9 months agosessiond: Extract condition hashing functions
Francis Deslauriers [Wed, 9 Sep 2020 21:36:12 +0000 (17:36 -0400)] 
sessiond: Extract condition hashing functions

Extract these functions so it can be used by other files.

The lttng_condition hashing code is kept in this (rather than
common/condition/condition.c) since it makes use of GPLv2 code
(hashtable utils), which we don't want to link in liblttng-ctl.

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Iaafe1402b2d198a00920d939502004038e78fff0

9 months agoCleanup: misplaced white space in `ERR()` statement
Francis Deslauriers [Wed, 9 Dec 2020 13:43:58 +0000 (08:43 -0500)] 
Cleanup: misplaced white space in `ERR()` statement

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I44291907c9973394c3edaf9b470230c59bb75eec

9 months agoAdd base support for event rule hit
Jonathan Rajotte [Mon, 17 Aug 2020 22:23:27 +0000 (18:23 -0400)] 
Add base support for event rule hit

Add some of the scafolding to support event-rule hit conditions.
This includes the hashing of event rule conditions and, consequently,
of event rules and the various probe location types.

The kernel module ABI is checked to verity that the kernel tracer
supports event notifiers.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Iab4db4fc7e9f0c5a7206106fa6a4781b6b95d306

9 months agosessiond: return 'invalid protocol' error on reception error
Jérémie Galarneau [Thu, 26 Nov 2020 20:36:03 +0000 (15:36 -0500)] 
sessiond: return 'invalid protocol' error on reception error

Signed-off-by: Jérémie Galarneau <>
Change-Id: I15758543ae51dd2ce30b40d88a05ef0492ce0e51

9 months agoOnly perform notification related unregistering when action is notify
Jonathan Rajotte [Mon, 17 Aug 2020 22:19:47 +0000 (18:19 -0400)] 
Only perform notification related unregistering when action is notify

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Id89eaf1c8f550e20adbd0b0d82462f6bf0b8ba21

9 months agoUse lttng_trigger_is_equal when iterating over the trigger ht
Jonathan Rajotte [Mon, 13 Jan 2020 18:40:12 +0000 (13:40 -0500)] 
Use lttng_trigger_is_equal when iterating over the trigger ht

Since a trigger can now have other type of actions then the notify one,
we must account for it. We use lttng_trigger_equal to perform that task.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I3300b0fff66e760152c1f7065d8fbfb945cce48e

9 months agoGenerate bytecodes related to the trigger on reception
Jonathan Rajotte [Mon, 23 Mar 2020 21:26:47 +0000 (17:26 -0400)] 
Generate bytecodes related to the trigger on reception

The compositing objects of a trigger might need to generate internal
bytecode. Doing it at the registration step allows an early validation
of the filter expressions.

There is no need to generate it for the unregister command since
bytecodes are not used for comparison and are for internal use only.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ia1282d55f028e6b056e8ff3877790894c582acdb

9 months agokernel: Add token field to `struct lttng_kernel_event`
Francis Deslauriers [Fri, 13 Nov 2020 21:27:59 +0000 (16:27 -0500)] 
kernel: Add token field to `struct lttng_kernel_event`

This field will be used by event notifier and counters features.

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I48d71a240150355d80b5a325717ca695467c5451

9 months agokernel: Add `struct lttng_kernel_syscall` to ABI
Francis Deslauriers [Wed, 25 Nov 2020 17:06:38 +0000 (12:06 -0500)] 
kernel: Add `struct lttng_kernel_syscall` to ABI

This struct is now used by the kernel tracer to allow to selectively
turn on and off syscalls event firing.

This way, the sessiond can decide to turn on only syscall entries,
exits, or both.

This will be used by the upcoming event notifier features to only
generate a notification on syscall entry.

This new struct doesn't change the layout of the `lttng_kernel_event`

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I478de30b91b415f517e9d0ac0686f3130f79d86b

9 months agoExtras: Perl 5.26 requires { to be escaped by \
Anders Wallin via lttng-dev [Wed, 25 Nov 2020 08:31:40 +0000 (09:31 +0100)] 
Extras: Perl 5.26 requires { to be escaped by \

Unescaped literal "{" characters in regular expression patterns are no
longer permissible

Signed-off-by: Anders Wallin <>
Signed-off-by: Jérémie Galarneau <>
9 months agoFix: sessiond: metadata not created on app unregistration during start
Jérémie Galarneau [Tue, 1 Dec 2020 21:51:23 +0000 (16:51 -0500)] 
Fix: sessiond: metadata not created on app unregistration during start

Issue observed

A test for an incoming feature (trigger actions on on-event conditions)
hangs. While this problem was discovered using this test, it exercises a
scenario that is problematic as of this fix.

The destruction of a session can hang if a single application being
traced unregisters (dies) during the 'start' of a session.


When a per-uid session is started, its buffers (channels and streams)
are allocated only if an instrumented application is registered to the
session daemon at that moment.

For historical reasons, the 'data' and 'metadata' buffers are allocated
in separate code paths. The 'data' buffers are allocated in
ust_app_synchronize() and the 'metadata' buffers are allocated in
ust_app_start_trace(). Both functions perform their own look-up for an
application session and will gracefully fail if an application session
can't be found; it typically means the application has exited.

This leaves a race window open where ust_app_synchronize() can succeed
in looking-up the application session, and ust_app_start_trace() can
fail following the death of the application.

When this occurs, the session is left with 'data' buffers allocated and
unallocated ''metadata' buffers. This is an unexpected state and results
in the rotation code attempting to rotate a partially initialized
metadata stream.

The rotation of this partially initialized metadata stream never
completes which, in turn, never allows the session to complete its
implicit rotation on destruction.

This race window is fairly narrow, but can be reproduced by sleep()-ing
at the beginning of ust_app_start_trace() and killing an application
that is being traced during the sleep period.


The creation of the metadata channel is performed as part of
ust_app_synchronize() if the application look-up succeeds. When it
fails, both 'data' and 'metadata' streams will fail to be created
resulting in an expected and valid state.

Known drawbacks


Signed-off-by: Jérémie Galarneau <>
Change-Id: Ice0ec16734a39a6bb885986d3ad70d20cd2618e0

9 months agotest: utils: lttng_pgrep performs lookup on non-existing pid
Jonathan Rajotte [Mon, 30 Nov 2020 18:54:14 +0000 (13:54 -0500)] 
test: utils: lttng_pgrep performs lookup on non-existing pid

Observed issue

 # Killing (signal SIGTERM) lttng-sessiond and lt-lttng-sessiond pids: 20962 20963
 ./tests/regression/tools/trigger/start-stop//../../../../utils/ line 103: /proc/20963/cmdline: No such file or directory


lttng_pgrep performs a two step search/validation for the pattern. Since
lttng_pgrep is used during tear-down of process (staged termination
signalling) a process returned by pgrep might exit before the second


Simply silence the error. The code flow already acknowledges the
possibility of failure here.

Known drawbacks



Fixes: #1292

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I82cb9fd4754c10a5104af495a8a959f4fbd92664

9 months agoFix: missing `_mutex_lock()` before signaling a condition variable
Francis Deslauriers [Mon, 30 Nov 2020 19:54:18 +0000 (14:54 -0500)] 
Fix: missing `_mutex_lock()` before signaling a condition variable

According to the PTHREAD_COND(3) man page, a condition variable
signaling and broadcast should alway be protected with a mutex.

This commit fixes two calls to `pthread_cond_signal()` function without
holding the right lock.

This commit also adds an assertion right before two calls to
`pthread_cond_broadcast()` where it's less obvious from the surrounding
code that the mutex is held. This documents the code and may be useful
for future debugging.

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Iebf5a8b2e4251bd1ff4cd462e548cd3486c6cb75

9 months agoCleanup: use `modprobe --remove` rather than `rmmod`
Francis Deslauriers [Tue, 15 Sep 2020 16:10:18 +0000 (12:10 -0400)] 
Cleanup: use `modprobe --remove` rather than `rmmod`

According to the rmmod(8) man page:
  rmmod is a trivial program to remove a module (when module unloading
  support is provided) from the kernel. Most users will want to use
  modprobe(8) with the -r option instead.

`rmmod` simply unloads the provided module and decrements the refcount
of the modules it depended on but doesn't unload those dependencies if
their refcount is zero.

With the following scenario we can end up if modules with a zero
refcount still loaded in the kernel:
  modprobe lttng-test
  ... (test case) ...
  ctrl+c sessiond
  rmmod lttng-test

When we teardown the lttng-sessiond, some modules are kept in the kernel
because the `lttng-test` module depends on them. So unloading
`lttng-test` using `rmmod` keeps those dependencies in the kernel.

Use `modprobe --remove` to unload modules and their now unused

From the modprobe(8) man page:
  -r, --remove
     This option causes modprobe to remove rather than insert a module.
     If the modules it depends on are also unused, modprobe will try to
     remove them too. Unlike insertion, more than one module can be
     specified on the command line

This commit also replaces existing uses of `modprobe -r` to `modprobe
--remove` for consistency.

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I7be83a645097e1eddd478cfbb717906b971f04ea

9 months agotrigger: consider domain on register and unregister
Jonathan Rajotte [Mon, 10 Feb 2020 01:33:55 +0000 (20:33 -0500)] 
trigger: consider domain on register and unregister

This allows the sessiond to inform the client if a trigger that requires a
particular domain (event rule based condition, for example) is at all

This is useful to fail early when a trigger being registered requires an
unavailable tracer.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I660937e64b294f6239ba15faeef705438a93a41a

9 months agotrigger: lttng_trigger_get_underlying_domain_type_restriction
Jonathan Rajotte [Wed, 25 Mar 2020 14:41:17 +0000 (10:41 -0400)] 
trigger: lttng_trigger_get_underlying_domain_type_restriction

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I5fe156a09e4e4c833f84a0fe9027c838b73fe728

9 months agoaction-executor: missing include of internal event-rule header
Jonathan Rajotte [Thu, 24 Sep 2020 19:36:43 +0000 (15:36 -0400)] 
action-executor: missing include of internal event-rule header

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: If541bb203f1d851750ee485fe9bd1a12d9963774

9 months agoTests: unit: lttng_condition_event_rule
Jonathan Rajotte [Wed, 4 Dec 2019 19:30:38 +0000 (14:30 -0500)] 
Tests: unit: lttng_condition_event_rule

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I281df3b2267d6ddf3b0591d181b7f276802d8963

9 months agocondition: implement event rule based condition
Jonathan Rajotte [Tue, 3 Dec 2019 20:57:08 +0000 (15:57 -0500)] 
condition: implement event rule based condition

An event rule condition is met when a tracer hit an event matching the
associated event rule.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I550903c231d83cb3852e8ef8aee2abafe9069b10

10 months agoMove conditions source files to src/common/conditions directory
Jonathan Rajotte [Tue, 3 Dec 2019 21:07:34 +0000 (16:07 -0500)] 
Move conditions source files to src/common/conditions directory

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I43165eacf82a1bf537e7187313664e32ca2833a9

10 months agotrigger: implement listing of registered trigger
Jonathan Rajotte [Thu, 23 Jan 2020 19:13:11 +0000 (14:13 -0500)] 
trigger: implement listing of registered trigger

Each client have visibility over triggers matching its user id (uid).

The root user have visibility over all registered triggers.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I3e5ae75939214ed85c376bea12f1e4b307d78976

10 months agoApply policy on channel sampling
Jonathan Rajotte [Tue, 4 Feb 2020 20:14:34 +0000 (15:14 -0500)] 
Apply policy on channel sampling

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Id755b73c1f976a5a7d7a188656a1de21bd703143

10 months agotrigger: introduce firing policies
Jonathan Rajotte [Thu, 23 Jan 2020 19:14:14 +0000 (14:14 -0500)] 
trigger: introduce firing policies

A firing policy controls the rate of firing of a trigger.

Two firing policy mode are implemented:
       The triggers's actions are executed every N times the
       condition occurs.
       The triggers's actions are executed once the condition was met N

Firing policies will be moved to the specific `action` objects
in a follow-up commit as not all actions can implement the firing

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ifaeeaaec7b6f2bed57d0d5f4ed8546762ec02e8d

10 months agoFix: lttng-ctl: deserialize on orderly shutdown of sessiond
Francis Deslauriers [Mon, 16 Nov 2020 21:50:41 +0000 (16:50 -0500)] 
Fix: lttng-ctl: deserialize on orderly shutdown of sessiond

The `recv_data_sessiond()` function may return zero if the socket peer
has shutdown orderly. This happens if the session daemon is killed while
the client is blocked on the `recv_data_sessiond()` call. Currently,
when this happens, the client simply goes on to decode the uninitialized
reply buffer.

This bug was witnessed while developing the upcoming event-notifier
feature where complex objects are received from sessiond and attempts to
deserialize these objects resulted in segmentation faults.

Return -LTTNG_ERR_NO_SESSIOND when `recvmsg()` returns zero. This way,
the client can simply tell the user that the session daemon is no longer

Signed-off-by: Francis Deslauriers <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ib2387526c4101e3bae706e38181bfeb25da26fa3

10 months agoFix: trigger: erroneous check for success of trigger creation
Jérémie Galarneau [Wed, 18 Nov 2020 22:12:45 +0000 (17:12 -0500)] 
Fix: trigger: erroneous check for success of trigger creation

6808ef55e added a check for `ret == 0` to determine if a trigger
could be created from a payload. The function returns >= 0 on
success, leading to crashes when a trigger is de-serialized.

Signed-off-by: Jérémie Galarneau <>
Change-Id: Icd769dcb04f7637aa1877436e9a5570e7f20b63b

10 months agoFix: trigger: leak of trigger on failure to set name
Jérémie Galarneau [Wed, 18 Nov 2020 19:14:02 +0000 (14:14 -0500)] 
Fix: trigger: leak of trigger on failure to set name

lttng_trigger_create_from_payload() leaks its newly-created
trigger when it fails to set the trigger's name. Drop
the reference to the new trigger whenever the function fails.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I9dbf91d404fd67e4b79f2af550f3768680d6d4ec

10 months agoClean-up: trigger: use condition and action put
Jérémie Galarneau [Wed, 18 Nov 2020 19:04:03 +0000 (14:04 -0500)] 
Clean-up: trigger: use condition and action put

Use the internal *_put() functions to discard condition and
action references rather than the public *_destroy() functions
as they may cause confusion.

Signed-off-by: Jérémie Galarneau <>
Change-Id: Idfdfda3ea2289315408245074f7cc0de6541167a

10 months agoDocs: payload/buffer view: validate is missing an argument description
Jérémie Galarneau [Wed, 18 Nov 2020 16:55:24 +0000 (11:55 -0500)] 
Docs: payload/buffer view: validate is missing an argument description

Signed-off-by: Jérémie Galarneau <>
Change-Id: I3d575dcda6c3e6820e911ab3c4e28b18d29f045c

10 months agoFix: unchecked buffer size for communication header
Jérémie Galarneau [Sat, 14 Nov 2020 02:39:36 +0000 (21:39 -0500)] 
Fix: unchecked buffer size for communication header

A number of object de-serialization functions rely on a
fixed-size communication header to create an object from
a payload.

A large number of those functions assume that the initial
header fits in the provided buffer or payload view. Also,
the functions that do validate that the header fits do so
in different ways:
  - checking the view's size,
  - creating a new fixed-size view and checking the 'data' pointer.

To harmonize all of those checks, the following utils are added:
  - lttng_buffer_view_is_valid()
  - lttng_payload_view_is_valid()

These functions should be used whenever a fixed-size view is
created (not passing -1 as the length parameter).

The checks are added and/or harmonized to:
  - create a new 'header' view,
  - validate it with the corresponding *_is_valid() function,
  - initialize the header pointer using the header view.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I763946feac714ecef4fc5bd427dab2d3fe5dc1a4

10 months agorelayd: logging of `trace chunk exists` command refers to the wrong command
Jérémie Galarneau [Mon, 16 Nov 2020 21:10:09 +0000 (16:10 -0500)] 
relayd: logging of `trace chunk exists` command refers to the wrong command

Signed-off-by: Jérémie Galarneau <>
Change-Id: I6e2bf4eee379f4e1d42333779dfeaf8f087d8217

10 months agotrigger: lttng_triggers: implement a container for multiple triggers
Jonathan Rajotte [Tue, 21 Jan 2020 19:22:37 +0000 (14:22 -0500)] 
trigger: lttng_triggers: implement a container for multiple triggers

This container is exposed for the listing of triggers.

We also plan on using it internally in the sessiond for inter-thread

The current implementation is backed by a lttng_dynamic_pointer_array.

Caller of lttng_triggers_add is responsible for managing ownership via
ref-counting of the lttng_trigger object.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ib541027a6d7d856daa746de5aa49f0002bbe036f

10 months agoaction-executor: evaluated object credentials are optional
Jonathan Rajotte [Wed, 23 Sep 2020 20:13:37 +0000 (16:13 -0400)] 
action-executor: evaluated object credentials are optional

Use the is_set member instead of the LTTNG_OPTIONAL_GET_PTR macro
which asserts whenever an optional member is unset.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ia00e4a7f5f9b8198061a742bf6bd750c721908cf

10 months agotrigger: generate and add tracer token on registration
Jonathan Rajotte [Wed, 9 Sep 2020 21:16:53 +0000 (17:16 -0400)] 
trigger: generate and add tracer token on registration

Assign a unique tracer token to a trigger.

This token will be used as the unique id that will be communicated back
to the sessiond by the tracers for tracer notification.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I2033dcaa4c5536b29dd4d7c57933e1aa686082cd

10 months agoaction-executor: add trigger name to debugging output
Jonathan Rajotte [Thu, 24 Sep 2020 19:14:47 +0000 (15:14 -0400)] 
action-executor: add trigger name to debugging output

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I73f8fda4b7fee331700988ea73471e3cb1516ed6

10 months agotrigger: implement trigger naming
Jonathan Rajotte [Mon, 23 Mar 2020 22:27:59 +0000 (18:27 -0400)] 
trigger: implement trigger naming

A trigger can now have an optional name on the client side.

If no name is provided the sessiond will generate a name and return a
trigger object to populate the client side object.

For now, the name generation code generate the following pattern: TN

Where `N` is incremented each time a name has to be generated. If a
collision occurs, we increment `N` as needed.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I5f303610713c049177e53937bfc9824cd61501e4

10 months agoport: run namespace tests only on Linux
Michael Jeanson [Tue, 13 Oct 2020 23:19:10 +0000 (19:19 -0400)] 
port: run namespace tests only on Linux

Change-Id: I574d6e7419715e191fb9102e4cfc916ea0e529aa
Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
10 months agoport: FreeBSD does support fchown and fchmod on a shm fd
Michael Jeanson [Wed, 4 Nov 2020 15:04:12 +0000 (10:04 -0500)] 
port: FreeBSD does support fchown and fchmod on a shm fd

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Iadff886d593ae3f77a4e96dfbfe02d1c1ea45f1e

10 months agoport: Add pthread_setname_np FreeBSD compat
Michael Jeanson [Thu, 29 Oct 2020 10:09:41 +0000 (06:09 -0400)] 
port: Add pthread_setname_np FreeBSD compat

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I7ca8334c4ce28bc240c898aeb5a6857ff951143b

10 months agoport: only enable userspace callstack context on Linux
Michael Jeanson [Wed, 14 Oct 2020 14:32:14 +0000 (10:32 -0400)] 
port: only enable userspace callstack context on Linux

Change-Id: I55402a7058f7d0bbe11d4c59197197130fe88665
Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
10 months agotrigger: implement is_equal
Jonathan Rajotte [Tue, 24 Mar 2020 15:32:08 +0000 (11:32 -0400)] 
trigger: implement is_equal

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I646c13e7fb26fda66b888ce90253e87567b2cab8

10 months agotrigger: expose trigger owner uid
Jonathan Rajotte [Fri, 18 Sep 2020 20:37:50 +0000 (16:37 -0400)] 
trigger: expose trigger owner uid

To facilitate behavior management for the root user and to allow
duplicate trigger names across users, enforce the usage of the trigger
owner user id.

The root user will be able to register and unregister triggers on behalf
of other users. The root user will also have visibility on triggers of
other users.

Only the root user can use the `lttng_trigger_set_owner_uid` function
successfully. As indicated in the comments, this function performs
a client-side validation steps to catch mis-uses, but this is
properly enforced on the sessiond's end in the register/unregister
trigger commands.

With the future addition of a trigger name (id), the owner id and the
name will act as a key tuple allowing identicaly named triggers across

We plan on exposing the `--user` switch in the upcoming command line
(add-trigger, remove-trigger).

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ifca3c41b7ffd97b67e16fb80c18472b667cb2f56

10 months agoClean-up: action-executor: typo and missing tab
Jonathan Rajotte [Fri, 22 May 2020 15:27:37 +0000 (11:27 -0400)] 
Clean-up: action-executor: typo and missing tab

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I5646fae2db98a3c8ffa0ba92aff9815f4ce0cf53

10 months agoTests: Fix: 99% fill ratio for high buffer usage is too high for larger events
Jonathan Rajotte [Thu, 28 May 2020 01:29:05 +0000 (21:29 -0400)] 
Tests: Fix: 99% fill ratio for high buffer usage is too high for larger events

If the event being registered is bigger than 1% of a subbuffer, the 99%
ratio cannot be achieved since the "last event" necessary to go over 99%
will always be dropped by the tracer.

  DBG1 - 19:31:07.665963875 [Notification]: [notification-thread] High buffer usage condition being evaluated: threshold = 16220, highest usage = 16196 (in evaluate_buffer_usage_condition() at notification-thread-events.c:3733)

We use a ratio of 90% to keep a little headroom.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I06180735e0b5e88209b888e51cc83b4ac7d98193

10 months agoFix: action: invalid header offset used when serializing snapshot action
Jonathan Rajotte [Wed, 8 Jul 2020 02:51:27 +0000 (22:51 -0400)] 
Fix: action: invalid header offset used when serializing snapshot action

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I77f5fab214f6721773147968ea3b85dddfea8d62

10 months agoport: FreeBSD has no ENODATA, alias it to ENOATTR
Michael Jeanson [Tue, 13 Oct 2020 21:33:44 +0000 (17:33 -0400)] 
port: FreeBSD has no ENODATA, alias it to ENOATTR

According to 'the internet' ENOATTR is used in a similar fashion to
ENODATA on the BSDs and we used it internally only anyway.

Change-Id: Ia4e77fd6d28c9dfb43f99ddba6c32369384827f0
Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
10 months agoport: tests: /proc/self/fd is Linux only, use /dev/fd on other Unices
Michael Jeanson [Tue, 20 Oct 2020 19:02:45 +0000 (15:02 -0400)] 
port: tests: /proc/self/fd is Linux only, use /dev/fd on other Unices

Change-Id: I2be8120c7dce3f12daaf12a190810a145afa50b6
Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
10 months agoCleanup: Use pkg-config to detect liburcu
Michael Jeanson [Fri, 30 Oct 2020 06:48:08 +0000 (02:48 -0400)] 
Cleanup: Use pkg-config to detect liburcu

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I88d3f853c8ee0e14a38a462ce24626800e0a4caf

10 months agoClean-up: sessiond: silence negative index warning
Jérémie Galarneau [Thu, 29 Oct 2020 15:43:35 +0000 (11:43 -0400)] 
Clean-up: sessiond: silence negative index warning

Coverity warns that `lttng_action_get_type()` can return
a negative index (LTTNG_ACTION_TYPE_UNKNOWN). This scenario
is not reachable, but a check is added to silence the analyzer.

Original report:
  1435955 Negative array index read

  A memory location at a negative offset from the beginning of the array
  will be read, resulting in incorrect values.

  In get_action_name: Negative value used to index an array in a read
  operation (CWE-129)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <>
Change-Id: I5952096a1d29f0d4a3c4350a2a842874d5f3973b

10 months agocredentials: uid and gid now use LTTNG_OPTIONAL
Jonathan Rajotte [Fri, 25 Sep 2020 20:35:28 +0000 (16:35 -0400)] 
credentials: uid and gid now use LTTNG_OPTIONAL

The triggers will only use the uid element.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ia96e7def5ab560d9af1476920426635fc49f92ef

10 months agoport: Add missing sock_cred macros on FreeBSD
Michael Jeanson [Tue, 13 Oct 2020 23:06:09 +0000 (19:06 -0400)] 
port: Add missing sock_cred macros on FreeBSD

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I71f51ef61bf659c758edba6fd27faeef56654acf

10 months agoport: use compat lttng_fls()
Michael Jeanson [Tue, 13 Oct 2020 22:55:23 +0000 (18:55 -0400)] 
port: use compat lttng_fls()

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I698b31a24c5b442a00fe570a0ac53e23bb817bec

10 months agoport: FreeBSD has no LOGIN_NAME_MAX, use sysconf instead
Michael Jeanson [Tue, 13 Oct 2020 22:44:40 +0000 (18:44 -0400)] 
port: FreeBSD has no LOGIN_NAME_MAX, use sysconf instead

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Id058e15608ce0332500343ce389365a6fb1a40cc

10 months agoport: no eventfd support on FreeBSD
Michael Jeanson [Tue, 13 Oct 2020 22:44:19 +0000 (18:44 -0400)] 
port: no eventfd support on FreeBSD

It's only used in the tests to create dummy fds, use fcntl to duplicate
the stdout fd instead.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I401f2bfe6a2375a9bf4d895956071f74e5684783

10 months agooptional: Add LTTNG_OPTIONAL_INIT_VALUE
Jérémie Galarneau [Fri, 2 Oct 2020 21:25:11 +0000 (17:25 -0400)] 

Add helper to initialize an optional field to a 'set' value.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I439302ebec2433abcf7edb6167bf5b02db5a9a55

10 months agoaction: Mark parameter of lttng_action_get_type as const
Jonathan Rajotte [Wed, 23 Sep 2020 18:34:59 +0000 (14:34 -0400)] 
action: Mark parameter of lttng_action_get_type as const

Remove lttng_action_get_type_const as it is no longer needed.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I1525bc2c89eb37ab3e75d915c6ff50bd2a7f5d21

10 months agoIntroduce lttng_domain_type_str utility
Jonathan Rajotte [Tue, 29 Sep 2020 15:46:24 +0000 (11:46 -0400)] 
Introduce lttng_domain_type_str utility

Change-Id: I1d2c7be968da6658e93407cdba26a6042177badd
Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
10 months agoport: no HOST_NAME_MAX on FreeBSD, use LTTNG_HOST_NAME_MAX
Michael Jeanson [Tue, 13 Oct 2020 21:54:27 +0000 (17:54 -0400)] 

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I83cc40a123539a668c25828144905b628df9fdef

10 months agoport: ELF_ST_TYPE is defined in elf.h on FreeBSD
Michael Jeanson [Tue, 13 Oct 2020 21:54:04 +0000 (17:54 -0400)] 
port: ELF_ST_TYPE is defined in elf.h on FreeBSD

No need to alias ELF32_ST_TYPE to ELF_ST_TYPE.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I8afa2fb9d96b81d994b90c8291f2f457a037a525

10 months agoport: posix_fadvise is available in FreeBSD >= 10.0
Michael Jeanson [Tue, 13 Oct 2020 21:32:14 +0000 (17:32 -0400)] 
port: posix_fadvise is available in FreeBSD >= 10.0

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I85f823ad7be94a5860ce0104c20e5a49ce030eda

10 months agoport: fix compat/endian.h on FreeBSD
Michael Jeanson [Tue, 13 Oct 2020 21:32:00 +0000 (17:32 -0400)] 
port: fix compat/endian.h on FreeBSD

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: If591ed8d1cf50c1914a613976e9e285c3647906c

10 months agoport: ls --ignore= is a GNU extension
Michael Jeanson [Wed, 14 Oct 2020 18:32:37 +0000 (14:32 -0400)] 
port: ls --ignore= is a GNU extension

Use grep -v instead to filter README.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I8fb6aba97ba1484aff511d59eeb4584e9672659e

10 months agoTests: poll: test all possible combinations of active fds in a poll set
Jérémie Galarneau [Tue, 27 Oct 2020 21:23:45 +0000 (17:23 -0400)] 
Tests: poll: test all possible combinations of active fds in a poll set

The poll compatibility layer used on all non-Linux platforms would
hang for certain combinations of active file descriptors reported
by poll.

A new test is introduced to try all combinations of active file
descriptors for a given number of file descriptors in a poll set.

The unit test tries all combinations of 8 file descriptors which
exercises all the current compatibility code and ensures the
test concludes rapidly.

Signed-off-by: Jérémie Galarneau <>
Change-Id: Ie479c4f2d85917713d3f2bdc1e4f0423ca9243af

10 months agoFix: common: poll: compat_poll_wait never finishes
Jérémie Galarneau [Fri, 16 Oct 2020 18:43:39 +0000 (14:43 -0400)] 
Fix: common: poll: compat_poll_wait never finishes

compat_poll_wait hangs when poll returns an array of file
descriptors of the form:
  [ Inactive Active ]

The logic to find the first idle pollfd entry is bogus and actually
skips the first idle entry. This causes the follow-up loop to never

The pollfd array defragmentation logic is re-written in a simpler
style to handle those cases appropriately.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I8669a870df1ec1160f05e35e83671917bb80d6f9

10 months agoTests: Add syscall enable/disable scenarios
Michael Jeanson [Thu, 3 Sep 2020 15:04:46 +0000 (11:04 -0400)] 
Tests: Add syscall enable/disable scenarios

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ic3d9e739b01a0cf2bffb7c103911b3b51520010e

10 months agoCleanup: simplify 'poll' wrapper build
Michael Jeanson [Wed, 26 Aug 2020 15:39:15 +0000 (11:39 -0400)] 
Cleanup: simplify 'poll' wrapper build

Remove the AM conditionnal and merge the sources in single files like the
other wrappers. This removes a special case from the build system.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I6078f6013e52c3bc7c74cb8937f3741453c65874

10 months agoCleanup: autoconf 'dirfd' detection
Michael Jeanson [Wed, 26 Aug 2020 15:17:10 +0000 (11:17 -0400)] 
Cleanup: autoconf 'dirfd' detection

Remove the unused AM conditionnal and use the 'HAVE_' prefix for the
define like the other detected features.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I9a001051a14e2360e7f66fd4f627f97b11563c4f

10 months agoSet version to 2.13-pre
Michael Jeanson [Tue, 6 Oct 2020 14:24:56 +0000 (10:24 -0400)] 
Set version to 2.13-pre

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ib63daa19b91c4cd94caf4fd6cbdfd6fd1e8f015b

11 months agorelayd: silence null dereference warning during viewer stream creation
Jérémie Galarneau [Fri, 16 Oct 2020 12:25:10 +0000 (08:25 -0400)] 
relayd: silence null dereference warning during viewer stream creation

Coverity warns that the vstream's trace chunk may be used NULL.
However, this won't happen if the corresponding relay stream has
an active trace chunk.

Coverity report:
  1433620 Dereference after null check

  Either the check against null is unnecessary, or there may be a
  null pointer dereference.

  In viewer_stream_create: Pointer is checked against null but then
  dereferenced anyway (CWE-476)

Reported-by: Coverity Scan
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ie032ed415a99cfff149e3325d05f37ededb52d33

11 months agoFix: relayd: failure to read index entry or stream packet after clear
Jérémie Galarneau [Wed, 7 Oct 2020 18:10:35 +0000 (14:10 -0400)] 
Fix: relayd: failure to read index entry or stream packet after clear

Observed issue

The clear tests occasionally fail with the following babeltrace error
when a live session is stopped following a "clear". Unfortunately, this
problem only seems to occur on certain machines. In my case, I only
managed to reproduce this on the CI's workers.

  10-07 12:39:48.333  7679  7679 E PLUGIN/SRC.CTF.LTTNG-LIVE/VIEWER lttng_live_get_stream_bytes@viewer-connection.c:1610 [lttng-live] Received get_data_packet response: error
  10-07 12:39:48.333  7679  7679 E PLUGIN/CTF/MSG-ITER request_medium_bytes@msg-iter.c:563 [lttng-live] User function failed: status=ERROR
  10-07 12:39:48.333  7679  7679 E PLUGIN/CTF/MSG-ITER ctf_msg_iter_get_next_message@msg-iter.c:2899 [lttng-live] Cannot handle state: msg-it-addr=0x5603c28e2830, state=DSCOPE_TRACE_PACKET_HEADER_BEGIN
  10-07 12:39:48.333  7679  7679 E PLUGIN/SRC.CTF.LTTNG-LIVE lttng_live_iterator_next_handle_one_active_data_stream@lttng-live.c:845 [lttng-live] CTF message iterator failed to get next message: msg-iter=0x5603c28e2830, msg-iter-status=ERROR
  10-07 12:39:48.333  7679  7679 E PLUGIN/SRC.CTF.LTTNG-LIVE lttng_live_msg_iter_next@lttng-live.c:1665 [lttng-live] Error preparing the next batch of messages: live-iter-status=LTTNG_LIVE_ITERATOR_STATUS_ERROR
  10-07 12:39:48.333  7679  7679 W LIB/MSG-ITER bt_message_iterator_next@iterator.c:864 Component input port message iterator's "next" method failed: iter-addr=0x5603c28cb0f0, iter-upstream-comp-name="lttng-live", iter-upstream-comp-log-level=WARNING, iter-upstream-comp-class-type=SOURCE, iter-upstream-comp-class-name="lttng-live", iter-upstream-comp-class-partial-descr="Connect to an LTTng relay daemon", iter-upstream-port-type=OUTPUT, iter-upstream-port-name="out", status=ERROR
  10-07 12:39:48.333  7679  7679 E PLUGIN/FLT.UTILS.MUXER muxer_upstream_msg_iter_next@muxer.c:454 [muxer] Upstream iterator's next method returned an error: status=ERROR
  10-07 12:39:48.333  7679  7679 E PLUGIN/FLT.UTILS.MUXER validate_muxer_upstream_msg_iters@muxer.c:991 [muxer] Cannot validate muxer's upstream message iterator wrapper: muxer-msg-iter-addr=0x5603c28dbe70, muxer-upstream-msg-iter-wrap-addr=0x5603c28cd0f0
  10-07 12:39:48.333  7679  7679 E PLUGIN/FLT.UTILS.MUXER muxer_msg_iter_next@muxer.c:1415 [muxer] Cannot get next message: comp-addr=0x5603c28dc960, muxer-comp-addr=0x5603c28db0a0, muxer-msg-iter-addr=0x5603c28dbe70, msg-iter-addr=0x5603c28caf80, status=ERROR
  10-07 12:39:48.333  7679  7679 W LIB/MSG-ITER bt_message_iterator_next@iterator.c:864 Component input port message iterator's "next" method failed: iter-addr=0x5603c28caf80, iter-upstream-comp-name="muxer", iter-upstream-comp-log-level=WARNING, iter-upstream-comp-class-type=FILTER, iter-upstream-comp-class-name="muxer", iter-upstream-comp-class-partial-descr="Sort messages from multiple inpu", iter-upstream-port-type=OUTPUT, iter-upstream-port-name="out", status=ERROR
  10-07 12:39:48.333  7679  7679 W LIB/GRAPH consume_graph_sink@graph.c:473 Component's "consume" method failed: status=ERROR, comp-addr=0x5603c28dcb60, comp-name="pretty", comp-log-level=WARNING, comp-class-type=SINK, comp-class-name="pretty", comp-class-partial-descr="Pretty-print messages (`text` fo", comp-class-is-frozen=0, comp-class-so-handle-addr=0x5603c28c8140, comp-class-so-handle-path="/home/jenkins/jgalar-debug/build/usr/lib/babeltrace2/plugins/", comp-input-port-count=1, comp-output-port-count=0
  10-07 12:39:48.333  7679  7679 E CLI cmd_run@babeltrace2.c:2548 Graph failed to complete successfully
  10-07 12:39:48.333  7679  7679 E PLUGIN/SRC.CTF.LTTNG-LIVE/VIEWER lttng_live_session_detach@viewer-connection.c:1227 [lttng-live] Unknown detach return code 0

  ERROR:    [Babeltrace CLI] (babeltrace2.c:2548)
    Graph failed to complete successfully
  CAUSED BY [libbabeltrace2] (graph.c:473)
    Component's "consume" method failed: status=ERROR, comp-addr=0x5603c28dcb60,
    comp-name="pretty", comp-log-level=WARNING, comp-class-type=SINK,
    comp-class-name="pretty", comp-class-partial-descr="Pretty-print messages
    (`text` fo", comp-class-is-frozen=0, comp-class-so-handle-addr=0x5603c28c8140,
    comp-input-port-count=1, comp-output-port-count=0
  CAUSED BY [libbabeltrace2] (iterator.c:864)
    Component input port message iterator's "next" method failed:
    iter-addr=0x5603c28caf80, iter-upstream-comp-name="muxer",
    iter-upstream-comp-log-level=WARNING, iter-upstream-comp-class-type=FILTER,
    iter-upstream-comp-class-partial-descr="Sort messages from multiple inpu",
    iter-upstream-port-type=OUTPUT, iter-upstream-port-name="out", status=ERROR
  CAUSED BY [muxer: 'filter.utils.muxer'] (muxer.c:991)
    Cannot validate muxer's upstream message iterator wrapper:
  CAUSED BY [muxer: 'filter.utils.muxer'] (muxer.c:454)
    Upstream iterator's next method returned an error: status=ERROR
  CAUSED BY [libbabeltrace2] (iterator.c:864)
    Component input port message iterator's "next" method failed:
    iter-addr=0x5603c28cb0f0, iter-upstream-comp-name="lttng-live",
    iter-upstream-comp-log-level=WARNING, iter-upstream-comp-class-type=SOURCE,
    iter-upstream-comp-class-partial-descr="Connect to an LTTng relay daemon",
    iter-upstream-port-type=OUTPUT, iter-upstream-port-name="out", status=ERROR
  CAUSED BY [lttng-live: 'source.ctf.lttng-live'] (lttng-live.c:1665)
    Error preparing the next batch of messages:
  CAUSED BY [lttng-live: 'source.ctf.lttng-live'] (lttng-live.c:845)
    CTF message iterator failed to get next message: msg-iter=0x5603c28e2830,
  CAUSED BY [lttng-live: 'source.ctf.lttng-live'] (msg-iter.c:2899)
    Cannot handle state: msg-it-addr=0x5603c28e2830,
  CAUSED BY [lttng-live: 'source.ctf.lttng-live'] (msg-iter.c:563)
    User function failed: status=ERROR
  CAUSED BY [lttng-live: 'source.ctf.lttng-live'] (viewer-connection.c:1610)
    Received get_data_packet response: error

This occurs immediately following a 'stop' on the session. As the error
indicates, a request to obtain a data packet fails with a generic
error reply.

Moreover, the following LTTNG_VIEWER_DETACH_SESSION appears to fail
with an invalid status code. This is addressed in a different commit.

Reproducing the test's failure without redirecting the relay daemon's
allows us to see the following errors after the first stop:
  PERROR - 14:33:44.929675253 [25108/25115]: Failed to open fs handle to ust/uid/1001/64-bit/index/chan_0.idx, open() returned: No such file or directory (in fd_tracker_open_fs_handle() at fd-tracker.c:550)
  PERROR - 14:33:45.030037417 [25108/25115]: Failed to open fs handle to ust/uid/1001/64-bit/index/chan_0.idx, open() returned: No such file or directory (in fd_tracker_open_fs_handle() at fd-tracker.c:550)
  PERROR - 14:33:45.130429370 [25108/25115]: Failed to open fs handle to ust/uid/1001/64-bit/index/chan_0.idx, open() returned: No such file or directory (in fd_tracker_open_fs_handle() at fd-tracker.c:550)
  PERROR - 14:33:45.230829447 [25108/25115]: Failed to open fs handle to ust/uid/1001/64-bit/index/chan_0.idx, open() returned: No such file or directory (in fd_tracker_open_fs_handle() at fd-tracker.c:550)
  PERROR - 14:33:45.331223320 [25108/25115]: Failed to open fs handle to ust/uid/1001/64-bit/index/chan_0.idx, open() returned: No such file or directory (in fd_tracker_open_fs_handle() at fd-tracker.c:550)

This is produced with the following back-trace:
  (gdb) bt
  #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
  #1  0x00007ffff69648b1 in __GI_abort () at abort.c:79
  #2  0x00005555555b4f1f in fd_tracker_open_fs_handle (tracker=0x55555582c620, directory=0x7fffe8006680,
      path=0x7ffff0a25870 "ust/uid/1001/64-bit/index/chan_1.idx", flags=0, mode=0x7ffff0a24508) at fd-tracker.c:550
  #3  0x0000555555595c34 in _lttng_trace_chunk_open_fs_handle_locked (chunk=0x7fffe0002130, file_path=0x7ffff0a25870 "ust/uid/1001/64-bit/index/chan_1.idx",
      flags=0, mode=432, out_handle=0x7ffff0a24710, expect_no_file=true) at trace-chunk.c:1388
  #4  0x0000555555595eef in lttng_trace_chunk_open_fs_handle (chunk=0x7fffe0002130, file_path=0x7ffff0a25870 "ust/uid/1001/64-bit/index/chan_1.idx", flags=0,
      mode=432, out_handle=0x7ffff0a24710, expect_no_file=true) at trace-chunk.c:1433
  #5  0x00005555555da6c2 in _lttng_index_file_create_from_trace_chunk (chunk=0x7fffe0002130, channel_path=0x7fffe8018c30 "ust/uid/1001/64-bit",
      stream_name=0x7fffe8018c10 "chan_1", stream_file_size=0, stream_file_index=0, index_major=1, index_minor=1, unlink_existing_file=false, flags=0,
      expect_no_file=true, file=0x7fffe0002270) at index.c:97
  #6  0x00005555555dad8a in lttng_index_file_create_from_trace_chunk_read_only (chunk=0x7fffe0002130, channel_path=0x7fffe8018c30 "ust/uid/1001/64-bit",
      stream_name=0x7fffe8018c10 "chan_1", stream_file_size=0, stream_file_index=0, index_major=1, index_minor=1, expect_no_file=true, file=0x7fffe0002270)
      at index.c:186
  #7  0x000055555557640f in try_open_index (vstream=0x7fffe0002250, rstream=0x7fffe8018c50) at live.c:1378
  #8  0x0000555555577155 in viewer_get_next_index (conn=0x7fffd4001440) at live.c:1643
  #9  0x0000555555579a01 in process_control (recv_hdr=0x7ffff0a27c30, conn=0x7fffd4001440) at live.c:2311
  #10 0x000055555557a1db in thread_worker (data=0x0) at live.c:2482
  #11 0x00007ffff6d1c6db in start_thread (arg=0x7ffff0a28700) at pthread_create.c:463
  #12 0x00007ffff6a45a3f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

That problem is mostly cosmetic in nature (the open can fail
"legitimately") as the PERROR should simply not be printed and is
addressed in a different commit.

This error is also produced after a 'clear' is issued:
  PERROR - 14:33:45.532782268 [25108/25115]: Failed to read from file system handle of viewer stream id 1, offset: 4096: No such file or directory (in viewer_get_packet() at live.c:1849)

Which is produced with the following back-trace:
  #0  __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:51
  #1  0x00007f53e297c8b1 in __GI_abort () at abort.c:79
  #2  0x000055dd77ccef2c in viewer_get_packet (conn=0x7f53c4001100) at live.c:1850
  #3  0x000055dd77cd0a15 in process_control (recv_hdr=0x7f53dca3fc30, conn=0x7f53c4001100) at live.c:2315
  #4  0x000055dd77cd11db in thread_worker (data=0x0) at live.c:2483
  #5  0x00007f53e2d346db in start_thread (arg=0x7f53dca40700) at pthread_create.c:463
  #6  0x00007f53e2a5da3f in clone () at ../sysdeps/unix/sysv/linux/x86_64/clone.S:95

A similar problem occurs, although more rarely, when reading an
index entry in viewer_get_next_index().


The following situation leads to both failures to get a
packet and failures to get the next index:
  - Viewer connects to an existing session,
  - Viewer consumes a number of packets, alternating the
    GET_NEXT_INDEX and GET_PACKET command,
  - The session's streams are rotated to a new trace chunk
    (as part of a clear),
  - The session is started and stopped, causing new packets
    to be produced and received,
  - The session is stopped and destroyed, causing the session's
    streams to rotate into a "null" trace chunk (no active
    trace files),
  - Viewer issues GET_NEXT_INDEX or GET_PACKET, but the fact
    that a rotation occurred on the receiving end is not detected
    as the relay streams' trace chunk are "null".

The crux of the problem is that lttng_trace_chunk_ids_equal() is
bypassed when the current trace chunk of a relay stream is "null".

The rationale for skipping this check is that it is assumed that the
files currently opened by the live server can can still be used even
if the consumer has rotated the corresponding streams into a 'null'
trace chunk, meaning no trace chunk is 'set' for those streams.

This makes sense in one scenario: the session was destroyed and we wish
to allow a connected live client to finish consuming the trace packets
up to the end of the session's lifetime.

Here, the situation is different. The viewer is reading chunk 'A'.
Meanwhile, a rotation occurs into chunk 'B' and packets are received for
chunk 'B'. Then, a rotation to a 'null' chunk (no active chunk) occurs.

In essence, the live server never sees the rotation between chunk 'A'
and 'B', and simply assumes that a rotation from 'A' to 'null' occurred,
as would happen at the end of a session.

In terms of the code, in viewer_get_next_index(), a call to
check_index_status() is performed to determine if an index is available.
The function checks that `index_received_seqcount` is greater than
`index_sent_seqcount`. In that case, it determines that an index must be

Unfortunately, there is no way for the live server to determine that the
remaining indexes are in a chunk that doesn't exist anymore (chunk 'B').
Thus, viewer_get_next_index() attempts to read an index entry from the
current index file and fails.


1) lttng_trace_chunk_ids_equal() is modified to properly handle
'null' trace chunks:
  - A null and a non-null trace chunk are not equal,
  - Two null trace chunks are equal.

2) Rotation count
  A rotation counter is introduced to track the number of rotations
  that occurred during a relay stream's lifetime. This counter is
  sampled by the matching viewer streams on creation and on rotation
  and is used to determine if all rotations were "seen" by the viewer

  Hence, this allows us to handle the special case where a viewer
  is consuming the contents of a relay stream that just transitioned
  into a 'null' trace chunk (see comments in patch).

The rest of the modifications simply allow the live server to handle
null trace chunks in viewer streams. This fixes another unrelated bug
that I observed while investigating this: sessions that don't have an
active trace chunk are not shown when listing sessions with babeltrace.

To reproduce, simply stop, clear a session, and attempt to list the
sessions of the associated relay daemon.

Known drawbacks


Signed-off-by: Jérémie Galarneau <>
Change-Id: Ibb3116990e34b7ec3b477f3482d0c0ff1e848d09

11 months agoFix: lttng-ctl: erroneous uses of LTTNG_PACKED
Jérémie Galarneau [Tue, 13 Oct 2020 18:55:33 +0000 (14:55 -0400)] 
Fix: lttng-ctl: erroneous uses of LTTNG_PACKED

The LTTNG_PACKED macro uses gcc attributes to indicate that a structure
should be packed. Hence, this macro obeys the same rules as the gcc

Various mis-uses of the LTTNG_PACKED macros may result in structure not
being packed:
  - The LTTNG_PACKED macro should always be placed _before_ an identifier
    when a structure is declared in-place.
  - Adding LTTNG_PACKED at the definition site has no effect if the
    structure was declared elsewhere.

Those mis-uses cause issues when mixing the bitness (32/64) of the
session daemon and liblttng-ctl.

Outstanding issues include the following structures that are not
tagged as LTTNG_PACKED:
  - struct lttng_event
  - struct lttng_channel
  - struct lttng_event_context

Unfortunately, those structures are exposed by the public API and
can't be tagged as being "packed". Doing so would break the ABI
of liblttng-ctl.

These structures should be packed/unpacked explicitly.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I095dc0dffc6bf9e15dc7a7ec797958a5780ef150

11 months agoFix: relayd: live: invalid return code on DETACH_SESSION
Jérémie Galarneau [Fri, 9 Oct 2020 16:04:10 +0000 (12:04 -0400)] 
Fix: relayd: live: invalid return code on DETACH_SESSION

Babeltrace 2 reports an invalid return code being returned in reply to a

Reviewing the relevant Babeltrace 2 code, the logging can only be
produced if the reception of the lttng_viewer_detach_session_response
structure succeeds.

This elemininated my first guess that this was caused by the relay
daemon closing the socket before sending the reply. In that case, an
invalid status code of '0' could have been erroneously returned as a
status code since the recv() call on the socket would return 0.

It turns out that on a failure to return a packet, viewer_get_packet()
returns an error status code, but also sends a zero-initialized payload
buffer of the size of the requested packet.

This causes live clients which detach following the error of the
GET_PACKET command to interpret the still-enqueued zero-initialized
buffer as a reply to the DETACH_SESSION command. Since zero is not a
valid status code, it is correctly interpreted as a protocol error.

The reply_size is set to the header's size to only transmit the header
when an error reply is sent.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I69ed74f83404a16353d2bdbaa9f3adcdc2a03892

11 months agoTests: clear: remove test workspace directory
Jérémie Galarneau [Thu, 8 Oct 2020 22:15:34 +0000 (18:15 -0400)] 
Tests: clear: remove test workspace directory

The clear tests only removes its workspace's subdirectory, but
leaves an empty directory behind. Remove the wildcard and remove
the root of the workspace on clean-up.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I551f892af5423c6ed5933beb0c1a13f41a30a26e

12 months agoTests: ns_contexts: discarded events result in test failure
Jérémie Galarneau [Mon, 21 Sep 2020 21:24:50 +0000 (17:24 -0400)] 
Tests: ns_contexts: discarded events result in test failure

A follow-up change makes all events emited by gen-ust-events
a bit larger, which causes them to no longer fit in the default
channel configuration's buffers.

This causes the test to fail occasionnaly when the consumer daemon
fails to consume the packets fast enough to leave room in the
buffers for new events.

The test doesn't need to produce 10,000 events; reducing to
1,000 produced events makes no material difference and works
around the problem.

Signed-off-by: Jérémie Galarneau <>
Change-Id: Ie87583bb9bb9cdd813f80443231a65164ef67df1

12 months agoFix: PERROR spam when `tracing` group does not exist
Jérémie Galarneau [Tue, 15 Sep 2020 20:22:14 +0000 (16:22 -0400)] 
Fix: PERROR spam when `tracing` group does not exist

The session daemon prints a PERROR on launch when the tracing group does
not exist. This should not occur when the group simply does not exist as
this is not an error. In that case (ESRCH), a DBG statement is

Signed-off-by: Jérémie Galarneau <>
Change-Id: I3ade29071a8f4e9fe2eb56bf05ff4150b70fd463

12 months agoBuild fix: implicit declaration of function 'PERROR' on Solaris
Jérémie Galarneau [Fri, 11 Sep 2020 03:57:54 +0000 (23:57 -0400)] 
Build fix: implicit declaration of function 'PERROR' on Solaris

Solaris 10/11 CI builds complain that PERROR is not declared
in memstream.h. This addresses the warning on both platforms.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I09ce7cea216e075d0ef7256f738ea7400d193b6b

12 months agotests: unit: event-rule unit testing
Jonathan Rajotte [Thu, 28 Nov 2019 19:19:16 +0000 (14:19 -0500)] 
tests: unit: event-rule unit testing

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Ic25fac00027b9b62c7d9dd060e75228aa7e86c57

12 months agoevent-rule: introduce event rule tracepoint
Jonathan Rajotte [Wed, 11 Mar 2020 17:58:48 +0000 (13:58 -0400)] 
event-rule: introduce event rule tracepoint

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I77495a7b0e359e6f513dfc862dec65b4946d08ba

12 months agoevent-rule: introduce event rule uprobe
Jonathan Rajotte [Wed, 11 Mar 2020 17:56:36 +0000 (13:56 -0400)] 
event-rule: introduce event rule uprobe

This is the "--userspace-probe" option of the enable-event command line.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I43478cb75bd8fdc28e2927d53e0a9a09f2283dea

12 months agoevent-rule: introduce event rule syscall
Jonathan Rajotte [Wed, 11 Mar 2020 17:55:16 +0000 (13:55 -0400)] 
event-rule: introduce event rule syscall

This is the "--syscall" option of the enable-event command line.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I9c36cb0440e1f26a3b436782eb437a8ddffbe4fa

12 months agoevent-rule: introduce event-rule kprobe
Jonathan Rajotte [Wed, 11 Mar 2020 17:52:38 +0000 (13:52 -0400)] 
event-rule: introduce event-rule kprobe

This is the "--probe" option of the enable-event command line.

Change-Id: I6d763df53d5e838ea2266d49b1f22bc23a9addb1
Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
12 months agoevent-rule: lttng_event_rule base object
Jonathan Rajotte [Wed, 11 Mar 2020 17:50:08 +0000 (13:50 -0400)] 
event-rule: lttng_event_rule base object

A lttng_event_rule object is the base object representing an event-rule.

We plan on using the event-rule object for compositing with a new
condition type.

This also paves the way toward further improvement of the lttng_event
related APIs.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I5bbfa3b75337f040cf7e565447d4a4af590ed043

12 months agoIntroduce kernel-probe locations
Jonathan Rajotte [Mon, 24 Aug 2020 19:50:49 +0000 (15:50 -0400)] 
Introduce kernel-probe locations

Kernel probe can be configured by two type of location.

The first one is via address:

The second one is using a symbol name combined with an offset.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Icd280e7a8403c761987472f0a416ef5188a2068d

12 months agouserspace-probe: replace explicit null-termination check
Jérémie Galarneau [Thu, 10 Sep 2020 16:23:28 +0000 (12:23 -0400)] 
userspace-probe: replace explicit null-termination check

Replace explicit null-termination checks by uses of
lttng_buffer_view_contains_string() which provides the same
guarantees and ensures the string pointer is within the view.

Signed-off-by: Jérémie Galarneau <>
Change-Id: If0038a82ad7dfe1ed0e8cdef7870d5e25d62200d

12 months agoRevert "userspace-probe: replace explicit null-termination check"
Jérémie Galarneau [Fri, 11 Sep 2020 15:10:44 +0000 (11:10 -0400)] 
Revert "userspace-probe: replace explicit null-termination check"

This reverts commit b9e63e21bd01c0deeaec2195ba912e38460bc038.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I909339dbdcf4a7931ad95c5b4b6af152aa52487c

12 months agoTests: clean-up: remove trailing dot in snapshot test statements
Jérémie Galarneau [Thu, 10 Sep 2020 16:29:50 +0000 (12:29 -0400)] 
Tests: clean-up: remove trailing dot in snapshot test statements

Signed-off-by: Jérémie Galarneau <>
Change-Id: I95208d67b18ba806f009b9a6b53d5e2cc38b6c74

12 months agouserspace-probe: replace explicit null-termination check
Jérémie Galarneau [Thu, 10 Sep 2020 16:23:28 +0000 (12:23 -0400)] 
userspace-probe: replace explicit null-termination check

Replace explicit null-termination checks by uses of
lttng_buffer_view_contains_string() which provides the same
guarantees and ensures the string pointer is within the view.

Signed-off-by: Jérémie Galarneau <>
Change-Id: If0038a82ad7dfe1ed0e8cdef7870d5e25d62200d

12 months agouserspace-probe: log function name on invalid parameter error
Jérémie Galarneau [Thu, 10 Sep 2020 16:22:59 +0000 (12:22 -0400)] 
userspace-probe: log function name on invalid parameter error

Signed-off-by: Jérémie Galarneau <>
Change-Id: I31bb1e7af0cde85a7ddb4614796cae1da3e5b1b9

12 months agoAllow run-as to generate filter bytecode.
Jonathan Rajotte [Fri, 29 Nov 2019 21:12:28 +0000 (16:12 -0500)] 
Allow run-as to generate filter bytecode.

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I3742bb00b7c753b7d256cdff1889a5e90865608b

12 months agoFix: add missing errno.h in pthread compat
Michael Jeanson [Wed, 26 Aug 2020 18:30:07 +0000 (14:30 -0400)] 
Fix: add missing errno.h in pthread compat

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: Idf574e6e0c7f535693149f3c88f1784188fb14da

12 months agoAdd common util to set thread name
Michael Jeanson [Wed, 12 Aug 2020 21:08:07 +0000 (17:08 -0400)] 
Add common util to set thread name

Use the same code to set all the thread names and fail gracefully on
platforms that don't support them.

This sets the minimum requirement for thread names on Linux to Glibc
>= 2.12, which seems reasonable.

Signed-off-by: Michael Jeanson <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I61c0b9adb6c2309fed91b5a1b11ebc5ee2a637ce

13 months agoFix: liblttng-ctl: unchecked return value on buffer append
Jérémie Galarneau [Fri, 21 Aug 2020 18:28:54 +0000 (14:28 -0400)] 
Fix: liblttng-ctl: unchecked return value on buffer append

Allocation failures can cause lttng_dynamic_buffer_append to fail;
its result should always be checked.

Signed-off-by: Jérémie Galarneau <>
Change-Id: Id1870b1e19d3451afdd1e992355d83d4028b5723

13 months agoFix: action executor: double work list unlock on error
Jérémie Galarneau [Fri, 21 Aug 2020 18:16:10 +0000 (14:16 -0400)] 
Fix: action executor: double work list unlock on error

The action executor executes its queued work items without holding the
work list lock. This can result in a double-unlock when a fatal error
occurs during the processing of a work item.

A check for the "should_quit" flag is added before unlocking since this
is the only other reason for the thread to exit its loop.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I8d6b1a3511174abd08848ac3677cdf8a326fa8c5

13 months agoMove filter related code to libfilter under libcommon
Jonathan Rajotte [Thu, 28 Nov 2019 21:09:16 +0000 (16:09 -0500)] 
Move filter related code to libfilter under libcommon

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I006dcac801ce1ec742de3a03f21a1c5f8b698298

13 months agoClean-up: consumer: consumer_metadata_cache_write is not const-correct
Jérémie Galarneau [Thu, 20 Aug 2020 19:40:10 +0000 (15:40 -0400)] 
Clean-up: consumer: consumer_metadata_cache_write is not const-correct

`data` is used as a source argument and can be marked as `const`.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I9b2b32fe253e1b89a2605ed9c859a04141b321d5

13 months agoFix: memcpy used on potentially overlapping regions
Jérémie Galarneau [Thu, 20 Aug 2020 19:38:18 +0000 (15:38 -0400)] 
Fix: memcpy used on potentially overlapping regions

Caught by reviewing unrelated code, these two uses of memcpy
can operate on overlapping buffers. I checked all other uses
of "raw" memcpy and those appear safe.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I72b1204bc52a92015042adb6a67b022d140f5b4e

13 months agosessiond: notification: use lttng_payload for communications
Jonathan Rajotte [Tue, 14 Jul 2020 18:56:37 +0000 (14:56 -0400)] 
sessiond: notification: use lttng_payload for communications

Allows passing of fds related to object (e.g userspace probes).

Signed-off-by: Jonathan Rajotte <>
Signed-off-by: Jérémie Galarneau <>
Change-Id: I7bb3a91c71016b2939b0e05aca60d57c2da14a20

13 months agoFix: sessiond: client/client_list lock inversion on disconnect
Jérémie Galarneau [Tue, 18 Aug 2020 20:01:30 +0000 (16:01 -0400)] 
Fix: sessiond: client/client_list lock inversion on disconnect

Coverity reports a lock inversion scenario in
handle_notification_thread_client_disconnect() where a client's lock is
held while acquiring the client list lock. This is indeed a problem.

As indicated in the notification_client and notification_client_list
comments, the locking was shoe-horned to make it possible for the action
executor to enqueue notifications in a client's outgoing queue and flush

Since this is the only access pattern that is supported, the client
locking is reworked slightly to only acquire the client lock when
checking the "active" flag, interacting with the outbound communication
state, and sending through a client's socket.

This change makes the client locking regions more narrow which accounts
for the somewhat large number of lines affected.

The updates to the `active` flag on error are moved to the function that
flushes the outbound queue instead of expecting the callers to set it.
This allows the locking to be limited to this function rather than
relying on the callers.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I8632d0f7785ec727dabd329bdfba010fd5e4643a

13 months agoFix: sessiond: missing rcu read lock on client in/out events
Jérémie Galarneau [Mon, 17 Aug 2020 20:55:39 +0000 (16:55 -0400)] 
Fix: sessiond: missing rcu read lock on client in/out events

Users of get_client_from_sock() must hold the RCU read lock
for the duration of the use of the notification_client.

Signed-off-by: Jérémie Galarneau <>
Change-Id: I644e549187ee47c959eeb692e27be111343d8979

13 months agosessiond: enforce user-exclusive session access in session_access_ok
Jérémie Galarneau [Fri, 14 Aug 2020 20:59:18 +0000 (16:59 -0400)] 
sessiond: enforce user-exclusive session access in session_access_ok

The current session_access_ok logic disallows the access to a session
  uid != session->uid && gid != session->gid && uid != 0

This means that any user that is part of the same primary group as the
session's owner can access the session. The primary group is not
necessarily (and most likely) not the `tracing` group. Moreover, the
`tracing` group is not meant to provide shared access to sessions, but
to allow interactions with a root session daemon.

For instance:
  - the session has uid = 1000, gid = 100
  - the current user has uid = 1001, gid = 100

access to the session is granted.

This is way too broad and unexpected from most users as the LTTng
documentation never mentions this "primary group share tracing sessions"
behaviour. The documentation only alludes to the fact that separate
users have "their own set of sessions".

On most distributions, this change will have no impact as `useradd`
creates a new group for every user. Users will never share a primary
group and thus can't control each others' sessions.

However, it is not unusual to have users share a primary group (e.g.
`users`) and set the default umask to `0700`. In that case, there is no
expectation that every user will share files and there would be no
reasonable expectation that they should share all sessions.

For instance, it would be unexpected for one user to tear down the
sessions of other users with a single `lttng destroy -a` command.

If this type of session sharing is desirable to some users, then the
default umask of users could be checked or sessions could be created as
part of a group. However, in doubt, it is preferable to be strict.

This is not marked as a fix since this was most likely deliberate and
the change could, although unlikely, break existing deployment

Signed-off-by: Jérémie Galarneau <>
Change-Id: I98f7ffb29d5f6dcb9d660535c1d3f5a1d1a68293

13 months agosessiond: trigger: run trigger actions through an action executor
Jérémie Galarneau [Tue, 11 Feb 2020 04:29:18 +0000 (23:29 -0500)] 
sessiond: trigger: run trigger actions through an action executor

The `action executor` interface allows the notification subsystem to enqueue
work items to execute on behalf of a given trigger. This allows the notification
thread to remain responsive even if the actions to execute are blocking (as
through the use of network communication).

Before this commit, the notification subsystem only handled `notify` actions;
handling code for new action types are added as part of the action executor.

The existing `notify` action is now performed through the action executor so
that all actions can be managed in the same way.

This is less efficient than sending the notifications directly, but could be
optimized trivially (if it ever becomes a problem) when:
  - the action is a group containing only a `notify` action,
  - the action is a `notify` action.

Overview of changes to existing code

Managing the new action types requires fairly localized changes to the existing
notification subsystem code. The main code paths that are modified are the sites
where `evaluation` objects are created:
  1) on an object state change (session or channel state changes, see
     handle_notification_thread_channel_sample and
  2) on registration of a trigger (see
  3) on subscription to a condition (see client_handle_message_subscription).

To understand the lifetime of most objects involved in a work deferral to the
action executor, see the paragraph in notification-thread-internal.h (line 82)
to understand the relation between clients and client lists.

1) Object state changes

As hinted in the notification_client_list documentation, deferring work on a
state change is straight-forward: a reference is taken on a client list and the
list is provided to the action executor as part of a work item.

Hence, very little changes are made to the the two state-change handling sites
beyond enqueuing a work item rather than directly sending a notification.

2) Subscription to a condition

A notification client can subscribe to a condition before or after a matching
trigger (same condition and containing a notify action) has been registered.

If no matching trigger were registered, no client list exists and there is
nothing to do.

If a matching trigger existed, a client list (which could be empty) will already
exist and the client is simply added to the client list. However, it is
important to evaluate the condition for the client (as the condition could
already be true) and send the notification to that client only and not to all
clients in the list.

Before this change, since everything was done in the same thread, a temporary
list containing only the newly-subscribed client was created on the stack and
the notification was sent/queued immediately. After sending the condition, the
client was removed from the temporary list and added to the "real" client list.

This strategy cannot be used with the action executor as the "temporary" client
list must exist beyond the scope of the function. Moreover, the notification
subsystem assumes that clients are in per-condition client lists and that they
can safely be destroyed when they are not present in any list.

Fortunately, here we know that the action to perform is to `notify` and nothing
else. The enqueuing of the notification is performed "in place" by the
notification thread without deferring to the action executor.

3) Registration of a trigger

When a client subscribes to a condition, the current state of that condition is
immediately evaluated. If the condition is true (for instance, a channel's
buffer are filled beyond X% of their capacity), the action associated with the
trigger is executed right away.

This path requires little changes as a client list is created when a trigger is
registered. Hence, it is possible to use the client list to defer work as is
done in `1`.

4) Trigger registration

Since the `notify` action was the only supported action type, the notification
subsystem always created a client list associated with the new trigger's

This is changed to only perform the creation (and publication) of the client
list if the trigger's action is (or contains, in the case of a group) a `notify`

Signed-off-by: Jérémie Galarneau <>
Change-Id: I43b54b93c1244591aeff6e0d0fa8076c7b5e0c50

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