rtla: Fix parse_cpu_set() bug introduced by strtoi()

The patch 'Replace atoi() with a robust strtoi()' introduced a bug
in parse_cpu_set(), which relies on partial parsing of the input string.

The

rtla: Fix parse_cpu_set() bug introduced by strtoi()

The patch 'Replace atoi() with a robust strtoi()' introduced a bug
in parse_cpu_set(), which relies on partial parsing of the input string.

The function parses CPU specifications like '0-3,5' by incrementing
a pointer through the string. strtoi() rejects strings with trailing
characters, causing parse_cpu_set() to fail on any CPU list with
multiple entries.

Restore the original use of atoi() in parse_cpu_set().

Fixes: 7e9dfccf8f11 ("rtla: Replace atoi() with a robust strtoi()")
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20260112192642.212848-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Fix parse_cpu_set() return value documentation

Correct the return value documentation for parse_cpu_set() function
in utils.c. The comment incorrectly stated that the function returns
1 on suc

rtla: Fix parse_cpu_set() return value documentation

Correct the return value documentation for parse_cpu_set() function
in utils.c. The comment incorrectly stated that the function returns
1 on success and 0 on failure, but the actual implementation returns
0 on success and 1 on failure, following the common error-on-nonzero
convention used throughout the codebase.

This documentation fix ensures that developers reading the code
understand the correct return value semantics and prevents potential
misuse of the function's return value in conditional checks.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-18-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Ensure null termination after read operations in utils.c

Add explicit null termination and buffer initialization for read()
operations in procfs_is_workload_pid() and get_self_cgroup() functio

rtla: Ensure null termination after read operations in utils.c

Add explicit null termination and buffer initialization for read()
operations in procfs_is_workload_pid() and get_self_cgroup() functions.
The read() system call does not null-terminate the data it reads, and
when the buffer is filled to capacity, subsequent string operations
will read past the buffer boundary searching for a null terminator.

In procfs_is_workload_pid(), explicitly set buffer[MAX_PATH-1] to '\0'
to ensure the buffer is always null-terminated before passing it to
strncmp(). In get_self_cgroup(), use memset() to zero the path buffer
before reading, which ensures null termination when retval is less than
MAX_PATH. Additionally, set path[MAX_PATH-1] to '\0' after the read to
handle the case where the buffer is filled completely.

These defensive buffer handling practices prevent potential buffer
overruns and align with the ongoing buffer safety improvements across
the rtla codebase.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-17-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Make stop_tracing variable volatile

The stop_tracing global variable is accessed from both the signal
handler context and the main program flow without synchronization.
This creates a potentia

rtla: Make stop_tracing variable volatile

The stop_tracing global variable is accessed from both the signal
handler context and the main program flow without synchronization.
This creates a potential race condition where compiler optimizations
could cache the variable value in registers, preventing the signal
handler's updates from being visible to other parts of the program.

Add the volatile qualifier to stop_tracing in both common.c and
common.h to ensure all accesses to this variable bypass compiler
optimizations and read directly from memory. This guarantees that
when the signal handler sets stop_tracing, the change is immediately
visible to the main program loop, preventing potential hangs or
delayed shutdown when termination signals are received.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-16-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Add generated output files to gitignore

The rtla tool generates various output files during testing and
execution, including custom trace outputs and histogram data. These
files are artifacts

rtla: Add generated output files to gitignore

The rtla tool generates various output files during testing and
execution, including custom trace outputs and histogram data. These
files are artifacts of running the tool with different options and
should not be tracked in version control.

Add gitignore entries for custom_filename.txt, osnoise_irq_noise_hist.txt,
osnoise_trace.txt, and timerlat_trace.txt to prevent accidentally
committing these generated files. This aligns with the existing pattern
of ignoring build artifacts and generated headers like *.skel.h.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-15-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Fix NULL pointer dereference in actions_parse

The actions_parse() function uses strtok() to tokenize the trigger
string, but does not check if the returned token is NULL before
passing it to s

rtla: Fix NULL pointer dereference in actions_parse

The actions_parse() function uses strtok() to tokenize the trigger
string, but does not check if the returned token is NULL before
passing it to strcmp(). If the trigger parameter is an empty string
or contains only delimiter characters, strtok() returns NULL, causing
strcmp() to dereference a NULL pointer and crash the program.

This issue can be triggered by malformed user input or edge cases in
trigger string parsing. Add a NULL check immediately after the strtok()
call to validate that a token was successfully extracted before using
it. If no token is found, the function now returns -1 to indicate a
parsing error.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-13-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Remove unused headers

Remove unused includes for <errno.h> and <signal.h> to clean up the
code and reduce unnecessary dependencies.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Lin

rtla: Remove unused headers

Remove unused includes for <errno.h> and <signal.h> to clean up the
code and reduce unnecessary dependencies.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-12-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Remove redundant memset after calloc

The actions struct is allocated using calloc, which already returns
zeroed memory. The subsequent memset call to zero the 'present' member
is therefore red

rtla: Remove redundant memset after calloc

The actions struct is allocated using calloc, which already returns
zeroed memory. The subsequent memset call to zero the 'present' member
is therefore redundant.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-10-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Use standard exit codes for result enum

The result enum defines custom values for PASSED, ERROR, and FAILED.
These values correspond to standard exit codes EXIT_SUCCESS and
EXIT_FAILURE.

Upda

rtla: Use standard exit codes for result enum

The result enum defines custom values for PASSED, ERROR, and FAILED.
These values correspond to standard exit codes EXIT_SUCCESS and
EXIT_FAILURE.

Update the enum to use the standard macros EXIT_SUCCESS and
EXIT_FAILURE to improve readability and adherence to standard C
practices.

The FAILED value is implicitly assigned EXIT_FAILURE + 1, so there
is no need to assign an explicit value.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-9-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Replace atoi() with a robust strtoi()

The atoi() function does not perform error checking, which can lead to
undefined behavior when parsing invalid or out-of-range strings. This
can cause iss

rtla: Replace atoi() with a robust strtoi()

The atoi() function does not perform error checking, which can lead to
undefined behavior when parsing invalid or out-of-range strings. This
can cause issues when parsing user-provided numerical inputs, such as
signal numbers, PIDs, or CPU lists.

To address this, introduce a new strtoi() helper function that safely
converts a string to an integer. This function validates the input and
checks for overflows, returning a negative value on failure.

Replace all calls to atoi() with the new strtoi() function and add
proper error handling to make the parsing more robust and prevent
potential issues.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-5-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla: Introduce for_each_action() helper

The for loop to iterate over the list of actions is used in
more than one place. To avoid code duplication and improve
readability, introduce a for_each_acti

rtla: Introduce for_each_action() helper

The for loop to iterate over the list of actions is used in
more than one place. To avoid code duplication and improve
readability, introduce a for_each_action() helper macro.

Replace the open-coded for loops with the new helper.

Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-4-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Deduplicate cgroup path opening code

Both set_pid_cgroup() and set_comm_cgroup() functions contain
identical code for opening the cgroup.procs file.

Extract this common code into a new

tools/rtla: Deduplicate cgroup path opening code

Both set_pid_cgroup() and set_comm_cgroup() functions contain
identical code for opening the cgroup.procs file.

Extract this common code into a new helper function open_cgroup_procs()
to reduce code duplication and improve maintainability.

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251224125058.1771519-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -H/--house-keeping option parsing

Each rtla tool duplicates parsing of -H/--house-keeping.

Migrate the option parsing from individual tools to the
common_parse_options().

S

tools/rtla: Consolidate -H/--house-keeping option parsing

Each rtla tool duplicates parsing of -H/--house-keeping.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-8-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -P/--priority option parsing

Each rtla tool duplicates parsing of -P/--priority.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-

tools/rtla: Consolidate -P/--priority option parsing

Each rtla tool duplicates parsing of -P/--priority.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-7-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -e/--event option parsing

Each rtla tool duplicates parsing of -e/--event.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Co

tools/rtla: Consolidate -e/--event option parsing

Each rtla tool duplicates parsing of -e/--event.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-6-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -d/--duration option parsing

Each rtla tool duplicates parsing of -d/--duration.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-

tools/rtla: Consolidate -d/--duration option parsing

Each rtla tool duplicates parsing of -d/--duration.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-5-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -D/--debug option parsing

Each rtla tool duplicates parsing of -D/--debug.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Co

tools/rtla: Consolidate -D/--debug option parsing

Each rtla tool duplicates parsing of -D/--debug.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-4-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -C/--cgroup option parsing

Each rtla tool duplicates parsing of -C/--cgroup.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by:

tools/rtla: Consolidate -C/--cgroup option parsing

Each rtla tool duplicates parsing of -C/--cgroup.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-3-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Consolidate -c/--cpus option parsing

Each rtla tool duplicates parsing of -c/--cpus.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Cost

tools/rtla: Consolidate -c/--cpus option parsing

Each rtla tool duplicates parsing of -c/--cpus.

Migrate the option parsing from individual tools to the
common_parse_options().

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Add common_parse_options()

Each rtla tool duplicates parsing of many common options. This creates
maintenance overhead and risks inconsistencies when updating these
options.

Add common_

tools/rtla: Add common_parse_options()

Each rtla tool duplicates parsing of many common options. This creates
maintenance overhead and risks inconsistencies when updating these
options.

Add common_parse_options() to centralize parsing of options used across
all tools.

Common options to be migrated in future patches.

Changes since v1:
- restore opterr

Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla/tests: Run Test::Harness in verbose mode

Add -v flag to prove command to also print the names of tests that
succeeded, not only those that failed, to allow easier debugging of the
test suite.

rtla/tests: Run Test::Harness in verbose mode

Add -v flag to prove command to also print the names of tests that
succeeded, not only those that failed, to allow easier debugging of the
test suite.

Also, drop printing the option and value to stdout in
check_with_osnoise_options, which was a debugging print that was
accidentally left in the final commit, and which would be otherwise now
visible in make check output, as stdout is no longer suppressed.

Suggested-by: Crystal Wood <crwood@redhat.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20251126144205.331954-6-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla/tests: Test BPF action program

Add a test that implements a BPF program writing to a test map, which
is attached to RTLA via --bpf-action to be executed on theshold
overflow.

A combination of

rtla/tests: Test BPF action program

Add a test that implements a BPF program writing to a test map, which
is attached to RTLA via --bpf-action to be executed on theshold
overflow.

A combination of --on-threshold shell with bpftool (which is always
present if BPF support is enabled) is used to check whether the BPF
program has executed successfully.

Suggested-by: Crystal Wood <crwood@redhat.com>
Link: https://lore.kernel.org/r/20251126144205.331954-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla/timerlat: Add example for BPF action program

Add an example BPF action program that prints the measured latency to
the tracefs buffer via bpf_printk().

A new Makefile target, "examples", is ad

rtla/timerlat: Add example for BPF action program

Add an example BPF action program that prints the measured latency to
the tracefs buffer via bpf_printk().

A new Makefile target, "examples", is added to build the example. In
addition, "sample/" subfolder is renamed to "example".

If BPF skeleton support is unavailable or disabled, a warning will be
displayed when building the BPF action program example.

Link: https://lore.kernel.org/r/20251126144205.331954-4-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla/timerlat: Add --bpf-action option

Add option --bpf-action that allows the user to attach an external BPF
program that will be executed via BPF tail call on latency threshold
overflow.

Executin

rtla/timerlat: Add --bpf-action option

Add option --bpf-action that allows the user to attach an external BPF
program that will be executed via BPF tail call on latency threshold
overflow.

Executing additional BPF code on latency threshold overflow allows doing
low-latency and in-kernel troubleshooting of the cause of the overflow.

The option takes an argument, which is a path to a BPF ELF file
expected to contain a function named "action_handler" in a section named
"tp/timerlat_action" (the section is necessary for libbpf to assign the
correct BPF program type to it).

Link: https://lore.kernel.org/r/20251126144205.331954-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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rtla/timerlat: Support tail call from BPF program

Add a map to the rtla-timerlat BPF program that holds a file descriptor
of another BPF program, to be executed on threshold overflow.

timerlat_bpf_

rtla/timerlat: Support tail call from BPF program

Add a map to the rtla-timerlat BPF program that holds a file descriptor
of another BPF program, to be executed on threshold overflow.

timerlat_bpf_set_action() is added as an interface to set the program.

Link: https://lore.kernel.org/r/20251126144205.331954-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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