[PATCH v3 4/5] perf-probe: Find versioned symbols from map
From: Masami Hiramatsu <mhiramat@kernel.org>
Date: 2017-12-08 16:29:54
Also in:
linux-perf-users, lkml
Subsystem:
performance events subsystem, the rest · Maintainers:
Peter Zijlstra, Ingo Molnar, Arnaldo Carvalho de Melo, Namhyung Kim, Linus Torvalds
Find versioned symbols correctly from map.
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)
=====
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Thomas Richter <redacted>
Acked-by: Ravi Bangoria <redacted>
---
Changes in v3:
- Fix to return -ENOMEM if strndup fails.
- Fix to check name != NULL before refering it in
arch__normalize_symbol_name() for ppc.
---
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(-)
diff --git a/tools/perf/arch/powerpc/util/sym-handling.c b/tools/perf/arch/powerpc/util/sym-handling.c
index 9c4e23d8c8ce..53d83d7e6a09 100644
--- a/tools/perf/arch/powerpc/util/sym-handling.c
+++ b/tools/perf/arch/powerpc/util/sym-handling.c@@ -64,6 +64,14 @@ int arch__compare_symbol_names_n(const char *namea, const char *nameb, 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
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index a68141d360b0..0d6c66d51939 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c@@ -2801,16 +2801,32 @@ static int find_probe_functions(struct map *map, char *name, 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;
@@ -2856,7 +2872,7 @@ static int find_probe_trace_events_from_map(struct perf_probe_event *pev, * 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;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 1b67a8639dfe..cc065d4bfafc 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c@@ -94,6 +94,11 @@ static int prefix_underscores_count(const char *str) 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);
diff --git a/tools/perf/util/symbol.h b/tools/perf/util/symbol.h
index a4f0075b4e5c..0563f33c1eb3 100644
--- a/tools/perf/util/symbol.h
+++ b/tools/perf/util/symbol.h@@ -349,6 +349,7 @@ bool elf__needs_adjust_symbols(GElf_Ehdr 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