[PATCH -tip 12/14] perf probe: Check build-id of vmlinux

Masami Hiramatsu
2009-12-15T15:29:18Z

Check build-id of vmlinux by using functions in symbol.c.
This also exposes map__load() for getting vmlinux path,
and removes vmlinux path list in builtin-probe.c,
because symbol.c already has that. Checking build-id
prevents users to open old or different debuginfo from
current running kernel.

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 | 72 ++++++++++++++++++--------------------------
tools/perf/util/event.h | 2 +
tools/perf/util/map.c | 14 ++++++---
3 files changed, 41 insertions(+), 47 deletions(-)

diff --git a/tools/perf/builtin-probe.c b/tools/perf/builtin-probe.c
index 4d232cb..5008605 100644
--- a/tools/perf/builtin-probe.c
+++ b/tools/perf/builtin-probe.c
@@ -38,33 +38,27 @@
#include "util/strlist.h"
#include "util/event.h"
#include "util/debug.h"
+#include "util/symbol.h"
+#include "util/thread.h"
+#include "util/session.h"
#include "util/parse-options.h"
#include "util/parse-events.h" /* For debugfs_path */
#include "util/probe-finder.h"
#include "util/probe-event.h"

-/* Default vmlinux search paths */
-#define NR_SEARCH_PATH 4
-const char *default_search_path[NR_SEARCH_PATH] = {
-"/lib/modules/%s/build/vmlinux", /* Custom build kernel */
-"/usr/lib/debug/lib/modules/%s/vmlinux", /* Red Hat debuginfo */
-"/boot/vmlinux-debug-%s", /* Ubuntu */
-"./vmlinux", /* CWD */
-};
-
#define MAX_PATH_LEN 256
#define MAX_PROBES 128

/* Session management structure */
static struct {
- char *vmlinux;
- char *release;
bool need_dwarf;
bool list_events;
bool force_add;
int nr_probe;
struct probe_point probes[MAX_PROBES];
struct strlist *dellist;
+ struct symbol_conf conf;
+ struct perf_session *psession;
} session;

@@ -122,33 +116,21 @@ static int opt_del_probe_event(const struct option *opt __used,
}

#ifndef NO_LIBDWARF
-static int open_default_vmlinux(void)
+static int open_vmlinux(void)
{
- struct utsname uts;
- char fname[MAX_PATH_LEN];
- int fd, ret, i;
-
- ret = uname(&uts);
- if (ret) {
- pr_debug("uname() failed.\n");
- return -errno;
+ 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;
}
- session.release = uts.release;
- for (i = 0; i < NR_SEARCH_PATH; i++) {
- ret = snprintf(fname, MAX_PATH_LEN,
- default_search_path[i], session.release);
- if (ret >= MAX_PATH_LEN || ret < 0) {
- pr_debug("Filename(%d,%s) is too long.\n", i,
- uts.release);
- errno = E2BIG;
- return -E2BIG;
- }
- pr_debug("try to open %s\n", fname);
- fd = open(fname, O_RDONLY);
- if (fd >= 0)
- break;
+ if (map__load(kmap, session.psession, NULL) < 0) {
+ pr_debug("Failed to load kernel map.\n");
+ return -EINVAL;
}
- return fd;
+ pr_debug("Try to open %s\n", kmap->dso->long_name);
+ return open(kmap->dso->long_name, O_RDONLY);
}
#endif

@@ -164,8 +146,8 @@ static const struct option options[] = {
OPT_BOOLEAN('v', "verbose", &verbose,
"be more verbose (show parsed arguments, etc)"),
#ifndef NO_LIBDWARF
- OPT_STRING('k', "vmlinux", &session.vmlinux, "file",
- "vmlinux/module pathname"),
+ OPT_STRING('k', "vmlinux", &session.conf.vmlinux_name,
+ "file", "vmlinux pathname"),
#endif
OPT_BOOLEAN('l', "list", &session.list_events,
"list up current probe events"),
@@ -236,17 +218,23 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
return 0;
}

+ /* Initialize symbol maps for vmlinux */
+ if (session.conf.vmlinux_name == NULL)
+ session.conf.try_vmlinux_path = true;
+ if (symbol__init(&session.conf) < 0)
+ die("Failed to init symbol map.");
+ session.psession = perf_session__new(NULL, O_WRONLY, false,
+ &session.conf);
+ if (session.psession == NULL)
+ die("Failed to init perf_session.");
+
if (session.need_dwarf)
#ifdef NO_LIBDWARF
die("Debuginfo-analysis is not supported");
#else /* !NO_LIBDWARF */
pr_debug("Some probes require debuginfo.\n");

- if (session.vmlinux) {
- pr_debug("Try to open %s.", session.vmlinux);
- fd = open(session.vmlinux, O_RDONLY);
- } else
- fd = open_default_vmlinux();
+ fd = open_vmlinux();
if (fd < 0) {
if (session.need_dwarf)
die("Could not open debuginfo file.");
diff --git a/tools/perf/util/event.h b/tools/perf/util/event.h
index a92e0b0..8027309 100644
--- a/tools/perf/util/event.h
+++ b/tools/perf/util/event.h
@@ -152,6 +152,8 @@ size_t map__fprintf(struct map *self, FILE *fp);

struct perf_session;

+int map__load(struct map *self, struct perf_session *session,
+ symbol_filter_t filter);
struct symbol *map__find_symbol(struct map *self, struct perf_session *session,
u64 addr, symbol_filter_t filter);
struct symbol *map__find_symbol_by_name(struct map *self, const char *name,
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 8b3dd46..c4d55a0 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -104,12 +104,16 @@ void map__fixup_end(struct map *self)

#define DSO__DELETED "(deleted)"

-static int map__load(struct map *self, struct perf_session *session,
- symbol_filter_t filter)
+int map__load(struct map *self, struct perf_session *session,
+ symbol_filter_t filter)
{
const char *name = self->dso->long_name;
- int nr = dso__load(self->dso, self, session, filter);
+ int nr;

+ if (dso__loaded(self->dso, self->type))
+ return 0;
+
+ nr = dso__load(self->dso, self, session, filter);
if (nr < 0) {
if (self->dso->has_build_id) {
char sbuild_id[BUILD_ID_SIZE * 2 + 1];
@@ -147,7 +151,7 @@ static int map__load(struct map *self, struct perf_session *session,
struct symbol *map__find_symbol(struct map *self, struct perf_session *session,
u64 addr, symbol_filter_t filter)
{
- if (!dso__loaded(self->dso, self->type) && map__load(self, session, filter) < 0)
+ if (map__load(self, session, filter) < 0)
return NULL;

return dso__find_symbol(self->dso, self->type, addr);
@@ -157,7 +161,7 @@ struct symbol *map__find_symbol_by_name(struct map *self, const char *name,
struct perf_session *session,
symbol_filter_t filter)
{
- if (!dso__loaded(self->dso, self->type) && map__load(self, session, filter) < 0)
+ if (map__load(self, session, filter) < 0)
return NULL;

if (!dso__sorted_by_name(self->dso, self->type))