[PATCH 22/25] perf buildid-cache: Add support to add build ids from perf data

Jiri Olsa
2020-11-26T17:02:35Z

Adding support to specify perf data file as -a option file
argument,

If the file is detected to be perf data file, it is processed
and all dso objects with sample hit are stored to the build
id cache.

$ DEBUGINFOD_URLS=http://192.168.122.174:8002 perf buildid-cache -a perf.data
OK 5dcec522abf136fcfd3128f47e131f2365834dd7 /home/jolsa/.debug/.build-id/5d/cec522abf136fcfd3128f47e131f2365834dd7/elf
OK 5784f813b727a50cfd3363234aef9fcbab685cc4 /lib/modules/5.10.0-rc2speed+/kernel/fs/xfs/xfs.ko

By default we store only dso with hits, but it's possible to
specify 'all' to store all dso objects, like:
-a perf.data,all

$ DEBUGINFOD_URLS=http://192.168.122.174:8002 perf buildid-cache -a perf.data,all
OK 5dcec522abf136fcfd3128f47e131f2365834dd7 /home/jolsa/.debug/.build-id/5d/cec522abf136fcfd3128f47e131f2365834dd7/elf
OK 6ce92dc7c31f12fe5b7775a2bb8b14a3546ce2cd /lib/modules/5.10.0-rc2speed+/kernel/drivers/firmware/qemu_fw_cfg.ko
OK bf3f6d32dccc159f841fc3658c241d0e74c61fbb /lib/modules/5.10.0-rc2speed+/kernel/drivers/block/virtio_blk.ko
OK e896b4329cf9f190f1a0fae933f425ff8f71b052 /lib/modules/5.10.0-rc2speed+/kernel/drivers/char/virtio_console.ko
OK 5bedc933cb59e053ecb472f327bd73c548364479 /lib/modules/5.10.0-rc2speed+/kernel/drivers/input/serio/serio_raw.ko
OK cecc506368a8b7a473a5f900d26f0d3d914a9c23 /lib/modules/5.10.0-rc2speed+/kernel/arch/x86/crypto/crc32c-intel.ko
OK 91076fb3646d061a0a42cf7bddb339a665ee4f80 /lib/modules/5.10.0-rc2speed+/kernel/arch/x86/crypto/ghash-clmulni-intel.ko
OK 4e2a304d788bb8e2e950bc82a5944e042afa0bf2 /lib/modules/5.10.0-rc2speed+/kernel/drivers/media/cec/core/cec.ko
OK 31ab0da5ad81e6803280177f507a95f3053d585e /lib/modules/5.10.0-rc2speed+/kernel/lib/libcrc32c.ko
OK f6154bca47c149f48c942fcc3d653041dd285c65 /lib/modules/5.10.0-rc2speed+/kernel/drivers/gpu/drm/ttm/ttm.ko
OK 723f5852de81590d54b23b38c160d3618b41951b /lib/modules/5.10.0-rc2speed+/kernel/arch/x86/crypto/crct10dif-pclmul.ko
OK 06b1eab7f141cbc3e5a5db47909c8ab5cb242e40 /lib/modules/5.10.0-rc2speed+/kernel/drivers/gpu/drm/drm_ttm_helper.ko
OK 38292b862cf3ff87489508fdb4895efa45780813 /lib/modules/5.10.0-rc2speed+/kernel/drivers/gpu/drm/qxl/qxl.ko
OK cdf51e58609bf2ce4837a7b195e0ccae0a930907 /lib/modules/5.10.0-rc2speed+/kernel/arch/x86/crypto/crc32-pclmul.ko
OK 5ca8958388f6688452ecc2cb83d6031394c659ad /lib/modules/5.10.0-rc2speed+/kernel/drivers/gpu/drm/drm.ko
OK 236bc4e4f38bf3559007566cb32b3dcc1bc28d2d /lib/modules/5.10.0-rc2speed+/kernel/drivers/gpu/drm/drm_kms_helper.ko
OK 5784f813b727a50cfd3363234aef9fcbab685cc4 /lib/modules/5.10.0-rc2speed+/kernel/fs/xfs/xfs.ko
OK 66db2be3efaa43bb5a5c481986e9554e1885cc69 /usr/lib/systemd/systemd
OK 7db607d9f2de89860d9639712da64c8bacd31e4b /usr/lib64/libm-2.30.so
OK 55b5f9652e1d17c1dd58f62628d5063428e5db91 /usr/lib64/libudev.so.1.6.15
OK 63b97070bf097130713bb6c89cf7100b5f3c9b17 /usr/lib64/libunistring.so.2.1.0
...

Once perf data is specified, no other file can be specified in
the option, otherwise it causes syntax error.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
.../perf/Documentation/perf-buildid-cache.txt | 12 +-
tools/perf/builtin-buildid-cache.c | 213 +++++++++++++++++-
tools/perf/util/probe-event.c | 6 +-
3 files changed, 225 insertions(+), 6 deletions(-)

diff --git a/tools/perf/Documentation/perf-buildid-cache.txt b/tools/perf/Documentation/perf-buildid-cache.txt
index f6de0952ff3c..b77da5138bca 100644
--- a/tools/perf/Documentation/perf-buildid-cache.txt
+++ b/tools/perf/Documentation/perf-buildid-cache.txt
@@ -23,7 +23,17 @@ OPTIONS
-------
-a::
--add=::
- Add specified file to the cache.
+ Add specified file or perf.data binaries to the cache.
+
+ If the file is detected to be perf data file, it is processed
+ and all dso objects with sample hit are stored to the cache.
+
+ It's possible to specify 'all' to store all dso objects, like:
+ -a perf.data,all
+
+ Once perf data is specified, no other file can be specified in
+ the option, otherwise it causes syntax error.
+
-f::
--force::
Don't complain, do it.
diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index a25411926e48..f0afb2c89e03 100644
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -29,6 +29,11 @@
#include "util/probe-file.h"
#include <linux/string.h>
#include <linux/err.h>
+#include <linux/zalloc.h>
+#include <sys/stat.h>
+#ifdef HAVE_DEBUGINFOD_SUPPORT
+#include <elfutils/debuginfod.h>
+#endif

static int build_id_cache__kcore_buildid(const char *proc_dir, char *sbuildid)
{
@@ -348,6 +353,203 @@ static int build_id_cache__show_all(void)
return 0;
}

+#ifdef HAVE_DEBUGINFOD_SUPPORT
+static int call_debuginfod(const char *sbuild_id, char **path, bool debuginfo)
+{
+ debuginfod_client *c;
+ int fd;
+
+ c = debuginfod_begin();
+ if (c == NULL)
+ return -1;
+
+ pr_debug("trying debuginfod for executable <%s> ... ", sbuild_id);
+
+ if (debuginfo) {
+ fd = debuginfod_find_debuginfo(c, (const unsigned char *) sbuild_id,
+ 0, path);
+ } else {
+ fd = debuginfod_find_executable(c, (const unsigned char *) sbuild_id,
+ 0, path);
+ }
+ if (fd >= 0)
+ close(fd); /* retaining reference by realname */
+
+ debuginfod_end(c);
+ pr_debug("%s%s\n", *path ? "OK " : "FAILED", *path ? *path : "");
+ return *path ? 0 : -1;
+}
+#else
+static int call_debuginfod(const char *sbuild_id __maybe_unused,
+ char **path __maybe_unused,
+ bool debuginfo __maybe_unused)
+{
+ return -1;
+}
+#endif
+
+struct dso_store_data {
+ bool hits;
+};
+
+static int dso_store(struct dso *dso, struct machine *machine, void *priv)
+{
+ struct dso_store_data *data = priv;
+ char sbuild_id[SBUILD_ID_SIZE];
+ struct build_id bid;
+ char *path = NULL, *link = NULL;
+ bool is_kallsyms;
+ int err = -1;
+
+ /*
+ * There's no build id in dso, nothing to do..
+ */
+ if (!dso->has_build_id || !build_id__is_defined(&dso->bid))
+ return 0;
+
+ if (data->hits && !dso->hit)
+ return 0;
+
+ /*
+ * The storing process is:
+ * - get build id of the dso
+ * - check if it is already in cache
+ * - check if it matches provided build id from mmap2 event
+ * - if not, try debuginfod to download the binary
+ * - store binary to build id database
+ */
+ is_kallsyms = !strcmp(machine->mmap_name, dso->short_name);
+ build_id__sprintf(&dso->bid, sbuild_id);
+
+ link = build_id_cache__linkname(sbuild_id, NULL, 0);
+ if (!link)
+ return -ENOMEM;
+
+ if (!access(link, X_OK)) {
+ pr_debug("already in cache - %s <%s>\n", dso->long_name, sbuild_id);
+ err = 0;
+ goto out;
+ }
+
+ path = strdup(dso->long_name);
+ if (!path)
+ goto out;
+
+ if (is_kallsyms) {
+ /*
+ * Find out if we are on the same kernel as perf.data
+ * and store kallsyms in that case.
+ */
+ err = sysfs__read_build_id("/sys/kernel/notes", &bid);
+ if (err < 0)
+ goto out;
+ } else {
+ struct nscookie nsc;
+ struct stat st;
+
+ nsinfo__mountns_enter(dso->nsinfo, &nsc);
+
+ /*
+ * Does the file exists in the first place, if it does,
+ * resolve path and read the build id.
+ */
+ if (stat(dso->long_name, &st)) {
+ nsinfo__mountns_exit(&nsc);
+ zfree(&path);
+ goto try_download;
+ }
+
+ err = filename__read_build_id(dso->long_name, &bid);
+ nsinfo__mountns_exit(&nsc);
+
+ if (err <= 0)
+ goto out;
+ }
+
+ /*
+ * If we match, then what we want in mmap2 event
+ * is what we got in the binary,
+ */
+ if (bid.size != dso->bid.size || memcmp(&bid, &dso->bid, bid.size)) {
+ char sbid[SBUILD_ID_SIZE];
+
+ build_id__sprintf(&bid, sbid);
+ pr_debug("mmap build id <%s> does not match for %s <%s>\n",
+ sbuild_id, path, sbid);
+ zfree(&path);
+ }
+
+try_download:
+ /*
+ * We did not match build id or did not find the
+ * binary - try debuginfod as last resort.
+ */
+ if (!path) {
+ bool debuginfo;
+ char *tmp = NULL;
+
+ /*
+ * The debuginfo retrieval for standard binaries
+ * is handled within build_id_cache__add function.
+ *
+ * For kernel and kernel modules we have to ask
+ * for debuginfo directly, because debuginfod
+ * does not treat them as binaries.
+ */
+ debuginfo = is_kallsyms ||
+ is_kernel_module(dso->long_name, PERF_RECORD_MISC_CPUMODE_UNKNOWN);
+
+ if (call_debuginfod(sbuild_id, &tmp, debuginfo)) {
+ err = -1;
+ goto out;
+ }
+
+ path = tmp;
+
+ /*
+ * The kernel dso is now elf binary, so disable is_kallsyms
+ * so build_id_cache__add can prepare proper file names.
+ */
+ is_kallsyms = false;
+ }
+
+ pr_debug("linking %s %s <%s>\n", dso->short_name, path, sbuild_id);
+
+ err = build_id_cache__add(sbuild_id, path, path,
+ dso->nsinfo, is_kallsyms, false);
+out:
+ free(path);
+ fprintf(stderr, "%s %s %s\n", err ? "FAIL" : "OK ", sbuild_id, dso->long_name);
+ return 0;
+}
+
+static int
+build_id_cache__add_perf_data(const char *path, bool all)
+{
+ struct perf_session *session;
+ struct dso_store_data priv = {
+ .hits = !all,
+ };
+ struct perf_data data = {
+ .path = path,
+ .mode = PERF_DATA_MODE_READ,
+ };
+ int err;
+
+ session = perf_session__new(&data, false, &build_id__mark_dso_hit_ops);
+ if (IS_ERR(session))
+ return PTR_ERR(session);
+
+ err = perf_session__process_events(session);
+ if (err)
+ goto out;
+
+ err = __perf_session__cache_build_ids(session, dso_store, &priv);
+out:
+ perf_session__delete(session);
+ return err;
+}
+
int cmd_buildid_cache(int argc, const char **argv)
{
struct strlist *list;
@@ -440,7 +642,15 @@ int cmd_buildid_cache(int argc, const char **argv)
list = strlist__new(add_name_list_str, NULL);
if (list) {
strlist__for_each_entry(pos, list)
- if (build_id_cache__add_file(pos->s, nsi)) {
+ if (is_perf_data(pos->s)) {
+ struct str_node *all_pos = strlist__next(pos);
+ bool all = !strcmp("all", all_pos ? all_pos->s : "");
+
+ if (build_id_cache__add_perf_data(pos->s, all))
+ pr_warning("Couldn't add build ids from %s\n", pos->s);
+ if (all)
+ pos = all_pos;
+ } else if (build_id_cache__add_file(pos->s, nsi)) {
if (errno == EEXIST) {
pr_debug("%s already in the cache\n",
pos->s);
@@ -449,7 +659,6 @@ int cmd_buildid_cache(int argc, const char **argv)
pr_warning("Couldn't add %s: %s\n",
pos->s, str_error_r(errno, sbuf, sizeof(sbuf)));
}
-
strlist__delete(list);
}
}
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index 8eae2afff71a..e821bb977c9b 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1616,9 +1616,9 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
return -EINVAL;
}

- pr_debug("symbol:%s file:%s line:%d offset:%lu return:%d lazy:%s\n",
- pp->function, pp->file, pp->line, pp->offset, pp->retprobe,
- pp->lazy_line);
+ pr_debug2("symbol:%s file:%s line:%d offset:%lu return:%d lazy:%s\n",
+ pp->function, pp->file, pp->line, pp->offset, pp->retprobe,
+ pp->lazy_line);
return 0;
}

--
2.26.2