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12 daysMerge tag 'trace-rtla-v7.1' of ↵Linus Torvalds-402/+721
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull RTLA updates from Steven Rostedt: - Simplify option parsing Auto-generate getopt_long() optstring for short options from long options array, avoiding the need to specify it manually and reducing the surface for mistakes. - Add unit tests Implement unit tests (make unit-tests) using libcheck, next to existing runtime tests (make check). Currently, three functions from utils.c are tested. - Add --stack-format option In addition to stopping stack pointer decoding (with -s/--stack option) on first unresolvable pointer, allow also skipping unresolvable pointers and displaying everything, configurable with a new option. - Unify number of CPUs into one global variable Use one global variable, nr_cpus, to store the number of CPUs instead of retrieving it and passing it at multiple places. - Fix behavior in various corner cases Make RTLA behave correctly in several corner cases: memory allocation failure, invalid value read from kernel side, thread creation failure, malformed time value input, and read/write failure or interruption by signal. - Improve string handling Simplify several places in the code that handle strings, including parsing of action arguments. A few new helper functions and variables are added for that purpose. - Get rid of magic numbers Few places handling paths use a magic number of 1024. Replace it with MAX_PATH and ARRAY_SIZE() macro. - Unify threshold handling Code that handles response to latency threshold is duplicated between tools, which has led to bugs in the past. Unify it into a new helper as much as possible. - Fix segfault on SIGINT during cleanup The SIGINT handler touches dynamically allocated memory. Detach it before freeing it during cleanup to prevent segmentation fault and discarding of output buffers. Also, properly document SIGINT handling while at it. * tag 'trace-rtla-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (28 commits) Documentation/rtla: Document SIGINT behavior rtla: Fix segfault on multiple SIGINTs rtla/utils: Fix loop condition in PID validation rtla/utils: Fix resource leak in set_comm_sched_attr() rtla/trace: Fix I/O handling in save_trace_to_file() rtla/trace: Fix write loop in trace_event_save_hist() rtla/timerlat: Simplify RTLA_NO_BPF environment variable check rtla: Use str_has_prefix() for option prefix check rtla: Enforce exact match for time unit suffixes rtla: Use str_has_prefix() for prefix checks rtla: Add str_has_prefix() helper function rtla: Handle pthread_create() failure properly rtla/timerlat: Add bounds check for softirq vector rtla: Simplify code by caching string lengths rtla: Replace magic number with MAX_PATH rtla: Introduce common_threshold_handler() helper rtla/actions: Simplify argument parsing rtla: Use strdup() to simplify code rtla: Exit on memory allocation failures during initialization tools/rtla: Remove unneeded nr_cpus from for_each_monitored_cpu ...
2026-03-30rtla: Fix build without libbpf headerTomas Glozar-1/+0
rtla supports building without libbpf. However, BPF actions patchset [1] adds an include of bpf/libbpf.h into timerlat_bpf.h, which breaks build on systems that don't have libbpf headers installed. This is a leftover from a draft version of the patchset where timerlat_bpf_set_action() (which takes a struct bpf_program * argument) was defined in the header. timerlat_bpf.c already includes bpf/libbpf.h via timerlat.skel.h when libbpf is present. Remove the redundant include to fix build on systems without libbpf headers. [1] https://lore.kernel.org/linux-trace-kernel/20251126144205.331954-1-tglozar@redhat.com/T/ Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Crystal Wood <crwood@redhat.com> Cc: Costa Shulyupin <costa.shul@redhat.com> Link: https://patch.msgid.link/20260330091207.16184-1-tglozar@redhat.com Reported-by: Steven Rostedt (Google) <rostedt@goodmis.org> Closes: https://lore.kernel.org/linux-trace-kernel/20260329122202.65a8b575@robin/ Fixes: 8cd0f08ac72e ("rtla/timerlat: Support tail call from BPF program") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Reviewed-by: Wander Lairson Costa <wander@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2026-03-20rtla: Fix segfault on multiple SIGINTsTomas Glozar-1/+15
Detach stop_trace() from SIGINT/SIGALRM on tool clean-up to prevent it from crashing RTLA by accessing freed memory. This prevents a crash when multiple SIGINTs are received. Fixes: d6899e560366 ("rtla/timerlat_hist: Abort event processing on second signal") Fixes: 80967b354a76 ("rtla/timerlat_top: Abort event processing on second signal") Reviewed-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260310160725.144443-1-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/utils: Fix loop condition in PID validationWander Lairson Costa-1/+1
The procfs_is_workload_pid() function iterates through a directory entry name to validate if it represents a process ID. The loop condition checks if the pointer t_name is non-NULL, but since incrementing a pointer never makes it NULL, this condition is always true within the loop's context. Although the inner isdigit() check catches the NUL terminator and breaks out of the loop, the condition is semantically misleading and not idiomatic for C string processing. Correct the loop condition from checking the pointer (t_name) to checking the character it points to (*t_name). This ensures the loop terminates when the NUL terminator is reached, aligning with standard C string iteration practices. While the original code functioned correctly due to the existing character validation, this change improves code clarity and maintainability. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-19-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/utils: Fix resource leak in set_comm_sched_attr()Wander Lairson Costa-5/+6
The set_comm_sched_attr() function opens the /proc directory via opendir() but fails to call closedir() on its successful exit path. If the function iterates through all processes without error, it returns 0 directly, leaking the DIR stream pointer. Fix this by refactoring the function to use a single exit path. A retval variable is introduced to track the success or failure status. All exit points now jump to a unified out label that calls closedir() before the function returns, ensuring the resource is always freed. Fixes: dada03db9bb19 ("rtla: Remove procps-ng dependency") Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-18-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/trace: Fix I/O handling in save_trace_to_file()Wander Lairson Costa-7/+24
The read/write loop in save_trace_to_file() does not correctly handle errors from the read() and write() system calls. If either call is interrupted by a signal, it returns -1 with errno set to EINTR, but the code treats this as a fatal error and aborts the save operation. Additionally, write() may perform a partial write, returning fewer bytes than requested, which the code does not handle. Fix the I/O loop by introducing proper error handling. The return value of read() is now stored in a ssize_t variable and checked for errors, with EINTR causing a retry. For write(), an inner loop ensures all bytes are written, handling both EINTR and partial writes. Error messages now include strerror() output for better debugging. This follows the same pattern established in the previous commit that fixed trace_event_save_hist(), ensuring consistent and robust I/O handling throughout the trace saving code. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-17-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/trace: Fix write loop in trace_event_save_hist()Wander Lairson Costa-3/+11
The write loop in trace_event_save_hist() does not correctly handle errors from the write() system call. If write() returns -1, this value is added to the loop index, leading to an incorrect memory access on the next iteration and potentially an infinite loop. The loop also fails to handle EINTR. Fix the write loop by introducing proper error handling. The return value of write() is now stored in a ssize_t variable and checked for errors. The loop retries the call if interrupted by a signal and breaks on any other error after logging it with strerror(). Additionally, change the index variable type from int to size_t to match the type used for buffer sizes and by strlen(), improving type safety. Fixes: 761916fd02c2 ("rtla/trace: Save event histogram output to a file") Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-16-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/timerlat: Simplify RTLA_NO_BPF environment variable checkWander Lairson Costa-1/+2
The code that checks the RTLA_NO_BPF environment variable calls getenv() twice and uses strncmp() with a length of 2 to compare against the single-character string "1". This is inefficient and the comparison length is unnecessarily long. Store the result of getenv() in a local variable to avoid the redundant call, and replace strncmp() with strncmp_static() for the exact match comparison. This follows the same pattern established in recent commits that improved string comparison consistency throughout the rtla codebase. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-15-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla: Use str_has_prefix() for option prefix checkWander Lairson Costa-2/+2
The argument parsing code in timerlat_main() and osnoise_main() uses strncmp() with a length of 1 to check if the first argument starts with a dash, indicating an option flag was passed. Replace this pattern with str_has_prefix() for consistency with the rest of the codebase. While character comparison would be slightly more efficient, using str_has_prefix() provides better readability and maintains a uniform coding style throughout the rtla tool. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-14-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla: Enforce exact match for time unit suffixesWander Lairson Costa-4/+19
The parse_ns_duration() function currently uses prefix matching for detecting time units. This approach is problematic as it silently accepts malformed strings such as "100nsx" or "100us_invalid" by ignoring the trailing characters, leading to potential configuration errors. Introduce a match_time_unit() helper that checks the suffix matches exactly and is followed by either end-of-string or a ':' delimiter. The ':' is needed because parse_ns_duration() is also called from get_long_ns_after_colon() when parsing SCHED_DEADLINE priority specifications in the format "d:runtime:period" (e.g., "d:10ms:100ms"). A plain strcmp() would reject valid deadline strings because the suffix "ms" is followed by ":100ms", not end-of-string. Similarly, strncmp_static() would fail because ARRAY_SIZE() includes the NUL terminator, making it equivalent to strcmp() for this comparison. The match_time_unit() helper solves both problems: it rejects malformed input like "100msx" while correctly handling the colon-delimited deadline format. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-13-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla: Use str_has_prefix() for prefix checksWander Lairson Costa-5/+3
The code currently uses strncmp() combined with strlen() to check if a string starts with a specific prefix. This pattern is verbose and prone to errors if the length does not match the prefix string. Replace this pattern with the str_has_prefix() helper function in both trace.c and utils.c. This improves code readability and safety by handling the prefix length calculation automatically. In addition, remove the unused retval variable from trace_event_save_hist() in trace.c to clean up the function and silence potential compiler warnings. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-12-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla: Add str_has_prefix() helper functionWander Lairson Costa-0/+13
Add a str_has_prefix() helper function that tests whether a string starts with a given prefix. This function provides a cleaner interface for prefix matching compared to using strncmp() with strlen() directly. The function returns a boolean value indicating whether the string starts with the specified prefix. This helper will be used in subsequent changes to simplify prefix matching code throughout rtla. Also add the missing string.h include which is needed for the strlen() and strncmp() functions used by str_has_prefix() and the existing strncmp_static() macro. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-11-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla: Handle pthread_create() failure properlyWander Lairson Costa-1/+3
Add proper error handling when pthread_create() fails to create the timerlat user-space dispatcher thread. Previously, the code only logged an error message but continued execution, which could lead to undefined behavior when the tool later expects the thread to be running. When pthread_create() returns an error, the function now jumps to the out_trace error path to properly clean up resources and exit. This ensures consistent error handling and prevents the tool from running in an invalid state without the required user-space thread. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-10-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-11rtla/timerlat: Add bounds check for softirq vectorWander Lairson Costa-2/+2
Add bounds checking when accessing the softirq_name array using the vector value from kernel trace data. The vector field from the osnoise:softirq_noise event is used directly as an array index without validation, which could cause an out-of-bounds read if the kernel provides an unexpected vector value. The softirq_name array contains 10 elements corresponding to the standard Linux softirq vectors. While the kernel should only provide valid vector values in the range 0-9, defensive programming requires validating untrusted input before using it as an array index. If an out-of-range vector is encountered, display the word UNKNOWN instead of attempting to read beyond the array bounds. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-9-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla: Simplify code by caching string lengthsWander Lairson Costa-6/+11
Simplify trace_event_save_hist() and set_comm_cgroup() by computing string lengths once and storing them in local variables, rather than calling strlen() multiple times on the same unchanged strings. This makes the code clearer by eliminating redundant function calls and improving readability. In trace_event_save_hist(), the write loop previously called strlen() on the hist buffer twice per iteration for both the size calculation and loop condition. Store the length in hist_len before entering the loop. In set_comm_cgroup(), strlen() was called on cgroup_path up to three times in succession. Store the result in cg_path_len to use in both the offset calculation and size parameter for subsequent append operations. This simplification makes the code easier to read and maintain without changing program behavior. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-7-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla: Replace magic number with MAX_PATHWander Lairson Costa-13/+13
The trace functions use a buffer to manipulate strings that will be written to tracefs files. These buffers are defined with a magic number of 1024, which is a common source of vulnerabilities. Replace the magic number 1024 with the MAX_PATH macro to make the code safer and more readable. While at it, replace other instances of the magic number with ARRAY_SIZE() when the buffer is locally defined. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-6-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla: Introduce common_threshold_handler() helperWander Lairson Costa-44/+86
Several functions duplicate the logic for handling threshold actions. When a threshold is reached, these functions stop the trace, perform configured actions, and restart the trace if --on-threshold continue is set. Create common_threshold_handler() to centralize this shared logic and avoid code duplication. The function executes the configured threshold actions and restarts the necessary trace instances when appropriate. Also add should_continue_tracing() helper to encapsulate the check for whether tracing should continue after a threshold event, improving code readability at call sites. In timerlat_top_bpf_main_loop(), use common_params directly instead of casting through timerlat_params when only common fields are needed. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-5-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla/actions: Simplify argument parsingWander Lairson Costa-15/+52
The actions_parse() function uses open-coded logic to extract arguments from a string. This includes manual length checks and strncmp() calls, which can be verbose and error-prone. To simplify and improve the robustness of argument parsing, introduce a new extract_arg() helper macro. This macro extracts the value from a "key=value" pair, making the code more concise and readable. Also, introduce STRING_LENGTH() and strncmp_static() macros to perform compile-time calculations of string lengths and safer string comparisons. Refactor actions_parse() to use these new helpers, resulting in cleaner and more maintainable code. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-4-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla: Use strdup() to simplify codeWander Lairson Costa-4/+2
The actions_add_trace_output() and actions_add_shell() functions were using calloc() followed by strcpy() to allocate and copy a string. This can be simplified by using strdup(), which allocates memory and copies the string in a single step. Replace the calloc() and strcpy() calls with strdup(), making the code more concise and readable. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-3-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-10rtla: Exit on memory allocation failures during initializationWander Lairson Costa-132/+108
Most memory allocations in rtla happen during early initialization before any resources are acquired that would require cleanup. In these cases, propagating allocation errors just adds complexity without any benefit. There's nothing to clean up, and the program must exit anyway. This patch introduces fatal allocation wrappers (calloc_fatal, reallocarray_fatal, strdup_fatal) that call fatal() on allocation failure. These wrappers simplify the code by eliminating unnecessary error propagation paths. The patch converts early allocations to use these wrappers in actions_init() and related action functions, osnoise_context_alloc() and osnoise_init_tool(), trace_instance_init() and trace event functions, and parameter structure allocations in main functions. This simplifies the code while maintaining the same behavior: immediate exit on allocation failure during initialization. Allocations that require cleanup, such as those in histogram allocation functions with goto cleanup paths, are left unchanged and continue to return errors. Signed-off-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260309195040.1019085-2-wander@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-09tools/rtla: Remove unneeded nr_cpus from for_each_monitored_cpuCosta Shulyupin-21/+20
nr_cpus does not change at runtime, so passing it through the macro argument is unnecessary. Remove the argument and use the global nr_cpus instead. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Link: https://lore.kernel.org/r/20260306194953.2511960-5-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-09tools/rtla: Remove unneeded nr_cpus membersCosta Shulyupin-50/+38
nr_cpus does not change at runtime, so keeping it in struct members is unnecessary. Use the global nr_cpus instead of struct members. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Link: https://lore.kernel.org/r/20260306194953.2511960-4-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-09tools/rtla: Remove unneeded nr_cpus argumentsCosta Shulyupin-51/+34
nr_cpus does not change at runtime, so passing it through function arguments is unnecessary. Use the global nr_cpus instead of propagating it via parameters. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Link: https://lore.kernel.org/r/20260306194953.2511960-3-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-09tools/rtla: Consolidate nr_cpus usage across all toolsCosta Shulyupin-62/+31
sysconf(_SC_NPROCESSORS_CONF) (via get_nprocs_conf) reflects cpu_possible_mask, which is fixed at boot time, so querying it repeatedly is unnecessary. Replace multiple calls to sysconf(_SC_NPROCESSORS_CONF) with a single global nr_cpus variable initialized once at startup. `#pragma once` in timerlat_u.h is needed for pre-C23 compilers to avoid redefinition errors. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Link: https://lore.kernel.org/r/20260306194953.2511960-2-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-04rtla/timerlat: Add --stack-format optionTomas Glozar-9/+77
In the current implementation, the auto-analysis code for printing the stack captured in the tracefs buffer of the aa instance stops at the first encountered address that cannot be resolved into a function symbol. This is not always the desired behavior on all platforms; sometimes, there might be resolvable entries after unresolvable ones, and sometimes, the user might want to inspect the raw pointers for the unresolvable entries. Add a new option, --stack-format, with three values: - truncate: stop at first unresolvable entry. This is the current behavior, and is kept as the default. - skip: skip unresolvable entries, but do not stop on them. - full: print all entries, including unresolvable ones. To make this work, the "size" field of the stack entry is now also read and used as the maximum number of entries to print, capped at 64, since that is the fixed length of the "caller" field. Link: https://lore.kernel.org/r/20260119115222.744150-1-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-04tools/rtla: Add unit tests for utils.cCosta Shulyupin-0/+157
Add unit tests for utility functions in src/utils.c using the Check testing framework. The tests verify parse_cpu_set(), strtoi(), and parse_prio() functions. Unit tests are built conditionally when libcheck is available. Run tests with 'make unit-test'. The test framework uses the Check library which provides process isolation for each test, preventing failures in one test from affecting others. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Link: https://lore.kernel.org/r/20260119105857.797498-3-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-03-02tools/rtla: Generate optstring from long optionsCosta Shulyupin-9/+37
getopt_long() processes short and long options independently. RTLA, like the majority of applications, uses both short and long variants for each logical option. Since the val member of struct option holds the letter of the short variant, the string of short options can be reconstructed from the array of long options. Add getopt_auto() to generate optstring from an array of long options, eliminating the need to maintain separate short option strings. Signed-off-by: Costa Shulyupin <costa.shul@redhat.com> Reviewed-by: Wander Lairson Costa <wander@redhat.com> Link: https://lore.kernel.org/r/20260108095011.2115719-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com>
2026-01-13rtla: Fix parse_cpu_set() bug introduced by strtoi()Costa Shulyupin-6/+4
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>
2026-01-07rtla: Fix parse_cpu_set() return value documentationWander Lairson Costa-1/+1
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>
2026-01-07rtla: Ensure null termination after read operations in utils.cWander Lairson Costa-0/+3
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>
2026-01-07rtla: Make stop_tracing variable volatileWander Lairson Costa-2/+2
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>
2026-01-07rtla: Add generated output files to gitignoreWander Lairson Costa-0/+4
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>
2026-01-07rtla: Fix NULL pointer dereference in actions_parseWander Lairson Costa-0/+2
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>
2026-01-07rtla: Remove unused headersWander Lairson Costa-4/+0
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>
2026-01-07rtla: Remove redundant memset after callocWander Lairson Costa-2/+0
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>
2026-01-07rtla: Use standard exit codes for result enumWander Lairson Costa-3/+4
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>
2026-01-07rtla: Replace atoi() with a robust strtoi()Wander Lairson Costa-8/+41
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>
2026-01-07rtla: Introduce for_each_action() helperWander Lairson Costa-2/+9
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>
2026-01-07tools/rtla: Deduplicate cgroup path opening codeCosta Shulyupin-33/+32
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>
2026-01-07tools/rtla: Consolidate -H/--house-keeping option parsingCosta Shulyupin-33/+11
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>
2026-01-07tools/rtla: Consolidate -P/--priority option parsingCosta Shulyupin-33/+11
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>
2026-01-07tools/rtla: Consolidate -e/--event option parsingCosta Shulyupin-52/+16
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>
2026-01-07tools/rtla: Consolidate -d/--duration option parsingCosta Shulyupin-29/+11
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>
2026-01-07tools/rtla: Consolidate -D/--debug option parsingCosta Shulyupin-21/+9
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>
2026-01-07tools/rtla: Consolidate -C/--cgroup option parsingCosta Shulyupin-25/+10
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>
2026-01-07tools/rtla: Consolidate -c/--cpus option parsingCosta Shulyupin-33/+11
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>
2026-01-07tools/rtla: Add common_parse_options()Costa Shulyupin-0/+48
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>
2026-01-07rtla/tests: Run Test::Harness in verbose modeTomas Glozar-2/+1
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>
2026-01-07rtla/tests: Test BPF action programTomas Glozar-2/+48
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>
2026-01-07rtla/timerlat: Add example for BPF action programTomas Glozar-1/+24
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>