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A later commit will apply a filter to events recorded to the trace
output. To prevent any user confusion, remove pre-existing filters when
enabling an event provided via the '-e' command line argument.
Suggested-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20260902123942.695822-8-vschneid@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Events are processed in LIFO order for ease of internal processing, but
this is can be confusing to users if the processing ordering is exposed to
them.
A following commit will do just that by making it so the last-defined event
options (filters/triggers) overrides any previous options for that same
event. Thus, process the events in the user-defined order.
Signed-off-by: Valentin Schneider <vschneid@redhat.com>
Link: https://lore.kernel.org/r/20260902123942.695822-7-vschneid@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The "cpu" field of trace entries processed by rtla in tracefs mode is
used as an index into an array of size nr_cpus. In case the cpu numbers
mismatch because either the kernel or rtla reporting the number
incorrectly, out-of-bounds read/write may occur.
Guard against this by dropping trace entries with cpu >= nr_cpus in
collect_registered_events(). A new counter, "invalid_events", is added
to struct trace_instance, and printed (if non zero) next to the
pre-existing missed events counter.
Link: https://lore.kernel.org/r/20260814135511.2207190-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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>
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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>
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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>
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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>
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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>
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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>
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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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Running rtla with exit on threshold, but without saving trace leads to a
segmenetation fault:
$ rtla timerlat hist -T 10
...
Max timerlat IRQ latency from idle: 4.29 us in cpu 0
Segmentation fault
This is caused by null pointer deference in the call of
save_trace_to_file, which attempts to dereference an uninitialized
osnoise_tool variable:
save_trace_to_file(record->trace.inst, params->trace_output);
^ this is uninitialized if params->trace_output is
not set
Fix this by not attempting to dereference "record" if it is NULL and
passing NULL instead. As a safety measure, the first field is also
checked for NULL inside save_trace_to_file.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250313141034.299117-1-tglozar@redhat.com
Fixes: dc4d4e7c72d1 ("rtla: Refactor save_trace_to_file")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The functions osnoise_hist_main(), osnoise_top_main(),
timerlat_hist_main(), and timerlat_top_main() are lengthy and contain
duplicated code.
Refactor by consolidating the duplicate lines into the
save_trace_to_file() function.
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Eder Zulian <ezulian@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250219115138.406075-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Tested-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add a field processed_events to struct trace_instance and increment it
in collect_registered_events, regardless of whether a handler is
registered for the event.
The purpose is to calculate the percentage of events that were missed
due to tracefs buffer overflow.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250123142339.990300-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add function collect_missed_events to trace.c to act as a callback for
tracefs_follow_missed_events, summing the number of total missed events
into a new field missing_events of struct trace_instance.
In case record->missed_events is negative, trace->missed_events is set
to UINT64_MAX to signify an unknown number of events was missed.
The callback is activated on initialization of the trace instance.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250123142339.990300-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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All of the users of trace_is_off() passes in &record->trace as the second
parameter, where record is a pointer to a struct osnoise_tool. This record
could be NULL and there is a hidden dependency that the trace field is the
first field to allow &record->trace to work with a NULL record pointer.
In order to make this code a bit more robust, as record shouldn't be
dereferenced if it is NULL, even if the code does work, create a new
function called osnoise_trace_is_off() that takes the pointer to a
struct osnoise_tool as its second parameter. This way it can properly test
if it is NULL before it dereferences it.
The old function trace_is_off() is removed and the function
osnoise_trace_is_off() is added into osnoise.c which is what the
struct osnoise_tool is associated with.
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Eder Zulian <ezulian@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250115180055.2136815-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Support not only turning trace on for the timerlat tracer, but also
turning it off.
This will be used in subsequent patches to stop the timerlat tracer
without also wiping the trace buffer.
Cc: stable@vger.kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250116144931.649593-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add the option allow the users to set a different buffer size for the
trace. For example, in large systems, the user might be interested on
reducing the trace buffer to avoid large tracing files.
The buffer size is specified in kB, and it is only affecting
the tracing instance.
The function trace_set_buffer_size() appears on libtracefs v1.6,
so increase the minimum required version on Makefile.config.
Link: https://lkml.kernel.org/r/e7c9ca5b3865f28e131a49ec3b984fadf2d056c6.1715860611.git.bristot@kernel.org
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
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Avoid double free by making trace_instance_destroy indempotent. When
trace_instance_init fails, it calls trace_instance_destroy, but its only
caller osnoise_destroy_tool calls it again.
Link: https://lkml.kernel.org/r/mvmilnlkyzx.fsf_-_@suse.de
Fixes: 0605bf009f18 ("rtla: Add osnoise tool")
Signed-off-by: Andreas Schwab <schwab@suse.de>
Acked-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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With the addition of --trigger option, it is also possible to stop
the trace from the -t tracing instance using the traceoff trigger.
Make rtla tools to check if the trace is stopped also in the trace
instance, stopping the execution of the tool.
Link: https://lkml.kernel.org/r/59fc7c6f23dddd5c8b7ef1782cf3da51ea2ce0f5.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The hist: trigger generates a histogram in the file sys/event/hist.
If the hist: trigger is used, automatically save the histogram output of
the event sys:event in the sys_event_hist.txt file.
Link: https://lkml.kernel.org/r/b5c906af31d4e022ffe87fb0848fac5c089087c8.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add a set of helper functions to allow rtla tools to filter events
in the trace instance.
Link: https://lkml.kernel.org/r/12623b1684684549d53b90f4bf66fae44584fd14.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add a set of helper functions to allow rtla tools to trigger event
actions in the trace instance.
Link: https://lkml.kernel.org/r/e0d31abe879a78a5600b64f904d0dfa8f76e4fbb.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Add a set of helper functions to allow the rtla tools to enable
additional tracepoints in the trace instance.
Link: https://lkml.kernel.org/r/932398b36c1bbaa22c7810d7a40ca9b8c5595b94.1646247211.git.bristot@kernel.org
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Clark Williams <williams@redhat.com>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Use capital and change "tracer %s" to "%s tracer".
No functional change.
Link: https://lkml.kernel.org/r/361697d27431afefa64c67c323564205385c418d.1643990447.git.bristot@kernel.org
Fixes: b1696371d865 ("rtla: Helper functions for rtla")
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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This is a set of utils and tracer helper functions. They are used by
rtla mostly to parse config, display data and some trace operations that
are not part of libtracefs (because they are only useful it for this
case).
Link: https://lkml.kernel.org/r/a94c128aba9e6e66d502b7094f2e8c7ac95b12e5.1639158831.git.bristot@kernel.org
Cc: Tao Zhou <tao.zhou@linux.dev>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Tom Zanussi <zanussi@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Cc: John Kacur <jkacur@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: linux-rt-users@vger.kernel.org
Cc: linux-trace-devel@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
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