[PATCH -tip 13/14] perf probe: Check symbols in symtab/kallsyms

Masami Hiramatsu
2009-12-15T15:29:46Z

Check symbols in symtab/kallsyms when no debuginfo
is available.

e.g.

# perf probe test
Fatal: Kernel symbol 'test' not found - probe not added.

Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
---

tools/perf/builtin-probe.c | 32 ++++++++++++++++++++++----------
1 files changed, 22 insertions(+), 10 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 5008605..f019536 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -59,6 +59,7 @@ static struct {
struct strlist *dellist;
struct symbol_conf conf;
struct perf_session *psession;
+ struct map *kmap;
} session;

@@ -115,22 +116,26 @@ static int opt_del_probe_event(const struct option *opt __used,
return 0;
}

+/* Currently just checking function name from symbol map */
+static void evaluate_probe_point(struct probe_point *pp)
+{
+ struct symbol *sym;
+ sym = map__find_symbol_by_name(session.kmap, pp->function,
+ session.psession, NULL);
+ if (!sym)
+ die("Kernel symbol \'%s\' not found - probe not added.",
+ pp->function);
+}
+
#ifndef NO_LIBDWARF
static int open_vmlinux(void)
{
- struct map *kmap;
- kmap = map_groups__find_by_name(&session.psession->kmaps,
- MAP__FUNCTION, "[kernel.kallsyms]");
- if (!kmap) {
- pr_debug("Could not find kernel map.\n");
- return -ENOENT;
- }
- if (map__load(kmap, session.psession, NULL) < 0) {
+ if (map__load(session.kmap, session.psession, NULL) < 0) {
pr_debug("Failed to load kernel map.\n");
return -EINVAL;
}
- pr_debug("Try to open %s\n", kmap->dso->long_name);
- return open(kmap->dso->long_name, O_RDONLY);
+ pr_debug("Try to open %s\n", session.kmap->dso->long_name);
+ return open(session.kmap->dso->long_name, O_RDONLY);
}
#endif

@@ -219,6 +224,7 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
}

/* Initialize symbol maps for vmlinux */
+ session.conf.sort_by_name = true;
if (session.conf.vmlinux_name == NULL)
session.conf.try_vmlinux_path = true;
if (symbol__init(&session.conf) < 0)
@@ -227,6 +233,11 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
&session.conf);
if (session.psession == NULL)
die("Failed to init perf_session.");
+ session.kmap = map_groups__find_by_name(&session.psession->kmaps,
+ MAP__FUNCTION,
+ "[kernel.kallsyms]");
+ if (!session.kmap)
+ die("Could not find kernel map.\n");

if (session.need_dwarf)
#ifdef NO_LIBDWARF
@@ -279,6 +290,7 @@ end_dwarf:
if (pp->found) /* This probe is already found. */
continue;

+ evaluate_probe_point(pp);
ret = synthesize_trace_kprobe_event(pp);
if (ret == -E2BIG)
die("probe point definition becomes too long.");