perf symbols: Add symfs option for off-box analysis using specified tree

The symfs argument allows analysis of perf.data file using a locally accessible filesystem tree with debug symbols - e.g., tree created during image builds, sshfs mount, loop mounted KVM disk images, USB keys, initrds, etc. Anything with an OS tree can be analyzed from anywhere without the need to populate a local data store with build-ids. Commiter notes: o Fixed up symfs="/" variants handling. o prefixed DSO__ORIG_GUEST_KMODULE case with symfs too, avoiding use of files outside the symfs directory. LKML-Reference: <1291926427-28846-1-git-send-email-daahern@cisco.com> Signed-off-by: David Ahern <daahern@cisco.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf symbols: Add symfs option for off-box analysis using specified tree
The symfs argument allows analysis of perf.data file using a locally accessible filesystem tree with debug symbols - e.g., tree created during image builds, sshfs mount, loop mounted KVM disk images, USB keys, initrds, etc. Anything with an OS tree can be analyzed from anywhere without the need to populate a local data store with build-ids. Commiter notes: o Fixed up symfs="/" variants handling. o prefixed DSO__ORIG_GUEST_KMODULE case with symfs too, avoiding use of files outside the symfs directory. LKML-Reference: <1291926427-28846-1-git-send-email-daahern@cisco.com> Signed-off-by: David Ahern <daahern@cisco.com> Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
David Ahern · Arnaldo Carvalho de Melo
1 parent eac23d1c38
Showing 9 changed files with 81 additions and 19 deletions Side-by-side Diff
tools/perf/Documentation/perf-diff.txt
tools/perf/Documentation/perf-report.txt
tools/perf/Documentation/perf-timechart.txt
tools/perf/builtin-diff.c
tools/perf/builtin-report.c
tools/perf/builtin-timechart.c
tools/perf/util/hist.c
tools/perf/util/symbol.c
tools/perf/util/symbol.h
@@ -66,6 +66,8 @@
 --force::
        Don't complain, do it.
  
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
  
 SEE ALSO
 --------
@@ -116,6 +116,9 @@
 --force::
         Don't complain, do it.
  
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
+
 SEE ALSO
 --------
 linkperf:perf-stat[1]
@@ -38,6 +38,8 @@
 --process::
         Select the processes to display, by name or PID
  
+--symfs=<directory>::
+        Look for files with symbols relative to this directory.
  
 SEE ALSO
 --------
@@ -194,6 +194,8 @@
 	OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
 		   "separator for columns, no spaces will be added between "
 		   "columns '.' is reserved."),
+	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+		    "Look for files with symbols relative to this directory"),
 	OPT_END()
 };
  
@@ -483,6 +483,8 @@
 		   "columns '.' is reserved."),
 	OPT_BOOLEAN('U', "hide-unresolved", &hide_unresolved,
 		    "Only display entries resolved to a symbol"),
+	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+		    "Look for files with symbols relative to this directory"),
 	OPT_END()
 };
  
@@ -1022,6 +1022,8 @@
 	OPT_CALLBACK('p', "process", NULL, "process",
 		      "process selector. Pass a pid or process name.",
 		       parse_process),
+	OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
+		    "Look for files with symbols relative to this directory"),
 	OPT_END()
 };
  
@@ -1092,7 +1092,13 @@
 	FILE *file;
 	int err = 0;
 	u64 len;
+	char symfs_filename[PATH_MAX];
  
+	if (filename) {
+		snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
+			 symbol_conf.symfs, filename);
+	}
+
 	if (filename == NULL) {
 		if (dso->has_build_id) {
 			pr_err("Can't annotate %s: not enough memory\n",
  
@@ -1100,9 +1106,9 @@
 			return -ENOMEM;
 		}
 		goto fallback;
-	} else if (readlink(filename, command, sizeof(command)) < 0 ||
+	} else if (readlink(symfs_filename, command, sizeof(command)) < 0 ||
 		   strstr(command, "[kernel.kallsyms]") ||
-		   access(filename, R_OK)) {
+		   access(symfs_filename, R_OK)) {
 		free(filename);
 fallback:
 		/*
@@ -1111,6 +1117,8 @@
 		 * DSO is the same as when 'perf record' ran.
 		 */
 		filename = dso->long_name;
+		snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
+			 symbol_conf.symfs, filename);
 		free_filename = false;
 	}
  
@@ -1137,7 +1145,7 @@
 		 "objdump --start-address=0x%016Lx --stop-address=0x%016Lx -dS -C %s|grep -v %s|expand",
 		 map__rip_2objdump(map, sym->start),
 		 map__rip_2objdump(map, sym->end),
-		 filename, filename);
+		 symfs_filename, filename);
  
 	pr_debug("Executing: %s\n", command);
  
@@ -41,6 +41,7 @@
 	.exclude_other	  = true,
 	.use_modules	  = true,
 	.try_vmlinux_path = true,
+	.symfs            = "",
 };
  
 int dso__name_len(const struct dso *self)
  
@@ -839,8 +840,11 @@
 	char sympltname[1024];
 	Elf *elf;
 	int nr = 0, symidx, fd, err = 0;
+	char name[PATH_MAX];
  
-	fd = open(self->long_name, O_RDONLY);
+	snprintf(name, sizeof(name), "%s%s",
+		 symbol_conf.symfs, self->long_name);
+	fd = open(name, O_RDONLY);
 	if (fd < 0)
 		goto out;
  
  
  
  
@@ -1452,16 +1456,19 @@
 	     self->origin++) {
 		switch (self->origin) {
 		case DSO__ORIG_BUILD_ID_CACHE:
-			if (dso__build_id_filename(self, name, size) == NULL)
+			/* skip the locally configured cache if a symfs is given */
+			if (symbol_conf.symfs[0] ||
+			    (dso__build_id_filename(self, name, size) == NULL)) {
 				continue;
+			}
 			break;
 		case DSO__ORIG_FEDORA:
-			snprintf(name, size, "/usr/lib/debug%s.debug",
-				 self->long_name);
+			snprintf(name, size, "%s/usr/lib/debug%s.debug",
+				 symbol_conf.symfs, self->long_name);
 			break;
 		case DSO__ORIG_UBUNTU:
-			snprintf(name, size, "/usr/lib/debug%s",
-				 self->long_name);
+			snprintf(name, size, "%s/usr/lib/debug%s",
+				 symbol_conf.symfs, self->long_name);
 			break;
 		case DSO__ORIG_BUILDID: {
 			char build_id_hex[BUILD_ID_SIZE * 2 + 1];
  
  
  
@@ -1473,21 +1480,28 @@
 					  sizeof(self->build_id),
 					  build_id_hex);
 			snprintf(name, size,
-				 "/usr/lib/debug/.build-id/%.2s/%s.debug",
-				 build_id_hex, build_id_hex + 2);
+				 "%s/usr/lib/debug/.build-id/%.2s/%s.debug",
+				 symbol_conf.symfs, build_id_hex, build_id_hex + 2);
 			}
 			break;
 		case DSO__ORIG_DSO:
-			snprintf(name, size, "%s", self->long_name);
+			snprintf(name, size, "%s%s",
+			     symbol_conf.symfs, self->long_name);
 			break;
 		case DSO__ORIG_GUEST_KMODULE:
 			if (map->groups && map->groups->machine)
 				root_dir = map->groups->machine->root_dir;
 			else
 				root_dir = "";
-			snprintf(name, size, "%s%s", root_dir, self->long_name);
+			snprintf(name, size, "%s%s%s", symbol_conf.symfs,
+				 root_dir, self->long_name);
 			break;
  
+		case DSO__ORIG_KMODULE:
+			snprintf(name, size, "%s%s", symbol_conf.symfs,
+				 self->long_name);
+			break;
+
 		default:
 			/*
 			 * If we wanted a full symtab but no image had one,
  
  
  
@@ -1784,17 +1798,20 @@
 			     const char *vmlinux, symbol_filter_t filter)
 {
 	int err = -1, fd;
+	char symfs_vmlinux[PATH_MAX];
  
-	fd = open(vmlinux, O_RDONLY);
+	snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s/%s",
+		 symbol_conf.symfs, vmlinux);
+	fd = open(symfs_vmlinux, O_RDONLY);
 	if (fd < 0)
 		return -1;
  
 	dso__set_loaded(self, map->type);
-	err = dso__load_sym(self, map, vmlinux, fd, filter, 0, 0);
+	err = dso__load_sym(self, map, symfs_vmlinux, fd, filter, 0, 0);
 	close(fd);
  
 	if (err > 0)
-		pr_debug("Using %s for symbols\n", vmlinux);
+		pr_debug("Using %s for symbols\n", symfs_vmlinux);
  
 	return err;
 }
@@ -1872,6 +1889,10 @@
 			goto out_fixup;
 	}
  
+	/* do not try local files if a symfs was given */
+	if (symbol_conf.symfs[0] != 0)
+		return -1;
+
 	/*
 	 * Say the kernel DSO was created when processing the build-id header table,
 	 * we have a build-id, so check if it is the same as the running kernel,
@@ -2262,9 +2283,6 @@
 	struct utsname uts;
 	char bf[PATH_MAX];
  
-	if (uname(&uts) < 0)
-		return -1;
-
 	vmlinux_path = malloc(sizeof(char *) * 5);
 	if (vmlinux_path == NULL)
 		return -1;
@@ -2277,6 +2295,14 @@
 	if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
 		goto out_fail;
 	++vmlinux_path__nr_entries;
+
+	/* only try running kernel version if no symfs was given */
+	if (symbol_conf.symfs[0] != 0)
+		return 0;
+
+	if (uname(&uts) < 0)
+		return -1;
+
 	snprintf(bf, sizeof(bf), "/boot/vmlinux-%s", uts.release);
 	vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
 	if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
@@ -2336,6 +2362,8 @@
  
 int symbol__init(void)
 {
+	const char *symfs;
+
 	if (symbol_conf.initialized)
 		return 0;
  
@@ -2363,6 +2391,18 @@
 	if (setup_list(&symbol_conf.sym_list,
 		       symbol_conf.sym_list_str, "symbol") < 0)
 		goto out_free_comm_list;
+
+	/*
+	 * A path to symbols of "/" is identical to ""
+	 * reset here for simplicity.
+	 */
+	symfs = realpath(symbol_conf.symfs, NULL);
+	if (symfs == NULL)
+		symfs = symbol_conf.symfs;
+	if (strcmp(symfs, "/") == 0)
+		symbol_conf.symfs = "";
+	if (symfs != symbol_conf.symfs)
+		free((void *)symfs);
  
 	symbol_conf.initialized = true;
 	return 0;
@@ -86,6 +86,7 @@
        struct strlist	*dso_list,
 			*comm_list,
 			*sym_list;
+	const char	*symfs;
 };
  
 extern struct symbol_conf symbol_conf;
...	...	@@ -66,6 +66,8 @@
66	66	--force::
67	67	Don't complain, do it.
68	68
	69	+--symfs=<directory>::
	70	+ Look for files with symbols relative to this directory.
69	71
70	72	SEE ALSO
71	73	--------
...	...	@@ -116,6 +116,9 @@
116	116	--force::
117	117	Don't complain, do it.
118	118
	119	+--symfs=<directory>::
	120	+ Look for files with symbols relative to this directory.
	121	+
119	122	SEE ALSO
120	123	--------
121	124	linkperf:perf-stat[1]
...	...	@@ -38,6 +38,8 @@
38	38	--process::
39	39	Select the processes to display, by name or PID
40	40
	41	+--symfs=<directory>::
	42	+ Look for files with symbols relative to this directory.
41	43
42	44	SEE ALSO
43	45	--------
...	...	@@ -194,6 +194,8 @@
194	194	OPT_STRING('t', "field-separator", &symbol_conf.field_sep, "separator",
195	195	"separator for columns, no spaces will be added between "
196	196	"columns '.' is reserved."),
	197	+ OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
	198	+ "Look for files with symbols relative to this directory"),
197	199	OPT_END()
198	200	};
199	201
...	...	@@ -483,6 +483,8 @@
483	483	"columns '.' is reserved."),
484	484	OPT_BOOLEAN('U', "hide-unresolved", &hide_unresolved,
485	485	"Only display entries resolved to a symbol"),
	486	+ OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
	487	+ "Look for files with symbols relative to this directory"),
486	488	OPT_END()
487	489	};
488	490
...	...	@@ -1022,6 +1022,8 @@
1022	1022	OPT_CALLBACK('p', "process", NULL, "process",
1023	1023	"process selector. Pass a pid or process name.",
1024	1024	parse_process),
	1025	+ OPT_STRING(0, "symfs", &symbol_conf.symfs, "directory",
	1026	+ "Look for files with symbols relative to this directory"),
1025	1027	OPT_END()
1026	1028	};
1027	1029
...	...	@@ -1092,7 +1092,13 @@
1092	1092	FILE *file;
1093	1093	int err = 0;
1094	1094	u64 len;
	1095	+ char symfs_filename[PATH_MAX];
1095	1096
	1097	+ if (filename) {
	1098	+ snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
	1099	+ symbol_conf.symfs, filename);
	1100	+ }
	1101	+
1096	1102	if (filename == NULL) {
1097	1103	if (dso->has_build_id) {
1098	1104	pr_err("Can't annotate %s: not enough memory\n",
1099	1105
...	...	@@ -1100,9 +1106,9 @@
1100	1106	return -ENOMEM;
1101	1107	}
1102	1108	goto fallback;
1103		- } else if (readlink(filename, command, sizeof(command)) < 0 \|\|
	1109	+ } else if (readlink(symfs_filename, command, sizeof(command)) < 0 \|\|
1104	1110	strstr(command, "[kernel.kallsyms]") \|\|
1105		- access(filename, R_OK)) {
	1111	+ access(symfs_filename, R_OK)) {
1106	1112	free(filename);
1107	1113	fallback:
1108	1114	/*
...	...	@@ -1111,6 +1117,8 @@
1111	1117	* DSO is the same as when 'perf record' ran.
1112	1118	*/
1113	1119	filename = dso->long_name;
	1120	+ snprintf(symfs_filename, sizeof(symfs_filename), "%s%s",
	1121	+ symbol_conf.symfs, filename);
1114	1122	free_filename = false;
1115	1123	}
1116	1124
...	...	@@ -1137,7 +1145,7 @@
1137	1145	"objdump --start-address=0x%016Lx --stop-address=0x%016Lx -dS -C %s\|grep -v %s\|expand",
1138	1146	map__rip_2objdump(map, sym->start),
1139	1147	map__rip_2objdump(map, sym->end),
1140		- filename, filename);
	1148	+ symfs_filename, filename);
1141	1149
1142	1150	pr_debug("Executing: %s\n", command);
1143	1151
...	...	@@ -41,6 +41,7 @@
41	41	.exclude_other = true,
42	42	.use_modules = true,
43	43	.try_vmlinux_path = true,
	44	+ .symfs = "",
44	45	};
45	46
46	47	int dso__name_len(const struct dso *self)
47	48
...	...	@@ -839,8 +840,11 @@
839	840	char sympltname[1024];
840	841	Elf *elf;
841	842	int nr = 0, symidx, fd, err = 0;
	843	+ char name[PATH_MAX];
842	844
843		- fd = open(self->long_name, O_RDONLY);
	845	+ snprintf(name, sizeof(name), "%s%s",
	846	+ symbol_conf.symfs, self->long_name);
	847	+ fd = open(name, O_RDONLY);
844	848	if (fd < 0)
845	849	goto out;
846	850
847	851
848	852
849	853
...	...	@@ -1452,16 +1456,19 @@
1452	1456	self->origin++) {
1453	1457	switch (self->origin) {
1454	1458	case DSO__ORIG_BUILD_ID_CACHE:
1455		- if (dso__build_id_filename(self, name, size) == NULL)
	1459	+ /* skip the locally configured cache if a symfs is given */
	1460	+ if (symbol_conf.symfs[0] \|\|
	1461	+ (dso__build_id_filename(self, name, size) == NULL)) {
1456	1462	continue;
	1463	+ }
1457	1464	break;
1458	1465	case DSO__ORIG_FEDORA:
1459		- snprintf(name, size, "/usr/lib/debug%s.debug",
1460		- self->long_name);
	1466	+ snprintf(name, size, "%s/usr/lib/debug%s.debug",
	1467	+ symbol_conf.symfs, self->long_name);
1461	1468	break;
1462	1469	case DSO__ORIG_UBUNTU:
1463		- snprintf(name, size, "/usr/lib/debug%s",
1464		- self->long_name);
	1470	+ snprintf(name, size, "%s/usr/lib/debug%s",
	1471	+ symbol_conf.symfs, self->long_name);
1465	1472	break;
1466	1473	case DSO__ORIG_BUILDID: {
1467	1474	char build_id_hex[BUILD_ID_SIZE * 2 + 1];
1468	1475
1469	1476
1470	1477
...	...	@@ -1473,21 +1480,28 @@
1473	1480	sizeof(self->build_id),
1474	1481	build_id_hex);
1475	1482	snprintf(name, size,
1476		- "/usr/lib/debug/.build-id/%.2s/%s.debug",
1477		- build_id_hex, build_id_hex + 2);
	1483	+ "%s/usr/lib/debug/.build-id/%.2s/%s.debug",
	1484	+ symbol_conf.symfs, build_id_hex, build_id_hex + 2);
1478	1485	}
1479	1486	break;
1480	1487	case DSO__ORIG_DSO:
1481		- snprintf(name, size, "%s", self->long_name);
	1488	+ snprintf(name, size, "%s%s",
	1489	+ symbol_conf.symfs, self->long_name);
1482	1490	break;
1483	1491	case DSO__ORIG_GUEST_KMODULE:
1484	1492	if (map->groups && map->groups->machine)
1485	1493	root_dir = map->groups->machine->root_dir;
1486	1494	else
1487	1495	root_dir = "";
1488		- snprintf(name, size, "%s%s", root_dir, self->long_name);
	1496	+ snprintf(name, size, "%s%s%s", symbol_conf.symfs,
	1497	+ root_dir, self->long_name);
1489	1498	break;
1490	1499
	1500	+ case DSO__ORIG_KMODULE:
	1501	+ snprintf(name, size, "%s%s", symbol_conf.symfs,
	1502	+ self->long_name);
	1503	+ break;
	1504	+
1491	1505	default:
1492	1506	/*
1493	1507	* If we wanted a full symtab but no image had one,
1494	1508
1495	1509
1496	1510
...	...	@@ -1784,17 +1798,20 @@
1784	1798	const char *vmlinux, symbol_filter_t filter)
1785	1799	{
1786	1800	int err = -1, fd;
	1801	+ char symfs_vmlinux[PATH_MAX];
1787	1802
1788		- fd = open(vmlinux, O_RDONLY);
	1803	+ snprintf(symfs_vmlinux, sizeof(symfs_vmlinux), "%s/%s",
	1804	+ symbol_conf.symfs, vmlinux);
	1805	+ fd = open(symfs_vmlinux, O_RDONLY);
1789	1806	if (fd < 0)
1790	1807	return -1;
1791	1808
1792	1809	dso__set_loaded(self, map->type);
1793		- err = dso__load_sym(self, map, vmlinux, fd, filter, 0, 0);
	1810	+ err = dso__load_sym(self, map, symfs_vmlinux, fd, filter, 0, 0);
1794	1811	close(fd);
1795	1812
1796	1813	if (err > 0)
1797		- pr_debug("Using %s for symbols\n", vmlinux);
	1814	+ pr_debug("Using %s for symbols\n", symfs_vmlinux);
1798	1815
1799	1816	return err;
1800	1817	}
...	...	@@ -1872,6 +1889,10 @@
1872	1889	goto out_fixup;
1873	1890	}
1874	1891
	1892	+ /* do not try local files if a symfs was given */
	1893	+ if (symbol_conf.symfs[0] != 0)
	1894	+ return -1;
	1895	+
1875	1896	/*
1876	1897	* Say the kernel DSO was created when processing the build-id header table,
1877	1898	* we have a build-id, so check if it is the same as the running kernel,
...	...	@@ -2262,9 +2283,6 @@
2262	2283	struct utsname uts;
2263	2284	char bf[PATH_MAX];
2264	2285
2265		- if (uname(&uts) < 0)
2266		- return -1;
2267		-
2268	2286	vmlinux_path = malloc(sizeof(char ) 5);
2269	2287	if (vmlinux_path == NULL)
2270	2288	return -1;
...	...	@@ -2277,6 +2295,14 @@
2277	2295	if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
2278	2296	goto out_fail;
2279	2297	++vmlinux_path__nr_entries;
	2298	+
	2299	+ /* only try running kernel version if no symfs was given */
	2300	+ if (symbol_conf.symfs[0] != 0)
	2301	+ return 0;
	2302	+
	2303	+ if (uname(&uts) < 0)
	2304	+ return -1;
	2305	+
2280	2306	snprintf(bf, sizeof(bf), "/boot/vmlinux-%s", uts.release);
2281	2307	vmlinux_path[vmlinux_path__nr_entries] = strdup(bf);
2282	2308	if (vmlinux_path[vmlinux_path__nr_entries] == NULL)
...	...	@@ -2336,6 +2362,8 @@
2336	2362
2337	2363	int symbol__init(void)
2338	2364	{
	2365	+ const char *symfs;
	2366	+
2339	2367	if (symbol_conf.initialized)
2340	2368	return 0;
2341	2369
...	...	@@ -2363,6 +2391,18 @@
2363	2391	if (setup_list(&symbol_conf.sym_list,
2364	2392	symbol_conf.sym_list_str, "symbol") < 0)
2365	2393	goto out_free_comm_list;
	2394	+
	2395	+ /*
	2396	+ * A path to symbols of "/" is identical to ""
	2397	+ * reset here for simplicity.
	2398	+ */
	2399	+ symfs = realpath(symbol_conf.symfs, NULL);
	2400	+ if (symfs == NULL)
	2401	+ symfs = symbol_conf.symfs;
	2402	+ if (strcmp(symfs, "/") == 0)
	2403	+ symbol_conf.symfs = "";
	2404	+ if (symfs != symbol_conf.symfs)
	2405	+ free((void *)symfs);
2366	2406
2367	2407	symbol_conf.initialized = true;
2368	2408	return 0;
...	...	@@ -86,6 +86,7 @@
86	86	struct strlist *dso_list,
87	87	*comm_list,
88	88	*sym_list;
	89	+ const char *symfs;
89	90	};
90	91
91	92	extern struct symbol_conf symbol_conf;