kernel/linux.git/tools/tracing/rtla/src/utils.c, branch v7.0-rc7

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

2026-01-13T07:32:52+00:00

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 Reviewed-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20260112192642.212848-2-costa.shul@redhat.com Signed-off-by: Tomas Glozar

rtla: Fix parse_cpu_set() return value documentation

2026-01-07T14:57:56+00:00

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 Link: https://lore.kernel.org/r/20260106133655.249887-18-wander@redhat.com Signed-off-by: Tomas Glozar

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

2026-01-07T14:57:56+00:00

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 Link: https://lore.kernel.org/r/20260106133655.249887-17-wander@redhat.com Signed-off-by: Tomas Glozar

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

2026-01-07T14:57:55+00:00

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 Link: https://lore.kernel.org/r/20260106133655.249887-5-wander@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Deduplicate cgroup path opening code

2026-01-07T14:57:38+00:00

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

rtla: Fix -C/--cgroup interface

2025-11-21T09:30:27+00:00

Currently, user can only specify cgroup to the tracer's thread the following ways: `-C[cgroup]` `-C[=cgroup]` `--cgroup[=cgroup]` If user tries to specify cgroup as `-C [cgroup]` or `--cgroup [cgroup]`, the parser silently fails and rtla's cgroup is used for the tracer threads. To make interface more user-friendly, allow user to specify cgroup in the aforementioned way, i.e. `-C [cgroup]` and `--cgroup [cgroup]`. Refactor identical logic between -t/--trace and -C/--cgroup into a common function. Change documentation to reflect this user interface change. Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Ivan Pravdin Reviewed-by: Tomas Glozar Link: https://lore.kernel.org/r/16132f1565cf5142b5fbd179975be370b529ced7.1762186418.git.ipravdin.official@gmail.com [ use capital letter in subject, as required by tracing subsystem ] Signed-off-by: Tomas Glozar

tools/rtla: Add fatal() and replace error handling pattern

2025-11-21T09:30:27+00:00

The code contains some technical debt in error handling, which complicates the consolidation of duplicated code. Introduce an fatal() function to replace the common pattern of err_msg() followed by exit(EXIT_FAILURE), reducing the length of an already long function. Further patches using fatal() follow. Signed-off-by: Costa Shulyupin Reviewed-by: Tomas Glozar Link: https://lore.kernel.org/r/20251011082738.173670-2-costa.shul@redhat.com Signed-off-by: Tomas Glozar

rtla: Define __NR_sched_setattr for LoongArch

2025-05-07T20:35:31+00:00

When executing "make -C tools/tracing/rtla" on LoongArch, there exists the following error: src/utils.c:237:24: error: '__NR_sched_setattr' undeclared Just define __NR_sched_setattr for LoongArch if not exist. Link: https://lore.kernel.org/20250422074917.25771-1-yangtiezhu@loongson.cn Reported-by: Haiyong Sun Signed-off-by: Tiezhu Yang Signed-off-by: Steven Rostedt (Google)

rtla/utils: Add idle state disabling via libcpupower

2024-10-17T21:13:15+00:00

Add functions to utils.c to disable idle states through functions of libcpupower. This will serve as the basis for disabling idle states per cpu when running timerlat. Link: https://lore.kernel.org/20241017140914.3200454-4-tglozar@redhat.com Signed-off-by: Tomas Glozar Signed-off-by: Steven Rostedt (Google)

tools/rtla: fix collision with glibc sched_attr/sched_set_attr

2024-10-11T00:31:48+00:00

glibc commit 21571ca0d703 ("Linux: Add the sched_setattr and sched_getattr functions") now also provides 'struct sched_attr' and sched_setattr() which collide with the ones from rtla. In file included from src/trace.c:11: src/utils.h:49:8: error: redefinition of ‘struct sched_attr’ 49 | struct sched_attr { | ^~~~~~~~~~ In file included from /usr/include/bits/sched.h:60, from /usr/include/sched.h:43, from /usr/include/tracefs/tracefs.h:10, from src/trace.c:4: /usr/include/linux/sched/types.h:98:8: note: originally defined here 98 | struct sched_attr { | ^~~~~~~~~~ Define 'struct sched_attr' conditionally, similar to what strace did: https://lore.kernel.org/all/20240930222913.3981407-1-raj.khem@gmail.com/ and rename rtla's version of sched_setattr() to avoid collision. Link: https://lore.kernel.org/8088f66a7a57c1b209cd8ae0ae7c336a7f8c930d.1728572865.git.jstancek@redhat.com Signed-off-by: Jan Stancek Signed-off-by: Steven Rostedt (Google)