Merge tag 'trace-rtla-v7.1' of 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
  ...

Author: torvalds

Documentation/tools/rtla/common_appendix.txt

@@ -1,5 +1,26 @@
 .. SPDX-License-Identifier: GPL-2.0
 
+SIGINT BEHAVIOR
+===============
+
+On the first SIGINT, RTLA exits after collecting all outstanding samples up to
+the point of receiving the signal.
+
+When receiving more than one SIGINT, RTLA discards any outstanding samples, and
+exits while displaying only samples that have already been processed.
+
+If SIGINT is received during RTLA cleanup, RTLA exits immediately via
+the default signal handler.
+
+Note: For the purpose of SIGINT behavior, the expiry of duration specified via
+the -d/--duration option is treated as equivalent to receiving a SIGINT. For
+example, a SIGINT received after duration expired but samples have not been
+processed yet will drop any outstanding samples.
+
+Also note that when using the timerlat tool in BPF mode, samples are processed
+in-kernel; RTLA only copies them out to display them to the user. A second
+SIGINT does not affect in-kernel sample aggregation.
+
 EXIT STATUS
 ===========
 

Documentation/tools/rtla/common_timerlat_options.txt

@@ -83,3 +83,15 @@
 
         **Note**: BPF actions require BPF support to be available. If BPF is not available
         or disabled, the tool falls back to tracefs mode and BPF actions are not supported.
+
+**--stack-format** *format*
+
+        Adjust the format of the stack trace printed during auto-analysis.
+
+        The supported values for *format* are:
+
+        * **truncate**    Print the stack trace up to the first unknown address (default).
+        * **skip**        Skip unknown addresses.
+        * **full**        Print the entire stack trace, including unknown addresses.
+
+        For unknown addresses, the raw pointer is printed.

tools/build/Makefile.feature

@@ -115,6 +115,7 @@ FEATURE_TESTS_EXTRA :=                  \
          hello                          \
          libbabeltrace                  \
          libcapstone                    \
+         libcheck                       \
          libbfd-liberty                 \
          libbfd-liberty-z               \
          libopencsd                     \
@@ -176,6 +177,8 @@ ifneq ($(PKG_CONFIG),)
   $(foreach package,$(FEATURE_PKG_CONFIG),$(call feature_pkg_config,$(package)))
 endif
 
+FEATURE_CHECK_LDFLAGS-libcheck = -lcheck
+
 # Set FEATURE_CHECK_(C|LD)FLAGS-all for all FEATURE_TESTS features.
 # If in the future we need per-feature checks/flags for features not
 # mentioned in this list we need to refactor this ;-).

tools/build/feature/Makefile

@@ -50,6 +50,7 @@ FILES=                                          \
          test-timerfd.bin                       \
          test-libbabeltrace.bin                 \
          test-libcapstone.bin			\
+         test-libcheck.bin			\
          test-compile-32.bin                    \
          test-compile-x32.bin                   \
          test-zlib.bin                          \
@@ -307,6 +308,9 @@ $(OUTPUT)test-libbabeltrace.bin:
 $(OUTPUT)test-libcapstone.bin:
 	$(BUILD) # -lcapstone provided by $(FEATURE_CHECK_LDFLAGS-libcapstone)
 
+$(OUTPUT)test-libcheck.bin:
+	$(BUILD) # -lcheck is provided by $(FEATURE_CHECK_LDFLAGS-libcheck)
+
 $(OUTPUT)test-compile-32.bin:
 	$(CC) -m32 -Wall -Werror -o $@ test-compile.c
 

tools/build/feature/test-libcheck.c

@@ -0,0 +1,8 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <check.h>
+
+int main(void)
+{
+	Suite *s = suite_create("test");
+	return s == 0;
+}

tools/tracing/rtla/Build

@@ -1 +1,2 @@
 rtla-y += src/
+unit_tests-y += tests/unit/

tools/tracing/rtla/Makefile

@@ -33,12 +33,14 @@ DOCSRC		:= ../../../Documentation/tools/rtla/
 FEATURE_TESTS	:= libtraceevent
 FEATURE_TESTS	+= libtracefs
 FEATURE_TESTS	+= libcpupower
+FEATURE_TESTS	+= libcheck
 FEATURE_TESTS	+= libbpf
 FEATURE_TESTS	+= clang-bpf-co-re
 FEATURE_TESTS	+= bpftool-skeletons
 FEATURE_DISPLAY	:= libtraceevent
 FEATURE_DISPLAY	+= libtracefs
 FEATURE_DISPLAY	+= libcpupower
+FEATURE_DISPLAY	+= libcheck
 FEATURE_DISPLAY	+= libbpf
 FEATURE_DISPLAY	+= clang-bpf-co-re
 FEATURE_DISPLAY	+= bpftool-skeletons
@@ -47,6 +49,7 @@ all: $(RTLA)
 
 include $(srctree)/tools/build/Makefile.include
 include Makefile.rtla
+include tests/unit/Makefile.unit
 
 # check for dependencies only on required targets
 NON_CONFIG_TARGETS := clean install tarball doc doc_clean doc_install
@@ -109,6 +112,8 @@ clean: doc_clean fixdep-clean
 	$(Q)rm -f rtla rtla-static fixdep FEATURE-DUMP rtla-*
 	$(Q)rm -rf feature
 	$(Q)rm -f src/timerlat.bpf.o src/timerlat.skel.h example/timerlat_bpf_action.o
+	$(Q)rm -f $(UNIT_TESTS)
+
 check: $(RTLA) tests/bpf/bpf_action_map.o
 	RTLA=$(RTLA) BPFTOOL=$(SYSTEM_BPFTOOL) prove -o -f -v tests/
 examples: example/timerlat_bpf_action.o

tools/tracing/rtla/Makefile.config

@@ -61,6 +61,14 @@ else
   $(info Please install libcpupower-dev/kernel-tools-libs-devel)
 endif
 
+$(call feature_check,libcheck)
+ifeq ($(feature-libcheck), 1)
+  $(call detected,CONFIG_LIBCHECK)
+else
+  $(info libcheck is missing, building without unit tests support.)
+  $(info Please install check-devel/check)
+endif
+
 ifndef BUILD_BPF_SKEL
   # BPF skeletons are used to implement improved sample collection, enable
   # them by default.

tools/tracing/rtla/README.txt

@@ -12,6 +12,7 @@ RTLA depends on the following libraries and tools:
  - libtracefs
  - libtraceevent
  - libcpupower (optional, for --deepest-idle-state)
+ - libcheck (optional, for unit tests)
 
 For BPF sample collection support, the following extra dependencies are
 required:

tools/tracing/rtla/src/actions.c

@@ -15,7 +15,7 @@ void
 actions_init(struct actions *self)
 {
 	self->size = action_default_size;
-	self->list = calloc(self->size, sizeof(struct action));
+	self->list = calloc_fatal(self->size, sizeof(struct action));
 	self->len = 0;
 	self->continue_flag = false;
 
@@ -50,8 +50,10 @@ static struct action *
 actions_new(struct actions *self)
 {
 	if (self->len >= self->size) {
-		self->size *= 2;
-		self->list = realloc(self->list, self->size * sizeof(struct action));
+		const size_t new_size = self->size * 2;
+
+		self->list = reallocarray_fatal(self->list, new_size, sizeof(struct action));
+		self->size = new_size;
 	}
 
 	return &self->list[self->len++];
@@ -60,25 +62,20 @@ actions_new(struct actions *self)
 /*
  * actions_add_trace_output - add an action to output trace
  */
-int
+void
 actions_add_trace_output(struct actions *self, const char *trace_output)
 {
 	struct action *action = actions_new(self);
 
 	self->present[ACTION_TRACE_OUTPUT] = true;
 	action->type = ACTION_TRACE_OUTPUT;
-	action->trace_output = calloc(strlen(trace_output) + 1, sizeof(char));
-	if (!action->trace_output)
-		return -1;
-	strcpy(action->trace_output, trace_output);
-
-	return 0;
+	action->trace_output = strdup_fatal(trace_output);
 }
 
 /*
  * actions_add_trace_output - add an action to send signal to a process
  */
-int
+void
 actions_add_signal(struct actions *self, int signal, int pid)
 {
 	struct action *action = actions_new(self);
@@ -87,42 +84,56 @@ actions_add_signal(struct actions *self, int signal, int pid)
 	action->type = ACTION_SIGNAL;
 	action->signal = signal;
 	action->pid = pid;
-
-	return 0;
 }
 
 /*
  * actions_add_shell - add an action to execute a shell command
  */
-int
+void
 actions_add_shell(struct actions *self, const char *command)
 {
 	struct action *action = actions_new(self);
 
 	self->present[ACTION_SHELL] = true;
 	action->type = ACTION_SHELL;
-	action->command = calloc(strlen(command) + 1, sizeof(char));
-	if (!action->command)
-		return -1;
-	strcpy(action->command, command);
-
-	return 0;
+	action->command = strdup_fatal(command);
 }
 
 /*
  * actions_add_continue - add an action to resume measurement
  */
-int
+void
 actions_add_continue(struct actions *self)
 {
 	struct action *action = actions_new(self);
 
 	self->present[ACTION_CONTINUE] = true;
 	action->type = ACTION_CONTINUE;
+}
 
-	return 0;
+static inline const char *__extract_arg(const char *token, const char *opt, size_t opt_len)
+{
+	const size_t tok_len = strlen(token);
+
+	if (tok_len <= opt_len)
+		return NULL;
+
+	if (strncmp(token, opt, opt_len))
+		return NULL;
+
+	return token + opt_len;
 }
 
+/*
+ * extract_arg - extract argument value from option token
+ * @token: option token (e.g., "file=trace.txt")
+ * @opt: option name to match (e.g., "file")
+ *
+ * Returns pointer to argument value after "=" if token matches "opt=",
+ * otherwise returns NULL.
+ */
+#define extract_arg(token, opt) __extract_arg(token, opt "=", STRING_LENGTH(opt "="))
+
 /*
  * actions_parse - add an action based on text specification
  */
@@ -132,6 +143,7 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn)
 	enum action_type type = ACTION_NONE;
 	const char *token;
 	char trigger_c[strlen(trigger) + 1];
+	const char *arg_value;
 
 	/* For ACTION_SIGNAL */
 	int signal = 0, pid = 0;
@@ -164,33 +176,36 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn)
 		if (token == NULL)
 			trace_output = tracefn;
 		else {
-			if (strlen(token) > 5 && strncmp(token, "file=", 5) == 0) {
-				trace_output = token + 5;
-			} else {
+			trace_output = extract_arg(token, "file");
+			if (!trace_output)
 				/* Invalid argument */
 				return -1;
-			}
 
 			token = strtok(NULL, ",");
 			if (token != NULL)
 				/* Only one argument allowed */
 				return -1;
 		}
-		return actions_add_trace_output(self, trace_output);
+		actions_add_trace_output(self, trace_output);
+		break;
 	case ACTION_SIGNAL:
 		/* Takes two arguments, num (signal) and pid */
 		while (token != NULL) {
-			if (strlen(token) > 4 && strncmp(token, "num=", 4) == 0) {
-				if (strtoi(token + 4, &signal))
-					return -1;
-			} else if (strlen(token) > 4 && strncmp(token, "pid=", 4) == 0) {
-				if (strncmp(token + 4, "parent", 7) == 0)
-					pid = -1;
-				else if (strtoi(token + 4, &pid))
+			arg_value = extract_arg(token, "num");
+			if (arg_value) {
+				if (strtoi(arg_value, &signal))
 					return -1;
 			} else {
-				/* Invalid argument */
-				return -1;
+				arg_value = extract_arg(token, "pid");
+				if (arg_value) {
+					if (strncmp_static(arg_value, "parent") == 0)
+						pid = -1;
+					else if (strtoi(arg_value, &pid))
+						return -1;
+				} else {
+					/* Invalid argument */
+					return -1;
+				}
 			}
 
 			token = strtok(NULL, ",");
@@ -200,21 +215,27 @@ actions_parse(struct actions *self, const char *trigger, const char *tracefn)
 			/* Missing argument */
 			return -1;
 
-		return actions_add_signal(self, signal, pid);
+		actions_add_signal(self, signal, pid);
+		break;
 	case ACTION_SHELL:
 		if (token == NULL)
 			return -1;
-		if (strlen(token) > 8 && strncmp(token, "command=", 8) == 0)
-			return actions_add_shell(self, token + 8);
-		return -1;
+		arg_value = extract_arg(token, "command");
+		if (!arg_value)
+			return -1;
+		actions_add_shell(self, arg_value);
+		break;
 	case ACTION_CONTINUE:
 		/* Takes no argument */
 		if (token != NULL)
 			return -1;
-		return actions_add_continue(self);
+		actions_add_continue(self);
+		break;
 	default:
 		return -1;
 	}
+
+	return 0;
 }
 
 /*