Patch "perf probe: Find versioned symbols from map" has been added to the 4.15-stable tree

This is a note to let you know that I've just added the patch titled

perf probe: Find versioned symbols from map

to the 4.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
perf-probe-find-versioned-symbols-from-map.patch
and it can be found in the queue-4.15 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Masami Hiramatsu <[email protected]>
Date: Sat, 9 Dec 2017 01:28:12 +0900
Subject: perf probe: Find versioned symbols from map

From: Masami Hiramatsu <[email protected]>

[ Upstream commit 4b3a2716dd785fabb9f6ac80c1d53cb29a88169d ]

Commit d80406453ad4 ("perf symbols: Allow user probes on versioned symbols") allows user to find default versioned symbols (with "@@") in map. However, it did not enable normal versioned symbol (with "@") for perf-probe. E.g.

=====

  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Failed to find symbol malloc_get_state in /usr/lib64/libc-2.25.so
    Error: Failed to add events.
  =====

This solves above issue by improving perf-probe symbol search function, as below.

=====

  # ./perf probe -x /lib64/libc-2.25.so malloc_get_state
  Added new event:
    probe_libc:malloc_get_state (on malloc_get_state in /usr/lib64/libc-2.25.so)

You can now use it in all perf tools, such as:

perf record -e probe_libc:malloc_get_state -aR sleep 1

  # ./perf probe -l
    probe_libc:malloc_get_state (on malloc_get_state@GLIBC_2.2.5 in /usr/lib64/libc-2.25.so)
  =====

---
 tools/perf/arch/powerpc/util/sym-handling.c |    8 ++++++++
 tools/perf/util/probe-event.c               |   20 ++++++++++++++++++--
 tools/perf/util/symbol.c                    |    5 +++++
 tools/perf/util/symbol.h                    |    1 +
 4 files changed, 32 insertions(+), 2 deletions(-)

@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const c
 
 	return strncmp(namea, nameb, n);
 }
+
+const char *arch__normalize_symbol_name(const char *name)
+{
+	/* Skip over initial dot */
+	if (name && *name == '.')
+		name++;
+	return name;
+}
 #endif
 
 #if defined(_CALL_ELF) && _CALL_ELF == 2

@@ -2792,16 +2792,32 @@ static int find_probe_functions(struct m
 	int found = 0;
 	struct symbol *sym;
 	struct rb_node *tmp;
+	const char *norm, *ver;
+	char *buf = NULL;
 
 	if (map__load(map) < 0)
 		return 0;
 
 	map__for_each_symbol(map, sym, tmp) {
-		if (strglobmatch(sym->name, name)) {
+		norm = arch__normalize_symbol_name(sym->name);
+		if (!norm)
+			continue;
+
+		/* We don't care about default symbol or not */
+		ver = strchr(norm, '@');
+		if (ver) {
+			buf = strndup(norm, ver - norm);
+			if (!buf)
+				return -ENOMEM;
+			norm = buf;
+		}
+		if (strglobmatch(norm, name)) {
 			found++;
 			if (syms && found < probe_conf.max_probes)
 				syms[found - 1] = sym;
 		}
+		if (buf)
+			zfree(&buf);
 	}
 
 	return found;

@@ -2847,7 +2863,7 @@ static int find_probe_trace_events_from_
 	 * same name but different addresses, this lists all the symbols.
 	 */
 	num_matched_functions = find_probe_functions(map, pp->function, syms);
-	if (num_matched_functions == 0) {
+	if (num_matched_functions <= 0) {
 		pr_err("Failed to find symbol %s in %s\n", pp->function,
 			pev->target ? : "kernel");
 		ret = -ENOENT;

@@ -94,6 +94,11 @@ static int prefix_underscores_count(cons
 	return tail - str;
 }
 
+const char * __weak arch__normalize_symbol_name(const char *name)
+{
+	return name;
+}
+
 int __weak arch__compare_symbol_names(const char *namea, const char *nameb)
 {
 	return strcmp(namea, nameb);

@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr
 void arch__sym_update(struct symbol *s, GElf_Sym *sym);
 #endif
 
+const char *arch__normalize_symbol_name(const char *name);
 #define SYMBOL_A 0
 #define SYMBOL_B 1
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.15/perf-probe-find-versioned-symbols-from-map.patch queue-4.15/perf-probe-add-warning-message-if-there-is-unexpected-event-name.patch