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Message-ID: <CAM9d7ch5Od3Pz6GORmkW6RfUQL6ON0DVJ+dndA9mGCv6ppLsbA@mail.gmail.com>
Date: Mon, 14 Sep 2020 15:42:55 +0900
From: Namhyung Kim <namhyung@...nel.org>
To: Jiri Olsa <jolsa@...nel.org>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
lkml <linux-kernel@...r.kernel.org>,
Peter Zijlstra <a.p.zijlstra@...llo.nl>,
Ingo Molnar <mingo@...nel.org>,
Mark Rutland <mark.rutland@....com>,
Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Michael Petlan <mpetlan@...hat.com>,
Song Liu <songliubraving@...com>,
"Frank Ch. Eigler" <fche@...hat.com>,
Ian Rogers <irogers@...gle.com>,
Stephane Eranian <eranian@...gle.com>,
Alexey Budankov <alexey.budankov@...ux.intel.com>,
Andi Kleen <ak@...ux.intel.com>,
Adrian Hunter <adrian.hunter@...el.com>
Subject: Re: [PATCH 24/26] perf tools: Add buildid-list --store option
On Mon, Sep 14, 2020 at 6:05 AM Jiri Olsa <jolsa@...nel.org> wrote:
>
> Adding buildid-list --store option to populate
> .debug data with build id files.
Hmm.. isn't it better to add it to the buildid-cache command?
>
> $ rm -rf ~/.debug/
>
> $ perf buildid-list
> 1805c738c8f3ec0f47b7ea09080c28f34d18a82b /usr/lib64/ld-2.31.so
> d278249792061c6b74d1693ca59513be1def13f2 /usr/lib64/libc-2.31.so
>
> $ perf buildid-list --store
>
> $ find ~/.debug/
> .../.debug/
> .../.debug/usr
> .../.debug/usr/lib64
> .../.debug/usr/lib64/ld-2.31.so
> .../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b
> .../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/elf
> .../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/debug
> .../.debug/usr/lib64/ld-2.31.so/1805c738c8f3ec0f47b7ea09080c28f34d18a82b/probes
> .../.debug/usr/lib64/libc-2.31.so
> .../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2
> .../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/elf
> .../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/debug
> .../.debug/usr/lib64/libc-2.31.so/d278249792061c6b74d1693ca59513be1def13f2/probes
> .../.debug/.build-id
> .../.debug/.build-id/18
> .../.debug/.build-id/18/05c738c8f3ec0f47b7ea09080c28f34d18a82b
> .../.debug/.build-id/d2
> .../.debug/.build-id/d2/78249792061c6b74d1693ca59513be1def13f2
>
> It's possible to query debuginfod daemon for binaries by defining
> DEBUGINFOD_URLS variable with server URL, like:
>
> $ DEBUGINFOD_URLS=http://192.168.122.174:8002 perf buildid-list --store
> OK 439fe9bdeaed66af2bb8b8de5e650d5ecc3d8d46 .../.debug/.build-id/43/9fe9bdeaed66af2bb8b8de5e650d5ecc3d8d46/elf
> FAIL 23b87f5b0560481043257e82be670bc97786a171 /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/net/ipv4/netfilter/ip_tables.ko.xz
> FAIL d2b3be372bcdd4ebc15e479d2ff803657de0fd1e /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/drivers/block/virtio_blk.ko.xz
> FAIL 1466a71bcd0ff5c975ee79b72752137c0143d225 /lib/modules/5.9.0-0.rc3.1.mmap3.fc34.x86_64/kernel/fs/xfs/xfs.ko.xz
> OK ad60d10b38c93bd8738d5aa594e240f01bb328cd /usr/lib/systemd/systemd
> OK 589e403a34f55486bcac848a45e00bcdeedd1ca8 /usr/lib64/libcrypto.so.1.1.1g
> OK 3b9b2ef537520303411ad5038b596d5d18e7c2b8 /usr/lib64/libpcre2-8.so.0.10.0
>
> Increasing debug level in util/probe-event.c to get rid
> of the sdt probes messages on single verbose level (-v).
>
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
[SNIP]
> +static int dso__store(struct dso *dso, struct machine *machine __maybe_unused, void *priv)
> +{
> + struct dso_store_data *data = priv;
> + char sbuild_id[SBUILD_ID_SIZE];
> + u8 bid[BUILD_ID_SIZE];
> + char *path = NULL;
> + bool is_kallsyms;
> + int err = -1;
> +
> + if (!dso->has_build_id ||
> + !build_id__is_defined(dso->build_id))
> + return 0;
> +
> + if (data->with_hits && !dso->hit)
> + return 0;
> +
> + /*
> + * The storing process is:
> + * - get build id of the dso
> + * - check if it matches provided build id from mmap3 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->build_id, sizeof(dso->build_id), sbuild_id);
> +
> + if (is_kallsyms) {
> + /*
> + * Find out if we are on the same kernel as perf.data
> + * and keel kallsyms in that case.
> + */
> + path = strdup(dso->long_name);
> + if (!path)
> + goto out_err;
> +
> + err = sysfs__read_build_id("/sys/kernel/notes", &bid, sizeof(bid));
> + if (err < 0)
> + goto out_err;
> + } else {
> + struct stat st;
> +
> + /*
> + * Does the file exists in the first place, if it does,
> + * resolve path and read the build id.
> + */
> + if (stat(dso->long_name, &st)) {
> + zfree(&path);
> + goto try_download;
> + }
> +
> + path = nsinfo__realpath(dso->long_name, dso->nsinfo);
> + if (!path)
> + goto out_err;
> +
> + err = filename__read_build_id(path, &bid, sizeof(bid));
Is it ok to read the file out of the namespace?
Thanks
Namhyung
> + if (err != sizeof(bid))
> + goto out_err;
> + }
> +
> + /*
> + * If we match then we want in mmap3 event,
> + * is what we got in the binary, so we're happy.
> + */
> + if (memcmp(&bid, dso->build_id, BUILD_ID_SIZE)) {
> + char sbid[SBUILD_ID_SIZE];
> +
> + build_id__sprintf(bid, sizeof(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) {
> + char *tmp = NULL;
> +
> + /*
> + * The debuginfo retrieval is handled within
> + * build_id_cache__add function.
> + */
> + if (get_executable(sbuild_id, &tmp)) {
> + err = -1;
> + goto out_err;
> + }
> +
> + 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_err:
> + free(path);
> + fprintf(stderr, "%s %s %s\n", err ? "FAIL" : "OK ", sbuild_id, dso->long_name);
> + return 0;
> +}
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