Merge tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-tracegrafted

Pull tracing fixes from Steven Rostedt:

 - Fix error output of boot instance creation failure

   Currently if a boot instance creation fails, instead of printing out
   the name of the instance that failed, it prints "(null)". That is
   because it prints "cur_str" that had already been processed by
   strsep(). Print the saved name instead.

   While at it, print the error code of the failure.

 - Fix use-after-free for same named historgrams

   Histograms can be named so that they can be used in multiple events.
   But if the named histogram has a variable attached, the second event
   that uses the named histogram which duplicates it and needs to free
   the original after duplication leaves the old variable in place and
   still visible. If another histogram uses than variable, it will use
   the stale one which will try to reference the freed duplicate
   histogram and crash the kernel.

   Free the duplicate variables along with the duplicated histogram
   data.

 - Check return value of kthread_run() in event self test

   The events self tests uses a kthread for testing but does not check
   if it succeeded in creating a kthread. If the kthread creation were
   to fail, the code will still try to call kthread_stop() on the error
   returned.

 - Fix race between reading trace_pipe and updating subbuffer size

   If a user is reading the trace_pipe file at the same time they update
   the ring buffer sub-buffer size, can cause the trace_pipe read to
   read stale data. Add trace_access_lock() around updating the ring
   buffer sub-buffer size.

 - Fix eventfs_inode on failure path in creation of the events directory

   In the creation of the "events" directory, if after allocating the
   eventfs_inode a failure is detected, it calls cleanup_ei() which
   calls free_ei(). The free_ei() will test if eventfs_inode being freed
   has no children. It is a bug if it does. But on the failure case of
   the creation of the "events" directory, the children lists have not
   yet been initialized and the free will trigger a warning because
   list_empty() on an uninitialized list returns false.

   Move the initialization into init_ei() where it makes more sense and
   makes sure that a created eventfs_inode has its lists initialized
   upon creation.

 - Check return value of kthread_run() in ftrace direct sample code

   The sample code that shows how to use the ftrace direct calls does
   not test the return of kthread_run() to see if it succeeds. Return a
   failure if the kthread_run() doesn't succeed.

 - Clear user events state on fork in case of alloc failure

   On fork, the child gets a pointer to the parent's user events state.
   It makes a copy of it then updates the child's pointer to it. But if
   the allocation fails, the duplication function leaves the child with
   a pointer to its parent's descriptor. When the child cleans up its
   data, it will free the parent's descriptor while the parent is still
   using it.

   In the duplication function, set the child's user_event_mm to NULL
   before testing if the allocation succeeded, and when it exits it will
   not free the parent's descriptor.

 - Fix retry exhaustion in simple ring buffer reader swap

   simple_ring_buffer_swap_reader_page() starts with retry set to 8 and
   post-decrements it only after a failed link replacement. On the final
   attempt, a successful replacement leaves retry at zero, while a
   failed replacement leaves it at -1.

   But the check for success expects the retry value to be non-zero and
   exits with an error on zero. This is the opposite result. Fix it.

 - Fail nicely when the remote swap_reader_page() returns an error

   Currently, if the swap_reader_page() of a remote buffer fails, it
   triggers a WARN_ON_ONCE() and continues normally. Instead, have it
   exit with an error and a pr_warn() print instead of a full WARNING.

* tag 'trace-v7.3-2' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  ring-buffer: Stop remote reader update when page swap fails
  tracing: Fix retry exhaustion in simple ring buffer reader swap
  tracing/user_events: Clear copied tracing state before fork duplication
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-multi-modify
  samples/ftrace: Fix kthread_stop() on ERR_PTR in ftrace-direct-modify
  eventfs: Initialize ei->children and ei->list in init_ei()
  tracing: Fix use-after-free in trace_pipe read on sub-buffer order change
  tracing: Fix crash passing ERR_PTR to kthread_stop()
  tracing: Fix use-after-free with same-name named triggers
  tracing: Fix logged instance name on creation failure

1 files changed, 580 insertions, 0 deletions

diff --git a/tools/perf/perf.c b/tools/perf/perf.c
new file mode 100644
index 000000000..1f51e8de6
--- /dev/null
+++ b/tools/perf/perf.c
@@ -0,0 +1,580 @@
+/*
+ * perf.c
+ *
+ * Performance analysis utility.
+ *
+ * This is the main hub from which the sub-commands (perf stat,
+ * perf top, perf record, perf report, etc.) are started.
+ */
+#include "builtin.h"
+#include "perf.h"
+
+#include "util/build-id.h"
+#include "util/cache.h"
+#include "util/env.h"
+#include <internal/lib.h> // page_size
+#include <subcmd/exec-cmd.h>
+#include "util/config.h"
+#include <subcmd/run-command.h>
+#include "util/parse-events.h"
+#include <subcmd/parse-options.h>
+#include <subcmd/help.h>
+#include "util/debug.h"
+#include "util/event.h"
+#include "util/util.h" // usage()
+#include "ui/ui.h"
+#include "perf-sys.h"
+#include <api/fs/fs.h>
+#include <api/fs/tracing_path.h>
+#include <perf/core.h>
+#include <errno.h>
+#include <pthread.h>
+#include <signal.h>
+#include <stdlib.h>
+#include <time.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/zalloc.h>
+
+static int use_pager = -1;
+static FILE *debug_fp = NULL;
+
+struct cmd_struct {
+	const char *cmd;
+	int (*fn)(int, const char **);
+	int option;
+};
+
+static const struct cmd_struct commands[] = {
+	{ "archive",	NULL,	0 },
+	{ "buildid-cache", cmd_buildid_cache, 0 },
+	{ "buildid-list", cmd_buildid_list, 0 },
+	{ "check",	cmd_check,	0 },
+	{ "config",	cmd_config,	0 },
+	{ "c2c",	cmd_c2c,	0 },
+	{ "diff",	cmd_diff,	0 },
+	{ "evlist",	cmd_evlist,	0 },
+	{ "help",	cmd_help,	0 },
+	{ "iostat",	NULL,	0 },
+	{ "kallsyms",	cmd_kallsyms,	0 },
+	{ "list",	cmd_list,	0 },
+	{ "record",	cmd_record,	0 },
+	{ "report",	cmd_report,	0 },
+	{ "bench",	cmd_bench,	0 },
+	{ "stat",	cmd_stat,	0 },
+#ifdef HAVE_LIBTRACEEVENT
+	{ "timechart",	cmd_timechart,	0 },
+#endif
+	{ "top",	cmd_top,	0 },
+	{ "annotate",	cmd_annotate,	0 },
+	{ "version",	cmd_version,	0 },
+	{ "script",	cmd_script,	0 },
+#ifdef HAVE_LIBTRACEEVENT
+	{ "sched",	cmd_sched,	0 },
+#endif
+#ifdef HAVE_LIBELF_SUPPORT
+	{ "probe",	cmd_probe,	0 },
+#endif
+#ifdef HAVE_LIBTRACEEVENT
+	{ "kmem",	cmd_kmem,	0 },
+	{ "lock",	cmd_lock,	0 },
+#endif
+	{ "kvm",	cmd_kvm,	0 },
+	{ "test",	cmd_test,	0 },
+#if defined(HAVE_LIBTRACEEVENT)
+	{ "trace",	cmd_trace,	0 },
+#endif
+	{ "inject",	cmd_inject,	0 },
+	{ "mem",	cmd_mem,	0 },
+	{ "data",	cmd_data,	0 },
+	{ "ftrace",	cmd_ftrace,	0 },
+	{ "daemon",	cmd_daemon,	0 },
+#ifdef HAVE_LIBTRACEEVENT
+	{ "kwork",	cmd_kwork,	0 },
+#endif
+};
+
+struct pager_config {
+	const char *cmd;
+	int val;
+};
+
+static bool same_cmd_with_prefix(const char *var, struct pager_config *c,
+				  const char *header)
+{
+	return (strstarts(var, header) && !strcmp(var + strlen(header), c->cmd));
+}
+
+static int pager_command_config(const char *var, const char *value, void *data)
+{
+	struct pager_config *c = data;
+	if (same_cmd_with_prefix(var, c, "pager."))
+		c->val = perf_config_bool(var, value);
+	return 0;
+}
+
+/* returns 0 for "no pager", 1 for "use pager", and -1 for "not specified" */
+static int check_pager_config(const char *cmd)
+{
+	int err;
+	struct pager_config c;
+	c.cmd = cmd;
+	c.val = -1;
+	err = perf_config(pager_command_config, &c);
+	return err ?: c.val;
+}
+
+static int browser_command_config(const char *var, const char *value, void *data)
+{
+	struct pager_config *c = data;
+	if (same_cmd_with_prefix(var, c, "tui."))
+		c->val = perf_config_bool(var, value);
+	if (same_cmd_with_prefix(var, c, "gtk."))
+		c->val = perf_config_bool(var, value) ? 2 : 0;
+	return 0;
+}
+
+/*
+ * returns 0 for "no tui", 1 for "use tui", 2 for "use gtk",
+ * and -1 for "not specified"
+ */
+static int check_browser_config(const char *cmd)
+{
+	int err;
+	struct pager_config c;
+	c.cmd = cmd;
+	c.val = -1;
+	err = perf_config(browser_command_config, &c);
+	return err ?: c.val;
+}
+
+static void commit_pager_choice(void)
+{
+	switch (use_pager) {
+	case 0:
+		setenv(PERF_PAGER_ENVIRONMENT, "cat", 1);
+		break;
+	case 1:
+		/* setup_pager(); */
+		break;
+	default:
+		break;
+	}
+}
+
+static int set_debug_file(const char *path)
+{
+	debug_fp = fopen(path, "w");
+	if (!debug_fp) {
+		fprintf(stderr, "Open debug file '%s' failed: %m\n",
+			path);
+		return -1;
+	}
+
+	debug_set_file(debug_fp);
+	return 0;
+}
+
+static const struct option options[] = {
+	OPT_ARGUMENT("help", "help"),
+	OPT_ARGUMENT("version", "version"),
+	OPT_ARGUMENT("exec-path", "exec-path"),
+	OPT_ARGUMENT("html-path", "html-path"),
+	OPT_ARGUMENT("paginate", "paginate"),
+	OPT_ARGUMENT("no-pager", "no-pager"),
+	OPT_ARGUMENT("debugfs-dir", "debugfs-dir"),
+	OPT_ARGUMENT("buildid-dir", "buildid-dir"),
+	OPT_ARGUMENT("list-cmds", "list-cmds"),
+	OPT_ARGUMENT("list-opts", "list-opts"),
+	OPT_ARGUMENT("debug", "debug"),
+	OPT_ARGUMENT("debug-file", "debug-file"),
+	OPT_END()
+};
+
+static int handle_options(const char ***argv, int *argc, int *envchanged)
+{
+	int handled = 0;
+
+	while (*argc > 0) {
+		const char *cmd = (*argv)[0];
+		if (cmd[0] != '-')
+			break;
+
+		/*
+		 * For legacy reasons, the "version" and "help"
+		 * commands can be written with "--" prepended
+		 * to make them look like flags.
+		 */
+		if (!strcmp(cmd, "--help") || !strcmp(cmd, "--version"))
+			break;
+
+		/*
+		 * Shortcut for '-h' and '-v' options to invoke help
+		 * and version command.
+		 */
+		if (!strcmp(cmd, "-h")) {
+			(*argv)[0] = "--help";
+			break;
+		}
+
+		if (!strcmp(cmd, "-v")) {
+			(*argv)[0] = "--version";
+			break;
+		}
+
+		if (!strcmp(cmd, "-vv")) {
+			(*argv)[0] = "version";
+			verbose = 1;
+			break;
+		}
+
+		/*
+		 * Check remaining flags.
+		 */
+		if (strstarts(cmd, CMD_EXEC_PATH)) {
+			cmd += strlen(CMD_EXEC_PATH);
+			if (*cmd == '=')
+				set_argv_exec_path(cmd + 1);
+			else {
+				puts(get_argv_exec_path());
+				exit(0);
+			}
+		} else if (!strcmp(cmd, "--html-path")) {
+			puts(system_path(PERF_HTML_PATH));
+			exit(0);
+		} else if (!strcmp(cmd, "-p") || !strcmp(cmd, "--paginate")) {
+			use_pager = 1;
+		} else if (!strcmp(cmd, "--no-pager")) {
+			use_pager = 0;
+			if (envchanged)
+				*envchanged = 1;
+		} else if (!strcmp(cmd, "--debugfs-dir")) {
+			if (*argc < 2) {
+				fprintf(stderr, "No directory given for --debugfs-dir.\n");
+				usage(perf_usage_string);
+			}
+			tracing_path_set((*argv)[1]);
+			if (envchanged)
+				*envchanged = 1;
+			(*argv)++;
+			(*argc)--;
+		} else if (!strcmp(cmd, "--buildid-dir")) {
+			if (*argc < 2) {
+				fprintf(stderr, "No directory given for --buildid-dir.\n");
+				usage(perf_usage_string);
+			}
+			set_buildid_dir((*argv)[1]);
+			if (envchanged)
+				*envchanged = 1;
+			(*argv)++;
+			(*argc)--;
+		} else if (strstarts(cmd, CMD_DEBUGFS_DIR)) {
+			tracing_path_set(cmd + strlen(CMD_DEBUGFS_DIR));
+			fprintf(stderr, "dir: %s\n", tracing_path_mount());
+			if (envchanged)
+				*envchanged = 1;
+		} else if (!strcmp(cmd, "--list-cmds")) {
+			unsigned int i;
+
+			for (i = 0; i < ARRAY_SIZE(commands); i++) {
+				const struct cmd_struct *p = commands + i;
+				printf("%s ", p->cmd);
+			}
+			putchar('\n');
+			exit(0);
+		} else if (!strcmp(cmd, "--list-opts")) {
+			unsigned int i;
+
+			for (i = 0; i < ARRAY_SIZE(options)-1; i++) {
+				const struct option *p = options + i;
+				printf("--%s ", p->long_name);
+			}
+			putchar('\n');
+			exit(0);
+		} else if (!strcmp(cmd, "--debug")) {
+			if (*argc < 2) {
+				fprintf(stderr, "No variable specified for --debug.\n");
+				usage(perf_usage_string);
+			}
+			if (perf_debug_option((*argv)[1]))
+				usage(perf_usage_string);
+
+			(*argv)++;
+			(*argc)--;
+		} else if (!strcmp(cmd, "--debug-file")) {
+			if (*argc < 2) {
+				fprintf(stderr, "No path given for --debug-file.\n");
+				usage(perf_usage_string);
+			}
+
+			if (set_debug_file((*argv)[1]))
+				usage(perf_usage_string);
+
+			(*argv)++;
+			(*argc)--;
+
+		} else {
+			fprintf(stderr, "Unknown option: %s\n", cmd);
+			usage(perf_usage_string);
+		}
+
+		(*argv)++;
+		(*argc)--;
+		handled++;
+	}
+	return handled;
+}
+
+#define RUN_SETUP	(1<<0)
+#define USE_PAGER	(1<<1)
+
+static int run_builtin(const struct cmd_struct *p, int argc, const char **argv)
+{
+	int status;
+	struct stat st;
+
+	if (use_browser == -1)
+		use_browser = check_browser_config(p->cmd);
+
+	if (use_pager == -1 && p->option & RUN_SETUP)
+		use_pager = check_pager_config(p->cmd);
+	if (use_pager == -1 && p->option & USE_PAGER)
+		use_pager = 1;
+	commit_pager_choice();
+
+	status = p->fn(argc, argv);
+	perf_config__exit();
+	exit_browser(status);
+
+	if (status)
+		return status & 0xff;
+
+	/* Somebody closed stdout? */
+	if (fstat(fileno(stdout), &st))
+		return 0;
+	/* Ignore write errors for pipes and sockets.. */
+	if (S_ISFIFO(st.st_mode) || S_ISSOCK(st.st_mode))
+		return 0;
+
+	status = 1;
+	/* Check for ENOSPC and EIO errors.. */
+	if (fflush(stdout)) {
+		fprintf(stderr, "write failure on standard output: %m\n");
+		goto out;
+	}
+	if (ferror(stdout)) {
+		fprintf(stderr, "unknown write failure on standard output\n");
+		goto out;
+	}
+	if (fclose(stdout)) {
+		fprintf(stderr, "close failed on standard output: %m\n");
+		goto out;
+	}
+	status = 0;
+out:
+	return status;
+}
+
+static void handle_internal_command(int argc, const char **argv)
+{
+	const char *cmd = argv[0];
+	unsigned int i;
+
+	/* Turn "perf cmd --help" into "perf help cmd" */
+	if (argc > 1 && !strcmp(argv[1], "--help")) {
+		argv[1] = argv[0];
+		argv[0] = cmd = "help";
+	}
+
+	for (i = 0; i < ARRAY_SIZE(commands); i++) {
+		const struct cmd_struct *p = commands+i;
+		if (p->fn == NULL)
+			continue;
+		if (strcmp(p->cmd, cmd))
+			continue;
+		exit(run_builtin(p, argc, argv));
+	}
+}
+
+static void execv_dashed_external(const char **argv)
+{
+	char *cmd;
+	const char *tmp;
+	int status;
+
+	if (asprintf(&cmd, "perf-%s", argv[0]) < 0)
+		goto do_die;
+
+	/*
+	 * argv[0] must be the perf command, but the argv array
+	 * belongs to the caller, and may be reused in
+	 * subsequent loop iterations. Save argv[0] and
+	 * restore it on error.
+	 */
+	tmp = argv[0];
+	argv[0] = cmd;
+
+	/*
+	 * if we fail because the command is not found, it is
+	 * OK to return. Otherwise, we just pass along the status code.
+	 */
+	status = run_command_v_opt(argv, 0);
+	if (status != -ERR_RUN_COMMAND_EXEC) {
+		if (IS_RUN_COMMAND_ERR(status)) {
+do_die:
+			pr_err("FATAL: unable to run '%s'", argv[0]);
+			status = -128;
+		}
+		exit(-status);
+	}
+	errno = ENOENT; /* as if we called execvp */
+
+	argv[0] = tmp;
+	zfree(&cmd);
+}
+
+static int run_argv(int *argcp, const char ***argv)
+{
+	/* See if it's an internal command */
+	handle_internal_command(*argcp, *argv);
+
+	/* .. then try the external ones */
+	execv_dashed_external(*argv);
+	return 0;
+}
+
+static int libperf_print(enum libperf_print_level level,
+			 const char *fmt, va_list ap)
+{
+	return veprintf(level, verbose, fmt, ap);
+}
+
+int main(int argc, const char **argv)
+{
+	int err, done_help = 0;
+	const char *cmd;
+
+	perf_debug_setup();
+
+	/* libsubcmd init */
+	exec_cmd_init("perf", PREFIX, PERF_EXEC_PATH, EXEC_PATH_ENVIRONMENT);
+	pager_init(PERF_PAGER_ENVIRONMENT);
+
+	libperf_init(libperf_print);
+
+	cmd = extract_argv0_path(argv[0]);
+	if (!cmd)
+		cmd = "perf-help";
+
+	srandom(time(NULL));
+
+	/* Setting $PERF_CONFIG makes perf read _only_ the given config file. */
+	config_exclusive_filename = getenv("PERF_CONFIG");
+
+	err = perf_config(perf_default_config, NULL);
+	if (err)
+		return err;
+	set_buildid_dir(NULL);
+
+	/*
+	 * "perf-xxxx" is the same as "perf xxxx", but we obviously:
+	 *
+	 *  - cannot take flags in between the "perf" and the "xxxx".
+	 *  - cannot execute it externally (since it would just do
+	 *    the same thing over again)
+	 *
+	 * So we just directly call the internal command handler. If that one
+	 * fails to handle this, then maybe we just run a renamed perf binary
+	 * that contains a dash in its name. To handle this scenario, we just
+	 * fall through and ignore the "xxxx" part of the command string.
+	 */
+	if (strstarts(cmd, "perf-")) {
+		cmd += 5;
+		argv[0] = cmd;
+		handle_internal_command(argc, argv);
+		/*
+		 * If the command is handled, the above function does not
+		 * return undo changes and fall through in such a case.
+		 */
+		cmd -= 5;
+		argv[0] = cmd;
+	}
+	if (strstarts(cmd, "trace")) {
+#ifndef HAVE_LIBTRACEEVENT
+		fprintf(stderr,
+			"trace command not available: missing libtraceevent devel package at build time.\n");
+		goto out;
+#else
+		setup_path();
+		argv[0] = "trace";
+		return cmd_trace(argc, argv);
+#endif
+	}
+	/* Look for flags.. */
+	argv++;
+	argc--;
+	handle_options(&argv, &argc, NULL);
+	commit_pager_choice();
+
+	if (argc > 0) {
+		if (strstarts(argv[0], "--"))
+			argv[0] += 2;
+	} else {
+		/* The user didn't specify a command; give them help */
+		printf("\n usage: %s\n\n", perf_usage_string);
+		list_common_cmds_help();
+		printf("\n %s\n\n", perf_more_info_string);
+		goto out;
+	}
+	cmd = argv[0];
+
+	/*
+	 * We use PATH to find perf commands, but we prepend some higher
+	 * precedence paths: the "--exec-path" option, the PERF_EXEC_PATH
+	 * environment, and the $(perfexecdir) from the Makefile at build
+	 * time.
+	 */
+	setup_path();
+	/*
+	 * Block SIGWINCH notifications so that the thread that wants it can
+	 * unblock and get syscalls like select interrupted instead of waiting
+	 * forever while the signal goes to some other non interested thread.
+	 */
+	pthread__block_sigwinch();
+
+	while (1) {
+		run_argv(&argc, &argv);
+
+		if (errno != ENOENT)
+			break;
+
+		if (!done_help) {
+			struct cmdnames main_cmds = {};
+
+			for (unsigned int i = 0; i < ARRAY_SIZE(commands); i++) {
+				add_cmdname(&main_cmds,
+					    commands[i].cmd,
+					    strlen(commands[i].cmd));
+			}
+			cmd = argv[0] = help_unknown_cmd(cmd, &main_cmds);
+			clean_cmdnames(&main_cmds);
+			done_help = 1;
+			if (!cmd)
+				break;
+		} else
+			break;
+	}
+
+	if (cmd) {
+		fprintf(stderr, "Failed to run command '%s': %m\n",
+			cmd);
+	}
+out:
+	if (debug_fp)
+		fclose(debug_fp);
+
+	return 1;
+}