Merge tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace

Pull tracing updates from Steven Rostedt:

 - Added new "bootconfig".

   This looks for a file appended to initrd to add boot config options,
   and has been discussed thoroughly at Linux Plumbers.

   Very useful for adding kprobes at bootup.

   Only enabled if "bootconfig" is on the real kernel command line.

 - Created dynamic event creation.

   Merges common code between creating synthetic events and kprobe
   events.

 - Rename perf "ring_buffer" structure to "perf_buffer"

 - Rename ftrace "ring_buffer" structure to "trace_buffer"

   Had to rename existing "trace_buffer" to "array_buffer"

 - Allow trace_printk() to work withing (some) tracing code.

 - Sort of tracing configs to be a little better organized

 - Fixed bug where ftrace_graph hash was not being protected properly

 - Various other small fixes and clean ups

* tag 'trace-v5.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-trace: (88 commits)
  bootconfig: Show the number of nodes on boot message
  tools/bootconfig: Show the number of bootconfig nodes
  bootconfig: Add more parse error messages
  bootconfig: Use bootconfig instead of boot config
  ftrace: Protect ftrace_graph_hash with ftrace_sync
  ftrace: Add comment to why rcu_dereference_sched() is open coded
  tracing: Annotate ftrace_graph_notrace_hash pointer with __rcu
  tracing: Annotate ftrace_graph_hash pointer with __rcu
  bootconfig: Only load bootconfig if "bootconfig" is on the kernel cmdline
  tracing: Use seq_buf for building dynevent_cmd string
  tracing: Remove useless code in dynevent_arg_pair_add()
  tracing: Remove check_arg() callbacks from dynevent args
  tracing: Consolidate some synth_event_trace code
  tracing: Fix now invalid var_ref_vals assumption in trace action
  tracing: Change trace_boot to use synth_event interface
  tracing: Move tracing selftests to bottom of menu
  tracing: Move mmio tracer config up with the other tracers
  tracing: Move tracing test module configs together
  tracing: Move all function tracing configs together
  tracing: Documentation for in-kernel synthetic event API
  ...

1 files changed, 225 insertions, 0 deletions

diff --git a/kernel/trace/kprobe_event_gen_test.c b/kernel/trace/kprobe_event_gen_test.c
new file mode 100644
index 000000000000..18b0f1cbb947
--- /dev/null
+++ b/kernel/trace/kprobe_event_gen_test.c
@@ -0,0 +1,225 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Test module for in-kernel kprobe event creation and generation.
+ *
+ * Copyright (C) 2019 Tom Zanussi <zanussi@kernel.org>
+ */
+
+#include <linux/module.h>
+#include <linux/trace_events.h>
+
+/*
+ * This module is a simple test of basic functionality for in-kernel
+ * kprobe/kretprobe event creation.  The first test uses
+ * kprobe_event_gen_cmd_start(), kprobe_event_add_fields() and
+ * kprobe_event_gen_cmd_end() to create a kprobe event, which is then
+ * enabled in order to generate trace output.  The second creates a
+ * kretprobe event using kretprobe_event_gen_cmd_start() and
+ * kretprobe_event_gen_cmd_end(), and is also then enabled.
+ *
+ * To test, select CONFIG_KPROBE_EVENT_GEN_TEST and build the module.
+ * Then:
+ *
+ * # insmod kernel/trace/kprobe_event_gen_test.ko
+ * # cat /sys/kernel/debug/tracing/trace
+ *
+ * You should see many instances of the "gen_kprobe_test" and
+ * "gen_kretprobe_test" events in the trace buffer.
+ *
+ * To remove the events, remove the module:
+ *
+ * # rmmod kprobe_event_gen_test
+ *
+ */
+
+static struct trace_event_file *gen_kprobe_test;
+static struct trace_event_file *gen_kretprobe_test;
+
+/*
+ * Test to make sure we can create a kprobe event, then add more
+ * fields.
+ */
+static int __init test_gen_kprobe_cmd(void)
+{
+	struct dynevent_cmd cmd;
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Define the gen_kprobe_test event with the first 2 kprobe
+	 * fields.
+	 */
+	ret = kprobe_event_gen_cmd_start(&cmd, "gen_kprobe_test",
+					 "do_sys_open",
+					 "dfd=%ax", "filename=%dx");
+	if (ret)
+		goto free;
+
+	/* Use kprobe_event_add_fields to add the rest of the fields */
+
+	ret = kprobe_event_add_fields(&cmd, "flags=%cx", "mode=+4($stack)");
+	if (ret)
+		goto free;
+
+	/*
+	 * This actually creates the event.
+	 */
+	ret = kprobe_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto free;
+
+	/*
+	 * Now get the gen_kprobe_test event file.  We need to prevent
+	 * the instance and event from disappearing from underneath
+	 * us, which trace_get_event_file() does (though in this case
+	 * we're using the top-level instance which never goes away).
+	 */
+	gen_kprobe_test = trace_get_event_file(NULL, "kprobes",
+					       "gen_kprobe_test");
+	if (IS_ERR(gen_kprobe_test)) {
+		ret = PTR_ERR(gen_kprobe_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(gen_kprobe_test->tr,
+					"kprobes", "gen_kprobe_test", true);
+	if (ret) {
+		trace_put_event_file(gen_kprobe_test);
+		goto delete;
+	}
+ out:
+	return ret;
+ delete:
+	/* We got an error after creating the event, delete it */
+	ret = kprobe_event_delete("gen_kprobe_test");
+ free:
+	kfree(buf);
+
+	goto out;
+}
+
+/*
+ * Test to make sure we can create a kretprobe event.
+ */
+static int __init test_gen_kretprobe_cmd(void)
+{
+	struct dynevent_cmd cmd;
+	char *buf;
+	int ret;
+
+	/* Create a buffer to hold the generated command */
+	buf = kzalloc(MAX_DYNEVENT_CMD_LEN, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	/* Before generating the command, initialize the cmd object */
+	kprobe_event_cmd_init(&cmd, buf, MAX_DYNEVENT_CMD_LEN);
+
+	/*
+	 * Define the kretprobe event.
+	 */
+	ret = kretprobe_event_gen_cmd_start(&cmd, "gen_kretprobe_test",
+					    "do_sys_open",
+					    "$retval");
+	if (ret)
+		goto free;
+
+	/*
+	 * This actually creates the event.
+	 */
+	ret = kretprobe_event_gen_cmd_end(&cmd);
+	if (ret)
+		goto free;
+
+	/*
+	 * Now get the gen_kretprobe_test event file.  We need to
+	 * prevent the instance and event from disappearing from
+	 * underneath us, which trace_get_event_file() does (though in
+	 * this case we're using the top-level instance which never
+	 * goes away).
+	 */
+	gen_kretprobe_test = trace_get_event_file(NULL, "kprobes",
+						  "gen_kretprobe_test");
+	if (IS_ERR(gen_kretprobe_test)) {
+		ret = PTR_ERR(gen_kretprobe_test);
+		goto delete;
+	}
+
+	/* Enable the event or you won't see anything */
+	ret = trace_array_set_clr_event(gen_kretprobe_test->tr,
+					"kprobes", "gen_kretprobe_test", true);
+	if (ret) {
+		trace_put_event_file(gen_kretprobe_test);
+		goto delete;
+	}
+ out:
+	return ret;
+ delete:
+	/* We got an error after creating the event, delete it */
+	ret = kprobe_event_delete("gen_kretprobe_test");
+ free:
+	kfree(buf);
+
+	goto out;
+}
+
+static int __init kprobe_event_gen_test_init(void)
+{
+	int ret;
+
+	ret = test_gen_kprobe_cmd();
+	if (ret)
+		return ret;
+
+	ret = test_gen_kretprobe_cmd();
+	if (ret) {
+		WARN_ON(trace_array_set_clr_event(gen_kretprobe_test->tr,
+						  "kprobes",
+						  "gen_kretprobe_test", false));
+		trace_put_event_file(gen_kretprobe_test);
+		WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
+	}
+
+	return ret;
+}
+
+static void __exit kprobe_event_gen_test_exit(void)
+{
+	/* Disable the event or you can't remove it */
+	WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+					  "kprobes",
+					  "gen_kprobe_test", false));
+
+	/* Now give the file and instance back */
+	trace_put_event_file(gen_kprobe_test);
+
+	/* Now unregister and free the event */
+	WARN_ON(kprobe_event_delete("gen_kprobe_test"));
+
+	/* Disable the event or you can't remove it */
+	WARN_ON(trace_array_set_clr_event(gen_kprobe_test->tr,
+					  "kprobes",
+					  "gen_kretprobe_test", false));
+
+	/* Now give the file and instance back */
+	trace_put_event_file(gen_kretprobe_test);
+
+	/* Now unregister and free the event */
+	WARN_ON(kprobe_event_delete("gen_kretprobe_test"));
+}
+
+module_init(kprobe_event_gen_test_init)
+module_exit(kprobe_event_gen_test_exit)
+
+MODULE_AUTHOR("Tom Zanussi");
+MODULE_DESCRIPTION("kprobe event generation test");
+MODULE_LICENSE("GPL v2");