out on anything that requires to read the string (except the '*'
wildcard).

Fixes #943

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: rename kvm x86 TRACE_SYSTEM to avoid name clash

The lttng-probe-kvm and lttng-probe-kvm-x86 have the same TRACE_SYSTEM
string. Because of that, both modules can't be loaded at the same time.
The second module fails to load silently. Rename the TRACE_SYSTEM of
lttng-probe-kvm-x86 to avoid the clash.

We need to use the LTTNG_TRACEPOINT_EVENT_MAP to perform this
namespacing while still hooking onto the kernel tracepoints.

Fixes #895

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: format address fields as hexadecimal

Fixes #947

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

PowerPC-64 ABIv1: add build error if KALLSYMS_ALL is missing

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: system call instrumentation overrides

* All architectures

- For mmap, print the "ret" value as an hexadecimal integer (rather than
  base 10), which better suits a pointer.
- Add missing "clone" override define, which ensures the clone
  system call override is used rather than leaving it as an
  "unknown" system call.

* ARM32

- Add missing output return values to arm_fadvise64_64,
  sync_file_range2.
- Handle the 64-bit parameters of both arm_fadvise64_64 and
  sync_file_range2 correctly on arm32, on big and little endian builds.
- Move the mmap2 system call instrumentation from "pointers" to
  "integers" override header, and add the missing return value
  (sc_exit).

* PPC32

- Add sync_file_range2 system call instrumentation. Handle the
  64-bit parameters on big and little endian builds.
- Move the mmap2 system call instrumentation from "pointers" to
  "integers" override header, and add the missing return value
  (sc_exit).

* PPC64 compat

- Include compatibility (ppc32) header in ppc64 build to trace compat
  system calls on PPC64 big endian.

* x86-32

- Add mmap2 system call instrumentation override.
- Add sync_file_range instrumentation override, correctly combining
  the low/high parts of offset and nbytes into 64-bit fields.

Tested-by: Jonathan Rajotte <jonathan.rajotte-julien@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: page_alloc wrapper incorrect parenthesis

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: system call tracing for arm-64 compat !CONFIG_UID16

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add struct user_msghdr forward declaration for older kernels

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Cleanup: Remove unused lttng-types module

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: add missing versions and init call for page_alloc wrapper

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Define lttng-tracer metadata only once

Fixes sysfs trying to create the lttng-tracer module version node
multiple times.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Add CONFIG_LTTNG to modules_install target

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Use kbuild env instead of a custom var KERNELDIR

We currently use the custom variables KERNELDIR and LTTNG_KERNELDIR
to pass the kernel source tree directory to helper scripts. We should
instead use the built-in Kbuild variable CURDIR which is available in
all sub makefiles and always points to the kernel sources.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Update clock offset comment

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

clock offset: print negative value in metadata

In the upcoming 2.8, we can print the negative value of clock offset in
the metadata, and expect users to update their viewers to correct any
bug that could prevent them from handling those negative values.

This happens only in cases where the system sets CLOCK_REALTIME to 0
after boot, thus leading to a negative clock offset value between
realtime and monotonic clocks.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: handle negative clock offset

In the unlikely situation where a system sets its hardware clock
(CLOCK_REALTIME) to 0 (Epoch) after boot, the difference

  monotonic - realtime

becomes negative.

Fixup this situation by returning a 0 offset in this case.

This ensures that trace viewer implementations (e.g. babeltrace) which
currently cannot handle the negative offset (known bug) still work with
the generated traces.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: sched instrumentation for 4.1-rt11

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add RT patch version macros

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Expect filter context identifiers starting with $ctx.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

ARM64: wire up compat system calls

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add support for arm64 syscalls

[ Edit by Mathieu Desnoyers: rename "x86_64" strings to "arm64" in
  comments. ]

Signed-off-by: Jan Willeke <jan.willeke@harman.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Ubuntu kernel range for block_rq_complete

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: Ubuntu kernel range for mm_page_alloc_extfrag

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: update vmscan instrumentation for kernel 4.5

The following tracepoint changes made their way into Linux 4.5-rc1:

commit 3aa2385111168187f24a6db04697c6fab0fab9b4
Author: yalin wang <yalin.wang2010@gmail.com>
Date:   Thu Jan 14 15:18:30 2016 -0800

    mm/vmscan.c: change trace_mm_vmscan_writepage() proto type

and

commit ba5e9579433aefcdccdec207601e124d3bdf2a71
Author: yalin wang <yalin.wang2010@gmail.com>
Date:   Thu Jan 14 15:18:48 2016 -0800

    mm: change mm_vmscan_lru_shrink_inactive() proto types

Update the lttng-modules instrumentation to match those changes.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: check reference counts for overflow

Linux kernel CVE-2016-0728 is a use-after-free based on overflow of the
reference counting mechanism.

Implement a kref wrapper in lttng that validates overflows, and use it
instead of kref_get(). Also check explicitly for overflows on file
fcount counters.

This should not be an issue in practice in lttng-modules because the ABI
is only exposed to root, but let's err on the safe side.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: RHEL 7.2 scsi instrumentation

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Fix: RHEL 7.2 kvm instrumentation

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Kconfig: describe both module and in-kernel compilation options

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add comments and indentation to Makefile

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>

Add support for built-in kernel build

To build the LTTng modules as builtins in a kernel image, simply run
the "built-in.sh" script with the path to you kernel source directory
as an argument. Then configure your kernel build and add the "CONFIG_LTTNG"
option. Build as usual and voila!

This is an early implementation with a single configuration option that
enables or disables everything, We could add fine grained config options
for each modules or group of modules.

Signed-off-by: Michael Jeanson <mjeanson@efficios.com>
Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>