perf symbols: Allow user probes on versioned symbols

Symbol versioning, as in glibc, results in symbols being defined as: <real symbol>@[@]<version> (Note that "@@" identifies a default symbol, if the symbol name is repeated.) perf is currently unable to deal with this, and is unable to create user probes at such symbols: -- $ nm /lib/powerpc64le-linux-gnu/libpthread.so.0 | grep pthread_create 0000000000008d30 t __pthread_create_2_1 0000000000008d30 T pthread_create@@GLIBC_2.17 $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create probe-definition(0): pthread_create symbol:pthread_create file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Open Debuginfo file: /usr/lib/debug/lib/powerpc64le-linux-gnu/libpthread-2.19.so Try to find probe point from debuginfo. Probe point 'pthread_create' not found. Error: Failed to add events. Reason: No such file or directory (Code: -2) -- One is not able to specify the fully versioned symbol, either, due to syntactic conflicts with other uses of "@" by perf: -- $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create@@GLIBC_2.17 probe-definition(0): pthread_create@@GLIBC_2.17 Semantic error :SRC@SRC is not allowed. 0 arguments Error: Command Parse Error. Reason: Invalid argument (Code: -22) -- This patch ignores versioning for default symbols, thus allowing probes to be created for these symbols: -- $ /usr/bin/sudo ./perf probe -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create Added new event: probe_libpthread:pthread_create (on pthread_create in /lib/powerpc64le-linux-gnu/libpthread-2.19.so) You can now use it in all perf tools, such as: perf record -e probe_libpthread:pthread_create -aR sleep 1 $ /usr/bin/sudo ./perf record -e probe_libpthread:pthread_create -aR ./test 2 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.052 MB perf.data (2 samples) ] $ /usr/bin/sudo ./perf script test 2915 [000] 19124.260729: probe_libpthread:pthread_create: (3fff99248d38) test 2916 [000] 19124.260962: probe_libpthread:pthread_create: (3fff99248d38) $ /usr/bin/sudo ./perf probe --del=probe_libpthread:pthread_create Removed event: probe_libpthread:pthread_create -- Committer note: Change the variable storing the result of strlen() to 'int', to fix the build on debian:experimental-x-mipsel, fedora:24-x-ARC-uClibc, ubuntu:16.04-x-arm, etc: util/symbol.c: In function 'symbol__match_symbol_name': util/symbol.c:422:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (len < versioning - name) ^ Signed-off-by: Paul A. Clarke <pc@us.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: David Ahern <dsahern@gmail.com> Link: http://lkml.kernel.org/r/c2b18d9c-17f8-9285-4868-f58b6359ccac@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

perf symbols: Allow user probes on versioned symbols
Symbol versioning, as in glibc, results in symbols being defined as: <real symbol>@[@]<version> (Note that "@@" identifies a default symbol, if the symbol name is repeated.) perf is currently unable to deal with this, and is unable to create user probes at such symbols: -- $ nm /lib/powerpc64le-linux-gnu/libpthread.so.0 | grep pthread_create 0000000000008d30 t __pthread_create_2_1 0000000000008d30 T pthread_create@@GLIBC_2.17 $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create probe-definition(0): pthread_create symbol:pthread_create file:(null) line:0 offset:0 return:0 lazy:(null) 0 arguments Open Debuginfo file: /usr/lib/debug/lib/powerpc64le-linux-gnu/libpthread-2.19.so Try to find probe point from debuginfo. Probe point 'pthread_create' not found. Error: Failed to add events. Reason: No such file or directory (Code: -2) -- One is not able to specify the fully versioned symbol, either, due to syntactic conflicts with other uses of "@" by perf: -- $ /usr/bin/sudo perf probe -v -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create@@GLIBC_2.17 probe-definition(0): pthread_create@@GLIBC_2.17 Semantic error :SRC@SRC is not allowed. 0 arguments Error: Command Parse Error. Reason: Invalid argument (Code: -22) -- This patch ignores versioning for default symbols, thus allowing probes to be created for these symbols: -- $ /usr/bin/sudo ./perf probe -x /lib/powerpc64le-linux-gnu/libpthread.so.0 pthread_create Added new event: probe_libpthread:pthread_create (on pthread_create in /lib/powerpc64le-linux-gnu/libpthread-2.19.so) You can now use it in all perf tools, such as: perf record -e probe_libpthread:pthread_create -aR sleep 1 $ /usr/bin/sudo ./perf record -e probe_libpthread:pthread_create -aR ./test 2 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.052 MB perf.data (2 samples) ] $ /usr/bin/sudo ./perf script test 2915 [000] 19124.260729: probe_libpthread:pthread_create: (3fff99248d38) test 2916 [000] 19124.260962: probe_libpthread:pthread_create: (3fff99248d38) $ /usr/bin/sudo ./perf probe --del=probe_libpthread:pthread_create Removed event: probe_libpthread:pthread_create -- Committer note: Change the variable storing the result of strlen() to 'int', to fix the build on debian:experimental-x-mipsel, fedora:24-x-ARC-uClibc, ubuntu:16.04-x-arm, etc: util/symbol.c: In function 'symbol__match_symbol_name': util/symbol.c:422:11: error: comparison between signed and unsigned integer expressions [-Werror=sign-compare] if (len < versioning - name) ^ Signed-off-by: Paul A. Clarke <pc@us.ibm.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Cc: David Ahern <dsahern@gmail.com> Link: http://lkml.kernel.org/r/c2b18d9c-17f8-9285-4868-f58b6359ccac@us.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Paul Clarke · Arnaldo Carvalho de Melo
1 parent b843f62ad9
Showing 5 changed files with 74 additions and 20 deletions Side-by-side Diff
tools/perf/arch/powerpc/util/sym-handling.c
tools/perf/util/map.c
tools/perf/util/map.h
tools/perf/util/symbol.c
tools/perf/util/symbol.h
@@ -52,6 +52,18 @@
  
 	return strcmp(namea, nameb);
 }
+
+int arch__compare_symbol_names_n(const char *namea, const char *nameb,
+				 unsigned int n)
+{
+	/* Skip over initial dot */
+	if (*namea == '.')
+		namea++;
+	if (*nameb == '.')
+		nameb++;
+
+	return strncmp(namea, nameb, n);
+}
 #endif
  
 #if defined(_CALL_ELF) && _CALL_ELF == 2
@@ -325,11 +325,6 @@
 	return 0;
 }
  
-int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
-{
-	return strcmp(namea, nameb);
-}
-
 struct symbol *map__find_symbol(struct map *map, u64 addr)
 {
 	if (map__load(map) < 0)
@@ -130,13 +130,14 @@
  */
 #define __map__for_each_symbol_by_name(map, sym_name, pos)	\
 	for (pos = map__find_symbol_by_name(map, sym_name);	\
-	     pos && arch__compare_symbol_names(pos->name, sym_name) == 0;	\
+	     pos &&						\
+	     !symbol__match_symbol_name(pos->name, sym_name,	\
+					SYMBOL_TAG_INCLUDE__DEFAULT_ONLY); \
 	     pos = symbol__next_by_name(pos))
  
 #define map__for_each_symbol_by_name(map, sym_name, pos)		\
 	__map__for_each_symbol_by_name(map, sym_name, (pos))
  
-int arch__compare_symbol_names(const char *namea, const char *nameb);
 void map__init(struct map *map, enum map_type type,
 	       u64 start, u64 end, u64 pgoff, struct dso *dso);
 struct map *map__new(struct machine *machine, u64 start, u64 len,
@@ -90,6 +90,17 @@
 	return tail - str;
 }
  
+int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
+{
+	return strcmp(namea, nameb);
+}
+
+int __weak arch__compare_symbol_names_n(const char *namea, const char *nameb,
+					unsigned int n)
+{
+	return strncmp(namea, nameb, n);
+}
+
 int __weak arch__choose_best_symbol(struct symbol *syma,
 				    struct symbol *symb __maybe_unused)
 {
  
@@ -399,8 +410,26 @@
 	}
 }
  
+int symbol__match_symbol_name(const char *name, const char *str,
+			      enum symbol_tag_include includes)
+{
+	const char *versioning;
+
+	if (includes == SYMBOL_TAG_INCLUDE__DEFAULT_ONLY &&
+	    (versioning = strstr(name, "@@"))) {
+		int len = strlen(str);
+
+		if (len < versioning - name)
+			len = versioning - name;
+
+		return arch__compare_symbol_names_n(name, str, len);
+	} else
+		return arch__compare_symbol_names(name, str);
+}
+
 static struct symbol *symbols__find_by_name(struct rb_root *symbols,
-					    const char *name)
+					    const char *name,
+					    enum symbol_tag_include includes)
 {
 	struct rb_node *n;
 	struct symbol_name_rb_node *s = NULL;
  
  
@@ -414,11 +443,11 @@
 		int cmp;
  
 		s = rb_entry(n, struct symbol_name_rb_node, rb_node);
-		cmp = arch__compare_symbol_names(name, s->sym.name);
+		cmp = symbol__match_symbol_name(s->sym.name, name, includes);
  
-		if (cmp < 0)
+		if (cmp > 0)
 			n = n->rb_left;
-		else if (cmp > 0)
+		else if (cmp < 0)
 			n = n->rb_right;
 		else
 			break;
  
  
@@ -427,16 +456,17 @@
 	if (n == NULL)
 		return NULL;
  
-	/* return first symbol that has same name (if any) */
-	for (n = rb_prev(n); n; n = rb_prev(n)) {
-		struct symbol_name_rb_node *tmp;
+	if (includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY)
+		/* return first symbol that has same name (if any) */
+		for (n = rb_prev(n); n; n = rb_prev(n)) {
+			struct symbol_name_rb_node *tmp;
  
-		tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
-		if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
-			break;
+			tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
+			if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
+				break;
  
-		s = tmp;
-	}
+			s = tmp;
+		}
  
 	return &s->sym;
 }
@@ -503,7 +533,12 @@
 struct symbol *dso__find_symbol_by_name(struct dso *dso, enum map_type type,
 					const char *name)
 {
-	return symbols__find_by_name(&dso->symbol_names[type], name);
+	struct symbol *s = symbols__find_by_name(&dso->symbol_names[type], name,
+						 SYMBOL_TAG_INCLUDE__NONE);
+	if (!s)
+		s = symbols__find_by_name(&dso->symbol_names[type], name,
+					  SYMBOL_TAG_INCLUDE__DEFAULT_ONLY);
+	return s;
 }
  
 void dso__sort_by_name(struct dso *dso, enum map_type type)
@@ -348,7 +348,18 @@
 #define SYMBOL_A 0
 #define SYMBOL_B 1
  
+int arch__compare_symbol_names(const char *namea, const char *nameb);
+int arch__compare_symbol_names_n(const char *namea, const char *nameb,
+				 unsigned int n);
 int arch__choose_best_symbol(struct symbol *syma, struct symbol *symb);
+
+enum symbol_tag_include {
+	SYMBOL_TAG_INCLUDE__NONE = 0,
+	SYMBOL_TAG_INCLUDE__DEFAULT_ONLY
+};
+
+int symbol__match_symbol_name(const char *namea, const char *nameb,
+			      enum symbol_tag_include includes);
  
 /* structure containing an SDT note's info */
 struct sdt_note {
...	...	@@ -52,6 +52,18 @@
52	52
53	53	return strcmp(namea, nameb);
54	54	}
	55	+
	56	+int arch__compare_symbol_names_n(const char namea, const char nameb,
	57	+ unsigned int n)
	58	+{
	59	+ /* Skip over initial dot */
	60	+ if (*namea == '.')
	61	+ namea++;
	62	+ if (*nameb == '.')
	63	+ nameb++;
	64	+
	65	+ return strncmp(namea, nameb, n);
	66	+}
55	67	#endif
56	68
57	69	#if defined(_CALL_ELF) && _CALL_ELF == 2
...	...	@@ -325,11 +325,6 @@
325	325	return 0;
326	326	}
327	327
328		-int __weak arch__compare_symbol_names(const char namea, const char nameb)
329		-{
330		- return strcmp(namea, nameb);
331		-}
332		-
333	328	struct symbol map__find_symbol(struct map map, u64 addr)
334	329	{
335	330	if (map__load(map) < 0)
...	...	@@ -130,13 +130,14 @@
130	130	*/
131	131	#define __map__for_each_symbol_by_name(map, sym_name, pos) \
132	132	for (pos = map__find_symbol_by_name(map, sym_name); \
133		- pos && arch__compare_symbol_names(pos->name, sym_name) == 0; \
	133	+ pos && \
	134	+ !symbol__match_symbol_name(pos->name, sym_name, \
	135	+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY); \
134	136	pos = symbol__next_by_name(pos))
135	137
136	138	#define map__for_each_symbol_by_name(map, sym_name, pos) \
137	139	__map__for_each_symbol_by_name(map, sym_name, (pos))
138	140
139		-int arch__compare_symbol_names(const char namea, const char nameb);
140	141	void map__init(struct map *map, enum map_type type,
141	142	u64 start, u64 end, u64 pgoff, struct dso *dso);
142	143	struct map map__new(struct machine machine, u64 start, u64 len,
...	...	@@ -90,6 +90,17 @@
90	90	return tail - str;
91	91	}
92	92
	93	+int __weak arch__compare_symbol_names(const char namea, const char nameb)
	94	+{
	95	+ return strcmp(namea, nameb);
	96	+}
	97	+
	98	+int __weak arch__compare_symbol_names_n(const char namea, const char nameb,
	99	+ unsigned int n)
	100	+{
	101	+ return strncmp(namea, nameb, n);
	102	+}
	103	+
93	104	int __weak arch__choose_best_symbol(struct symbol *syma,
94	105	struct symbol *symb __maybe_unused)
95	106	{
96	107
...	...	@@ -399,8 +410,26 @@
399	410	}
400	411	}
401	412
	413	+int symbol__match_symbol_name(const char name, const char str,
	414	+ enum symbol_tag_include includes)
	415	+{
	416	+ const char *versioning;
	417	+
	418	+ if (includes == SYMBOL_TAG_INCLUDE__DEFAULT_ONLY &&
	419	+ (versioning = strstr(name, "@@"))) {
	420	+ int len = strlen(str);
	421	+
	422	+ if (len < versioning - name)
	423	+ len = versioning - name;
	424	+
	425	+ return arch__compare_symbol_names_n(name, str, len);
	426	+ } else
	427	+ return arch__compare_symbol_names(name, str);
	428	+}
	429	+
402	430	static struct symbol symbols__find_by_name(struct rb_root symbols,
403		- const char *name)
	431	+ const char *name,
	432	+ enum symbol_tag_include includes)
404	433	{
405	434	struct rb_node *n;
406	435	struct symbol_name_rb_node *s = NULL;
407	436
408	437
...	...	@@ -414,11 +443,11 @@
414	443	int cmp;
415	444
416	445	s = rb_entry(n, struct symbol_name_rb_node, rb_node);
417		- cmp = arch__compare_symbol_names(name, s->sym.name);
	446	+ cmp = symbol__match_symbol_name(s->sym.name, name, includes);
418	447
419		- if (cmp < 0)
	448	+ if (cmp > 0)
420	449	n = n->rb_left;
421		- else if (cmp > 0)
	450	+ else if (cmp < 0)
422	451	n = n->rb_right;
423	452	else
424	453	break;
425	454
426	455
...	...	@@ -427,16 +456,17 @@
427	456	if (n == NULL)
428	457	return NULL;
429	458
430		- /* return first symbol that has same name (if any) */
431		- for (n = rb_prev(n); n; n = rb_prev(n)) {
432		- struct symbol_name_rb_node *tmp;
	459	+ if (includes != SYMBOL_TAG_INCLUDE__DEFAULT_ONLY)
	460	+ /* return first symbol that has same name (if any) */
	461	+ for (n = rb_prev(n); n; n = rb_prev(n)) {
	462	+ struct symbol_name_rb_node *tmp;
433	463
434		- tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
435		- if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
436		- break;
	464	+ tmp = rb_entry(n, struct symbol_name_rb_node, rb_node);
	465	+ if (arch__compare_symbol_names(tmp->sym.name, s->sym.name))
	466	+ break;
437	467
438		- s = tmp;
439		- }
	468	+ s = tmp;
	469	+ }
440	470
441	471	return &s->sym;
442	472	}
...	...	@@ -503,7 +533,12 @@
503	533	struct symbol dso__find_symbol_by_name(struct dso dso, enum map_type type,
504	534	const char *name)
505	535	{
506		- return symbols__find_by_name(&dso->symbol_names[type], name);
	536	+ struct symbol *s = symbols__find_by_name(&dso->symbol_names[type], name,
	537	+ SYMBOL_TAG_INCLUDE__NONE);
	538	+ if (!s)
	539	+ s = symbols__find_by_name(&dso->symbol_names[type], name,
	540	+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY);
	541	+ return s;
507	542	}
508	543
509	544	void dso__sort_by_name(struct dso *dso, enum map_type type)
...	...	@@ -348,7 +348,18 @@
348	348	#define SYMBOL_A 0
349	349	#define SYMBOL_B 1
350	350
	351	+int arch__compare_symbol_names(const char namea, const char nameb);
	352	+int arch__compare_symbol_names_n(const char namea, const char nameb,
	353	+ unsigned int n);
351	354	int arch__choose_best_symbol(struct symbol syma, struct symbol symb);
	355	+
	356	+enum symbol_tag_include {
	357	+ SYMBOL_TAG_INCLUDE__NONE = 0,
	358	+ SYMBOL_TAG_INCLUDE__DEFAULT_ONLY
	359	+};
	360	+
	361	+int symbol__match_symbol_name(const char namea, const char nameb,
	362	+ enum symbol_tag_include includes);
352	363
353	364	/* structure containing an SDT note's info */
354	365	struct sdt_note {