Merge tag 'perf-core-for-mingo-4.11-20170126' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux into perf/core

Pull the latest perf/core updates from Arnaldo Carvalho de Melo:

New features:

 - Introduce 'perf ftrace' a perf front end to the kernel's ftrace
   function and function_graph tracer, defaulting to the "function_graph"
   tracer, more work will be done in reviving this effort, forward porting
   it from its initial patch submission (Namhyung Kim)

 - Add 'e' and 'c' hotkeys to expand/collapse call chains for a single
   hist entry in the 'perf report' and 'perf top' TUI (Jiri Olsa)

Fixes:

 - Fix wrong register name for arm64, used in 'perf probe' (He Kuang)

 - Fix map offsets in relocation in libbpf (Joe Stringer)

 - Fix looking up dwarf unwind stack info (Matija Glavinic Pecotic)

Infrastructure changes:

 - libbpf prog functions sync with what is exported via uapi (Joe Stringer)

Trivial changes:

 - Remove unnecessary checks and assignments in 'perf probe's
   try_to_find_absolute_address() (Markus Elfring)

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>

tools/lib/bpf/libbpf.c

@@ -28,6 +28,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <asm/unistd.h>
+#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/bpf.h>
 #include <linux/list.h>
@@ -779,7 +780,7 @@ static int
 bpf_program__collect_reloc(struct bpf_program *prog,
 			   size_t nr_maps, GElf_Shdr *shdr,
 			   Elf_Data *data, Elf_Data *symbols,
-			   int maps_shndx)
+			   int maps_shndx, struct bpf_map *maps)
 {
 	int i, nrels;
 
@@ -829,7 +830,15 @@ bpf_program__collect_reloc(struct bpf_program *prog,
 			return -LIBBPF_ERRNO__RELOC;
 		}
 
-		map_idx = sym.st_value / sizeof(struct bpf_map_def);
+		/* TODO: 'maps' is sorted. We can use bsearch to make it faster. */
+		for (map_idx = 0; map_idx < nr_maps; map_idx++) {
+			if (maps[map_idx].offset == sym.st_value) {
+				pr_debug("relocation: find map %zd (%s) for insn %u\n",
+					 map_idx, maps[map_idx].name, insn_idx);
+				break;
+			}
+		}
+
 		if (map_idx >= nr_maps) {
 			pr_warning("bpf relocation: map_idx %d large than %d\n",
 				   (int)map_idx, (int)nr_maps - 1);
@@ -953,7 +962,8 @@ static int bpf_object__collect_reloc(struct bpf_object *obj)
 		err = bpf_program__collect_reloc(prog, nr_maps,
 						 shdr, data,
 						 obj->efile.symbols,
-						 obj->efile.maps_shndx);
+						 obj->efile.maps_shndx,
+						 obj->maps);
 		if (err)
 			return err;
 	}
@@ -1419,37 +1429,33 @@ static void bpf_program__set_type(struct bpf_program *prog,
 	prog->type = type;
 }
 
-int bpf_program__set_tracepoint(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-	return 0;
-}
-
-int bpf_program__set_kprobe(struct bpf_program *prog)
-{
-	if (!prog)
-		return -EINVAL;
-	bpf_program__set_type(prog, BPF_PROG_TYPE_KPROBE);
-	return 0;
-}
-
 static bool bpf_program__is_type(struct bpf_program *prog,
 				 enum bpf_prog_type type)
 {
 	return prog ? (prog->type == type) : false;
 }
 
-bool bpf_program__is_tracepoint(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_TRACEPOINT);
-}
-
-bool bpf_program__is_kprobe(struct bpf_program *prog)
-{
-	return bpf_program__is_type(prog, BPF_PROG_TYPE_KPROBE);
-}
+#define BPF_PROG_TYPE_FNS(NAME, TYPE)			\
+int bpf_program__set_##NAME(struct bpf_program *prog)	\
+{							\
+	if (!prog)					\
+		return -EINVAL;				\
+	bpf_program__set_type(prog, TYPE);		\
+	return 0;					\
+}							\
+							\
+bool bpf_program__is_##NAME(struct bpf_program *prog)	\
+{							\
+	return bpf_program__is_type(prog, TYPE);	\
+}							\
+
+BPF_PROG_TYPE_FNS(socket_filter, BPF_PROG_TYPE_SOCKET_FILTER);
+BPF_PROG_TYPE_FNS(kprobe, BPF_PROG_TYPE_KPROBE);
+BPF_PROG_TYPE_FNS(sched_cls, BPF_PROG_TYPE_SCHED_CLS);
+BPF_PROG_TYPE_FNS(sched_act, BPF_PROG_TYPE_SCHED_ACT);
+BPF_PROG_TYPE_FNS(tracepoint, BPF_PROG_TYPE_TRACEPOINT);
+BPF_PROG_TYPE_FNS(xdp, BPF_PROG_TYPE_XDP);
+BPF_PROG_TYPE_FNS(perf_event, BPF_PROG_TYPE_PERF_EVENT);
 
 int bpf_map__fd(struct bpf_map *map)
 {
@@ -1537,3 +1543,10 @@ bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset)
 	}
 	return ERR_PTR(-ENOENT);
 }
+
+long libbpf_get_error(const void *ptr)
+{
+	if (IS_ERR(ptr))
+		return PTR_ERR(ptr);
+	return 0;
+}

tools/lib/bpf/libbpf.h

@@ -22,8 +22,8 @@
 #define __BPF_LIBBPF_H
 
 #include <stdio.h>
+#include <stdint.h>
 #include <stdbool.h>
-#include <linux/err.h>
 #include <sys/types.h>  // for size_t
 
 enum libbpf_errno {
@@ -174,11 +174,21 @@ int bpf_program__nth_fd(struct bpf_program *prog, int n);
 /*
  * Adjust type of bpf program. Default is kprobe.
  */
+int bpf_program__set_socket_filter(struct bpf_program *prog);
 int bpf_program__set_tracepoint(struct bpf_program *prog);
 int bpf_program__set_kprobe(struct bpf_program *prog);
+int bpf_program__set_sched_cls(struct bpf_program *prog);
+int bpf_program__set_sched_act(struct bpf_program *prog);
+int bpf_program__set_xdp(struct bpf_program *prog);
+int bpf_program__set_perf_event(struct bpf_program *prog);
 
+bool bpf_program__is_socket_filter(struct bpf_program *prog);
 bool bpf_program__is_tracepoint(struct bpf_program *prog);
 bool bpf_program__is_kprobe(struct bpf_program *prog);
+bool bpf_program__is_sched_cls(struct bpf_program *prog);
+bool bpf_program__is_sched_act(struct bpf_program *prog);
+bool bpf_program__is_xdp(struct bpf_program *prog);
+bool bpf_program__is_perf_event(struct bpf_program *prog);
 
 /*
  * We don't need __attribute__((packed)) now since it is
@@ -224,4 +234,6 @@ int bpf_map__set_priv(struct bpf_map *map, void *priv,
 		      bpf_map_clear_priv_t clear_priv);
 void *bpf_map__priv(struct bpf_map *map);
 
+long libbpf_get_error(const void *ptr);
+
 #endif

tools/perf/Build

@@ -3,6 +3,7 @@ perf-y += builtin-annotate.o
 perf-y += builtin-config.o
 perf-y += builtin-diff.o
 perf-y += builtin-evlist.o
+perf-y += builtin-ftrace.o
 perf-y += builtin-help.o
 perf-y += builtin-sched.o
 perf-y += builtin-buildid-list.o

tools/perf/Documentation/perf-c2c.txt

@@ -248,7 +248,7 @@ output fields set for caheline offsets output:
              Code address, Code symbol, Shared Object, Source line
   dso   - coalesced by shared object
 
-By default the coalescing is setup with 'pid,tid,iaddr'.
+By default the coalescing is setup with 'pid,iaddr'.
 
 STDIO OUTPUT
 ------------

tools/perf/Documentation/perf-ftrace.txt

@@ -0,0 +1,36 @@
+perf-ftrace(1)
+=============
+
+NAME
+----
+perf-ftrace - simple wrapper for kernel's ftrace functionality
+
+
+SYNOPSIS
+--------
+[verse]
+'perf ftrace' <command>
+
+DESCRIPTION
+-----------
+The 'perf ftrace' command is a simple wrapper of kernel's ftrace
+functionality.  It only supports single thread tracing currently and
+just reads trace_pipe in text and then write it to stdout.
+
+The following options apply to perf ftrace.
+
+OPTIONS
+-------
+
+-t::
+--tracer=::
+	Tracer to use: function_graph or function.
+
+-v::
+--verbose=::
+        Verbosity level.
+
+
+SEE ALSO
+--------
+linkperf:perf-record[1], linkperf:perf-trace[1]

tools/perf/arch/arm64/include/dwarf-regs-table.h

@@ -2,12 +2,12 @@
 /* This is included in perf/util/dwarf-regs.c */
 
 static const char * const aarch64_regstr_tbl[] = {
-	"%r0", "%r1", "%r2", "%r3", "%r4",
-	"%r5", "%r6", "%r7", "%r8", "%r9",
-	"%r10", "%r11", "%r12", "%r13", "%r14",
-	"%r15", "%r16", "%r17", "%r18", "%r19",
-	"%r20", "%r21", "%r22", "%r23", "%r24",
-	"%r25", "%r26", "%r27", "%r28", "%r29",
+	"%x0", "%x1", "%x2", "%x3", "%x4",
+	"%x5", "%x6", "%x7", "%x8", "%x9",
+	"%x10", "%x11", "%x12", "%x13", "%x14",
+	"%x15", "%x16", "%x17", "%x18", "%x19",
+	"%x20", "%x21", "%x22", "%x23", "%x24",
+	"%x25", "%x26", "%x27", "%x28", "%x29",
 	"%lr", "%sp",
 };
 #endif

tools/perf/builtin-c2c.c

@@ -58,7 +58,7 @@ struct c2c_hist_entry {
 	struct hist_entry	he;
 };
 
-static char const *coalesce_default = "pid,tid,iaddr";
+static char const *coalesce_default = "pid,iaddr";
 
 struct perf_c2c {
 	struct perf_tool	tool;
@@ -2476,6 +2476,7 @@ static int build_cl_output(char *cl_sort, bool no_source)
 		"mean_rmt,"
 		"mean_lcl,"
 		"mean_load,"
+		"tot_recs,"
 		"cpucnt,",
 		add_sym ? "symbol," : "",
 		add_dso ? "dso," : "",

tools/perf/builtin-ftrace.c

@@ -0,0 +1,243 @@
+/*
+ * builtin-ftrace.c
+ *
+ * Copyright (c) 2013  LG Electronics,  Namhyung Kim <namhyung@kernel.org>
+ *
+ * Released under the GPL v2.
+ */
+
+#include "builtin.h"
+#include "perf.h"
+
+#include <unistd.h>
+#include <signal.h>
+
+#include "debug.h"
+#include <subcmd/parse-options.h>
+#include "evlist.h"
+#include "target.h"
+#include "thread_map.h"
+
+
+#define DEFAULT_TRACER  "function_graph"
+
+struct perf_ftrace {
+	struct perf_evlist *evlist;
+	struct target target;
+	const char *tracer;
+};
+
+static bool done;
+
+static void sig_handler(int sig __maybe_unused)
+{
+	done = true;
+}
+
+/*
+ * perf_evlist__prepare_workload will send a SIGUSR1 if the fork fails, since
+ * we asked by setting its exec_error to the function below,
+ * ftrace__workload_exec_failed_signal.
+ *
+ * XXX We need to handle this more appropriately, emitting an error, etc.
+ */
+static void ftrace__workload_exec_failed_signal(int signo __maybe_unused,
+						siginfo_t *info __maybe_unused,
+						void *ucontext __maybe_unused)
+{
+	/* workload_exec_errno = info->si_value.sival_int; */
+	done = true;
+}
+
+static int write_tracing_file(const char *name, const char *val)
+{
+	char *file;
+	int fd, ret = -1;
+	ssize_t size = strlen(val);
+
+	file = get_tracing_file(name);
+	if (!file) {
+		pr_debug("cannot get tracing file: %s\n", name);
+		return -1;
+	}
+
+	fd = open(file, O_WRONLY);
+	if (fd < 0) {
+		pr_debug("cannot open tracing file: %s\n", name);
+		goto out;
+	}
+
+	if (write(fd, val, size) == size)
+		ret = 0;
+	else
+		pr_debug("write '%s' to tracing/%s failed\n", val, name);
+
+	close(fd);
+out:
+	put_tracing_file(file);
+	return ret;
+}
+
+static int reset_tracing_files(struct perf_ftrace *ftrace __maybe_unused)
+{
+	if (write_tracing_file("tracing_on", "0") < 0)
+		return -1;
+
+	if (write_tracing_file("current_tracer", "nop") < 0)
+		return -1;
+
+	if (write_tracing_file("set_ftrace_pid", " ") < 0)
+		return -1;
+
+	return 0;
+}
+
+static int __cmd_ftrace(struct perf_ftrace *ftrace, int argc, const char **argv)
+{
+	char *trace_file;
+	int trace_fd;
+	char *trace_pid;
+	char buf[4096];
+	struct pollfd pollfd = {
+		.events = POLLIN,
+	};
+
+	if (geteuid() != 0) {
+		pr_err("ftrace only works for root!\n");
+		return -1;
+	}
+
+	if (argc < 1)
+		return -1;
+
+	signal(SIGINT, sig_handler);
+	signal(SIGUSR1, sig_handler);
+	signal(SIGCHLD, sig_handler);
+
+	reset_tracing_files(ftrace);
+
+	/* reset ftrace buffer */
+	if (write_tracing_file("trace", "0") < 0)
+		goto out;
+
+	if (perf_evlist__prepare_workload(ftrace->evlist, &ftrace->target,
+					  argv, false, ftrace__workload_exec_failed_signal) < 0)
+		goto out;
+
+	if (write_tracing_file("current_tracer", ftrace->tracer) < 0) {
+		pr_err("failed to set current_tracer to %s\n", ftrace->tracer);
+		goto out;
+	}
+
+	if (asprintf(&trace_pid, "%d", thread_map__pid(ftrace->evlist->threads, 0)) < 0) {
+		pr_err("failed to allocate pid string\n");
+		goto out;
+	}
+
+	if (write_tracing_file("set_ftrace_pid", trace_pid) < 0) {
+		pr_err("failed to set pid: %s\n", trace_pid);
+		goto out_free_pid;
+	}
+
+	trace_file = get_tracing_file("trace_pipe");
+	if (!trace_file) {
+		pr_err("failed to open trace_pipe\n");
+		goto out_free_pid;
+	}
+
+	trace_fd = open(trace_file, O_RDONLY);
+
+	put_tracing_file(trace_file);
+
+	if (trace_fd < 0) {
+		pr_err("failed to open trace_pipe\n");
+		goto out_free_pid;
+	}
+
+	fcntl(trace_fd, F_SETFL, O_NONBLOCK);
+	pollfd.fd = trace_fd;
+
+	if (write_tracing_file("tracing_on", "1") < 0) {
+		pr_err("can't enable tracing\n");
+		goto out_close_fd;
+	}
+
+	perf_evlist__start_workload(ftrace->evlist);
+
+	while (!done) {
+		if (poll(&pollfd, 1, -1) < 0)
+			break;
+
+		if (pollfd.revents & POLLIN) {
+			int n = read(trace_fd, buf, sizeof(buf));
+			if (n < 0)
+				break;
+			if (fwrite(buf, n, 1, stdout) != 1)
+				break;
+		}
+	}
+
+	write_tracing_file("tracing_on", "0");
+
+	/* read remaining buffer contents */
+	while (true) {
+		int n = read(trace_fd, buf, sizeof(buf));
+		if (n <= 0)
+			break;
+		if (fwrite(buf, n, 1, stdout) != 1)
+			break;
+	}
+
+out_close_fd:
+	close(trace_fd);
+out_free_pid:
+	free(trace_pid);
+out:
+	reset_tracing_files(ftrace);
+
+	return done ? 0 : -1;
+}
+
+int cmd_ftrace(int argc, const char **argv, const char *prefix __maybe_unused)
+{
+	int ret;
+	struct perf_ftrace ftrace = {
+		.tracer = "function_graph",
+		.target = { .uid = UINT_MAX, },
+	};
+	const char * const ftrace_usage[] = {
+		"perf ftrace [<options>] <command>",
+		"perf ftrace [<options>] -- <command> [<options>]",
+		NULL
+	};
+	const struct option ftrace_options[] = {
+	OPT_STRING('t', "tracer", &ftrace.tracer, "tracer",
+		   "tracer to use: function_graph(default) or function"),
+	OPT_INCR('v', "verbose", &verbose,
+		 "be more verbose"),
+	OPT_END()
+	};
+
+	argc = parse_options(argc, argv, ftrace_options, ftrace_usage,
+			    PARSE_OPT_STOP_AT_NON_OPTION);
+	if (!argc)
+		usage_with_options(ftrace_usage, ftrace_options);
+
+	ftrace.evlist = perf_evlist__new();
+	if (ftrace.evlist == NULL)
+		return -ENOMEM;
+
+	ret = perf_evlist__create_maps(ftrace.evlist, &ftrace.target);
+	if (ret < 0)
+		goto out_delete_evlist;
+
+	if (ftrace.tracer == NULL)
+		ftrace.tracer = DEFAULT_TRACER;
+
+	ret = __cmd_ftrace(&ftrace, argc, argv);
+
+out_delete_evlist:
+	perf_evlist__delete(ftrace.evlist);
+
+	return ret;
+}

tools/perf/builtin.h

@@ -41,6 +41,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix);
 int cmd_inject(int argc, const char **argv, const char *prefix);
 int cmd_mem(int argc, const char **argv, const char *prefix);
 int cmd_data(int argc, const char **argv, const char *prefix);
+int cmd_ftrace(int argc, const char **argv, const char *prefix);
 
 int find_scripts(char **scripts_array, char **scripts_path_array);
 #endif

tools/perf/command-list.txt

@@ -11,6 +11,7 @@ perf-data			mainporcelain common
 perf-diff			mainporcelain common
 perf-config			mainporcelain common
 perf-evlist			mainporcelain common
+perf-ftrace			mainporcelain common
 perf-inject			mainporcelain common
 perf-kallsyms			mainporcelain common
 perf-kmem			mainporcelain common

tools/perf/perf.c

@@ -71,6 +71,7 @@ static struct cmd_struct commands[] = {
 	{ "inject",	cmd_inject,	0 },
 	{ "mem",	cmd_mem,	0 },
 	{ "data",	cmd_data,	0 },
+	{ "ftrace",	cmd_ftrace,	0 },
 };
 
 struct pager_config {

tools/perf/tests/llvm.c

@@ -13,7 +13,7 @@ static int test__bpf_parsing(void *obj_buf, size_t obj_buf_sz)
 	struct bpf_object *obj;
 
 	obj = bpf_object__open_buffer(obj_buf, obj_buf_sz, NULL);
-	if (IS_ERR(obj))
+	if (libbpf_get_error(obj))
 		return TEST_FAIL;
 	bpf_object__close(obj);
 	return TEST_OK;

tools/perf/ui/browsers/hists.c

@@ -501,8 +501,8 @@ static int hierarchy_set_folding(struct hist_browser *hb, struct hist_entry *he,
 	return n;
 }
 
-static void hist_entry__set_folding(struct hist_entry *he,
-				    struct hist_browser *hb, bool unfold)
+static void __hist_entry__set_folding(struct hist_entry *he,
+				      struct hist_browser *hb, bool unfold)
 {
 	hist_entry__init_have_children(he);
 	he->unfolded = unfold ? he->has_children : false;
@@ -520,12 +520,34 @@ static void hist_entry__set_folding(struct hist_entry *he,
 		he->nr_rows = 0;
 }
 
+static void hist_entry__set_folding(struct hist_entry *he,
+				    struct hist_browser *browser, bool unfold)
+{
+	double percent;
+
+	percent = hist_entry__get_percent_limit(he);
+	if (he->filtered || percent < browser->min_pcnt)
+		return;
+
+	__hist_entry__set_folding(he, browser, unfold);
+
+	if (!he->depth || unfold)
+		browser->nr_hierarchy_entries++;
+	if (he->leaf)
+		browser->nr_callchain_rows += he->nr_rows;
+	else if (unfold && !hist_entry__has_hierarchy_children(he, browser->min_pcnt)) {
+		browser->nr_hierarchy_entries++;
+		he->has_no_entry = true;
+		he->nr_rows = 1;
+	} else
+		he->has_no_entry = false;
+}
+
 static void
 __hist_browser__set_folding(struct hist_browser *browser, bool unfold)
 {
 	struct rb_node *nd;
 	struct hist_entry *he;
-	double percent;
 
 	nd = rb_first(&browser->hists->entries);
 	while (nd) {
@@ -535,21 +557,6 @@ __hist_browser__set_folding(struct hist_browser *browser, bool unfold)
 		nd = __rb_hierarchy_next(nd, HMD_FORCE_CHILD);
 
 		hist_entry__set_folding(he, browser, unfold);
-
-		percent = hist_entry__get_percent_limit(he);
-		if (he->filtered || percent < browser->min_pcnt)
-			continue;
-
-		if (!he->depth || unfold)
-			browser->nr_hierarchy_entries++;
-		if (he->leaf)
-			browser->nr_callchain_rows += he->nr_rows;
-		else if (unfold && !hist_entry__has_hierarchy_children(he, browser->min_pcnt)) {
-			browser->nr_hierarchy_entries++;
-			he->has_no_entry = true;
-			he->nr_rows = 1;
-		} else
-			he->has_no_entry = false;
 	}
 }
 
@@ -564,6 +571,15 @@ static void hist_browser__set_folding(struct hist_browser *browser, bool unfold)
 	ui_browser__reset_index(&browser->b);
 }
 
+static void hist_browser__set_folding_selected(struct hist_browser *browser, bool unfold)
+{
+	if (!browser->he_selection)
+		return;
+
+	hist_entry__set_folding(browser->he_selection, browser, unfold);
+	browser->b.nr_entries = hist_browser__nr_entries(browser);
+}
+
 static void ui_browser__warn_lost_events(struct ui_browser *browser)
 {
 	ui_browser__warning(browser, 4,
@@ -637,10 +653,18 @@ int hist_browser__run(struct hist_browser *browser, const char *help)
 			/* Collapse the whole world. */
 			hist_browser__set_folding(browser, false);
 			break;
+		case 'c':
+			/* Collapse the selected entry. */
+			hist_browser__set_folding_selected(browser, false);
+			break;
 		case 'E':
 			/* Expand the whole world. */
 			hist_browser__set_folding(browser, true);
 			break;
+		case 'e':
+			/* Expand the selected entry. */
+			hist_browser__set_folding_selected(browser, true);
+			break;
 		case 'H':
 			browser->show_headers = !browser->show_headers;
 			hist_browser__update_rows(browser);

tools/perf/util/dso.c

@@ -9,6 +9,13 @@
 #include "debug.h"
 #include "vdso.h"
 
+static const char * const debuglink_paths[] = {
+	"%.0s%s",
+	"%s/%s",
+	"%s/.debug/%s",
+	"/usr/lib/debug%s/%s"
+};
+
 char dso__symtab_origin(const struct dso *dso)
 {
 	static const char origin[] = {
@@ -44,24 +51,43 @@ int dso__read_binary_type_filename(const struct dso *dso,
 	size_t len;
 
 	switch (type) {
-	case DSO_BINARY_TYPE__DEBUGLINK: {
-		char *debuglink;
+	case DSO_BINARY_TYPE__DEBUGLINK:
+	{
+		const char *last_slash;
+		char dso_dir[PATH_MAX];
+		char symfile[PATH_MAX];
+		unsigned int i;
 
 		len = __symbol__join_symfs(filename, size, dso->long_name);
-		debuglink = filename + len;
-		while (debuglink != filename && *debuglink != '/')
-			debuglink--;
-		if (*debuglink == '/')
-			debuglink++;
+		last_slash = filename + len;
+		while (last_slash != filename && *last_slash != '/')
+			last_slash--;
 
-		ret = -1;
-		if (!is_regular_file(filename))
+		strncpy(dso_dir, filename, last_slash - filename);
+		dso_dir[last_slash-filename] = '\0';
+
+		if (!is_regular_file(filename)) {
+			ret = -1;
+			break;
+		}
+
+		ret = filename__read_debuglink(filename, symfile, PATH_MAX);
+		if (ret)
 			break;
 
-		ret = filename__read_debuglink(filename, debuglink,
-					       size - (debuglink - filename));
+		/* Check predefined locations where debug file might reside */
+		ret = -1;
+		for (i = 0; i < ARRAY_SIZE(debuglink_paths); i++) {
+			snprintf(filename, size,
+					debuglink_paths[i], dso_dir, symfile);
+			if (is_regular_file(filename)) {
+				ret = 0;
+				break;
+			}
 		}
+
 		break;
+	}
 	case DSO_BINARY_TYPE__BUILD_ID_CACHE:
 		if (dso__build_id_filename(dso, filename, size) == NULL)
 			ret = -1;

tools/perf/util/header.c

@@ -2803,8 +2803,10 @@ static int perf_evsel__prepare_tracepoint_event(struct perf_evsel *evsel,
 	}
 
 	event = pevent_find_event(pevent, evsel->attr.config);
-	if (event == NULL)
+	if (event == NULL) {
+		pr_debug("cannot find event format for %d\n", (int)evsel->attr.config);
 		return -1;
+	}
 
 	if (!evsel->name) {
 		snprintf(bf, sizeof(bf), "%s:%s", event->system, event->name);

tools/perf/util/probe-event.c

@@ -3023,20 +3023,17 @@ static int try_to_find_absolute_address(struct perf_probe_event *pev,
 
 	tev->nargs = pev->nargs;
 	tev->args = zalloc(sizeof(struct probe_trace_arg) * tev->nargs);
-	if (!tev->args) {
-		err = -ENOMEM;
+	if (!tev->args)
 		goto errout;
-	}
+
 	for (i = 0; i < tev->nargs; i++)
 		copy_to_probe_trace_arg(&tev->args[i], &pev->args[i]);
 
 	return 1;
 
 errout:
-	if (*tevs) {
-		clear_probe_trace_events(*tevs, 1);
-		*tevs = NULL;
-	}
+	clear_probe_trace_events(*tevs, 1);
+	*tevs = NULL;
 	return err;
 }
 

tools/perf/util/scripting-engines/trace-event-perl.c

@@ -350,8 +350,10 @@ static void perl_process_tracepoint(struct perf_sample *sample,
 	if (evsel->attr.type != PERF_TYPE_TRACEPOINT)
 		return;
 
-	if (!event)
-		die("ug! no event found for type %" PRIu64, (u64)evsel->attr.config);
+	if (!event) {
+		pr_debug("ug! no event found for type %" PRIu64, (u64)evsel->attr.config);
+		return;
+	}
 
 	pid = raw_field_value(event, "common_pid", data);
 

tools/perf/util/trace-event-info.c

@@ -42,7 +42,7 @@
 #include "evsel.h"
 #include "debug.h"
 
-#define VERSION "0.5"
+#define VERSION "0.6"
 
 static int output_fd;
 
@@ -379,6 +379,34 @@ out:
 	return err;
 }
 
+static int record_saved_cmdline(void)
+{
+	unsigned int size;
+	char *path;
+	struct stat st;
+	int ret, err = 0;
+
+	path = get_tracing_file("saved_cmdlines");
+	if (!path) {
+		pr_debug("can't get tracing/saved_cmdline");
+		return -ENOMEM;
+	}
+
+	ret = stat(path, &st);
+	if (ret < 0) {
+		/* not found */
+		size = 0;
+		if (write(output_fd, &size, 8) != 8)
+			err = -EIO;
+		goto out;
+	}
+	err = record_file(path, 8);
+
+out:
+	put_tracing_file(path);
+	return err;
+}
+
 static void
 put_tracepoints_path(struct tracepoint_path *tps)
 {
@@ -539,6 +567,9 @@ struct tracing_data *tracing_data_get(struct list_head *pattrs,
 	if (err)
 		goto out;
 	err = record_ftrace_printk();
+	if (err)
+		goto out;
+	err = record_saved_cmdline();
 
 out:
 	/*

tools/perf/util/trace-event-parse.c

@@ -160,6 +160,23 @@ void parse_ftrace_printk(struct pevent *pevent,
 	}
 }
 
+void parse_saved_cmdline(struct pevent *pevent,
+			 char *file, unsigned int size __maybe_unused)
+{
+	char *comm;
+	char *line;
+	char *next = NULL;
+	int pid;
+
+	line = strtok_r(file, "\n", &next);
+	while (line) {
+		sscanf(line, "%d %ms", &pid, &comm);
+		pevent_register_comm(pevent, comm, pid);
+		free(comm);
+		line = strtok_r(NULL, "\n", &next);
+	}
+}
+
 int parse_ftrace_file(struct pevent *pevent, char *buf, unsigned long size)
 {
 	return pevent_parse_event(pevent, buf, size, "ftrace");

tools/perf/util/trace-event-read.c

@@ -260,39 +260,53 @@ static int read_header_files(struct pevent *pevent)
 
 static int read_ftrace_file(struct pevent *pevent, unsigned long long size)
 {
+	int ret;
 	char *buf;
 
 	buf = malloc(size);
-	if (buf == NULL)
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
 		return -1;
+	}
 
-	if (do_read(buf, size) < 0) {
-		free(buf);
-		return -1;
+	ret = do_read(buf, size);
+	if (ret < 0) {
+		pr_debug("error reading ftrace file.\n");
+		goto out;
 	}
 
-	parse_ftrace_file(pevent, buf, size);
+	ret = parse_ftrace_file(pevent, buf, size);
+	if (ret < 0)
+		pr_debug("error parsing ftrace file.\n");
+out:
 	free(buf);
-	return 0;
+	return ret;
 }
 
 static int read_event_file(struct pevent *pevent, char *sys,
 			    unsigned long long size)
 {
+	int ret;
 	char *buf;
 
 	buf = malloc(size);
-	if (buf == NULL)
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
 		return -1;
+	}
 
-	if (do_read(buf, size) < 0) {
+	ret = do_read(buf, size);
+	if (ret < 0) {
 		free(buf);
-		return -1;
+		goto out;
 	}
 
-	parse_event_file(pevent, buf, size, sys);
+	ret = parse_event_file(pevent, buf, size, sys);
+	if (ret < 0)
+		pr_debug("error parsing event file.\n");
+out:
 	free(buf);
-	return 0;
+	return ret;
 }
 
 static int read_ftrace_files(struct pevent *pevent)
@@ -341,6 +355,36 @@ static int read_event_files(struct pevent *pevent)
 	return 0;
 }
 
+static int read_saved_cmdline(struct pevent *pevent)
+{
+	unsigned long long size;
+	char *buf;
+	int ret;
+
+	/* it can have 0 size */
+	size = read8(pevent);
+	if (!size)
+		return 0;
+
+	buf = malloc(size + 1);
+	if (buf == NULL) {
+		pr_debug("memory allocation failure\n");
+		return -1;
+	}
+
+	ret = do_read(buf, size);
+	if (ret < 0) {
+		pr_debug("error reading saved cmdlines\n");
+		goto out;
+	}
+
+	parse_saved_cmdline(pevent, buf, size);
+	ret = 0;
+out:
+	free(buf);
+	return ret;
+}
+
 ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
 {
 	char buf[BUFSIZ];
@@ -379,10 +423,11 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
 		return -1;
 	if (show_version)
 		printf("version = %s\n", version);
-	free(version);
 
-	if (do_read(buf, 1) < 0)
+	if (do_read(buf, 1) < 0) {
+		free(version);
 		return -1;
+	}
 	file_bigendian = buf[0];
 	host_bigendian = bigendian();
 
@@ -423,6 +468,11 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
 	err = read_ftrace_printk(pevent);
 	if (err)
 		goto out;
+	if (atof(version) >= 0.6) {
+		err = read_saved_cmdline(pevent);
+		if (err)
+			goto out;
+	}
 
 	size = trace_data_size;
 	repipe = false;
@@ -438,5 +488,6 @@ ssize_t trace_report(int fd, struct trace_event *tevent, bool __repipe)
 out:
 	if (pevent)
 		trace_event__cleanup(tevent);
+	free(version);
 	return size;
 }

tools/perf/util/trace-event.h

@@ -42,6 +42,7 @@ raw_field_value(struct event_format *event, const char *name, void *data);
 
 void parse_proc_kallsyms(struct pevent *pevent, char *file, unsigned int size);
 void parse_ftrace_printk(struct pevent *pevent, char *file, unsigned int size);
+void parse_saved_cmdline(struct pevent *pevent, char *file, unsigned int size);
 
 ssize_t trace_report(int fd, struct trace_event *tevent, bool repipe);
 

tools/perf/util/unwind-libunwind-local.c

@@ -35,6 +35,7 @@
 #include "util.h"
 #include "debug.h"
 #include "asm/bug.h"
+#include "dso.h"
 
 extern int
 UNW_OBJ(dwarf_search_unwind_table) (unw_addr_space_t as,
@@ -297,15 +298,58 @@ static int read_unwind_spec_debug_frame(struct dso *dso,
 	int fd;
 	u64 ofs = dso->data.debug_frame_offset;
 
+	/* debug_frame can reside in:
+	 *  - dso
+	 *  - debug pointed by symsrc_filename
+	 *  - gnu_debuglink, which doesn't necessary
+	 *    has to be pointed by symsrc_filename
+	 */
 	if (ofs == 0) {
 		fd = dso__data_get_fd(dso, machine);
-		if (fd < 0)
-			return -EINVAL;
+		if (fd >= 0) {
+			ofs = elf_section_offset(fd, ".debug_frame");
+			dso__data_put_fd(dso);
+		}
+
+		if (ofs <= 0) {
+			fd = open(dso->symsrc_filename, O_RDONLY);
+			if (fd >= 0) {
+				ofs = elf_section_offset(fd, ".debug_frame");
+				close(fd);
+			}
+		}
+
+		if (ofs <= 0) {
+			char *debuglink = malloc(PATH_MAX);
+			int ret = 0;
+
+			ret = dso__read_binary_type_filename(
+				dso, DSO_BINARY_TYPE__DEBUGLINK,
+				machine->root_dir, debuglink, PATH_MAX);
+			if (!ret) {
+				fd = open(debuglink, O_RDONLY);
+				if (fd >= 0) {
+					ofs = elf_section_offset(fd,
+							".debug_frame");
+					close(fd);
+				}
+			}
+			if (ofs > 0) {
+				if (dso->symsrc_filename != NULL) {
+					pr_warning(
+						"%s: overwrite symsrc(%s,%s)\n",
+							__func__,
+							dso->symsrc_filename,
+							debuglink);
+					free(dso->symsrc_filename);
+				}
+				dso->symsrc_filename = debuglink;
+			} else {
+				free(debuglink);
+			}
+		}
 
-		/* Check the .debug_frame section for unwinding info */
-		ofs = elf_section_offset(fd, ".debug_frame");
 		dso->data.debug_frame_offset = ofs;
-		dso__data_put_fd(dso);
 	}
 
 	*offset = ofs;