perf buildid-cache: Cache debuginfo

If a stripped binary is placed in the cache, the user is in a situation
where there's a cached elf file present, but it doesn't have any symtab
to use for name resolution.  Grab the debuginfo for binaries that don't
end in .ko.  This yields a better chance of resolving symbols from older
traces.

Signed-off-by: Krister Johansen <kjlx@templeofstupid.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas-Mich Richter <tmricht@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1499305693-1599-7-git-send-email-kjlx@templeofstupid.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c
index d65bd86bee991938023db778a27c119a92721309..e3eb6240ced0903799d3add8998111dab488205a 100644 (file)
--- a/tools/perf/builtin-buildid-cache.c
+++ b/tools/perf/builtin-buildid-cache.c
@@ -243,7 +243,7 @@ static bool dso__missing_buildid_cache(struct dso *dso, int parm __maybe_unused)
        char filename[PATH_MAX];
        u8 build_id[BUILD_ID_SIZE];
 
-       if (dso__build_id_filename(dso, filename, sizeof(filename)) &&
+       if (dso__build_id_filename(dso, filename, sizeof(filename), false) &&
            filename__read_build_id(filename, build_id,
                                    sizeof(build_id)) != sizeof(build_id)) {
                if (errno == ENOENT)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index ef434b53d849060eaf3d6c4e9b850a64439500b1..1742510f01200b060d55c7322a8574c2dbc69764 100644 (file)
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1347,7 +1347,7 @@ static int dso__disassemble_filename(struct dso *dso, char *filename, size_t fil
            !dso__is_kcore(dso))
                return SYMBOL_ANNOTATE_ERRNO__NO_VMLINUX;
 
-       build_id_filename = dso__build_id_filename(dso, NULL, 0);
+       build_id_filename = dso__build_id_filename(dso, NULL, 0, false);
        if (build_id_filename) {
                __symbol__join_symfs(filename, filename_size, build_id_filename);
                free(build_id_filename);

diff --git a/tools/perf/util/build-id.c b/tools/perf/util/build-id.c
index f7bfd90a7388e28447fb10115042088aa80237b4..e9665150e9b17b20f865247bfa3a45d81cb4b696 100644 (file)
--- a/tools/perf/util/build-id.c
+++ b/tools/perf/util/build-id.c
@@ -243,12 +243,15 @@ static bool build_id_cache__valid_id(char *sbuild_id)
        return result;
 }
 
-static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso)
+static const char *build_id_cache__basename(bool is_kallsyms, bool is_vdso,
+                                           bool is_debug)
 {
-       return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : "elf");
+       return is_kallsyms ? "kallsyms" : (is_vdso ? "vdso" : (is_debug ?
+           "debug" : "elf"));
 }
 
-char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
+char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
+                            bool is_debug)
 {
        bool is_kallsyms = dso__is_kallsyms((struct dso *)dso);
        bool is_vdso = dso__is_vdso((struct dso *)dso);
@@ -270,7 +273,8 @@ char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size)
                ret = asnprintf(&bf, size, "%s", linkname);
        else
                ret = asnprintf(&bf, size, "%s/%s", linkname,
-                        build_id_cache__basename(is_kallsyms, is_vdso));
+                        build_id_cache__basename(is_kallsyms, is_vdso,
+                                                 is_debug));
        if (ret < 0 || (!alloc && size < (unsigned int)ret))
                bf = NULL;
        free(linkname);
@@ -603,12 +607,40 @@ static int build_id_cache__add_sdt_cache(const char *sbuild_id,
 #define build_id_cache__add_sdt_cache(sbuild_id, realname, nsi) (0)
 #endif
 
+static char *build_id_cache__find_debug(const char *sbuild_id,
+                                       struct nsinfo *nsi)
+{
+       char *realname = NULL;
+       char *debugfile;
+       struct nscookie nsc;
+       size_t len = 0;
+
+       debugfile = calloc(1, PATH_MAX);
+       if (!debugfile)
+               goto out;
+
+       len = __symbol__join_symfs(debugfile, PATH_MAX,
+                                  "/usr/lib/debug/.build-id/");
+       snprintf(debugfile + len, PATH_MAX - len, "%.2s/%s.debug", sbuild_id,
+                sbuild_id + 2);
+
+       nsinfo__mountns_enter(nsi, &nsc);
+       realname = realpath(debugfile, NULL);
+       if (realname && access(realname, R_OK))
+               zfree(&realname);
+       nsinfo__mountns_exit(&nsc);
+out:
+       free(debugfile);
+       return realname;
+}
+
 int build_id_cache__add_s(const char *sbuild_id, const char *name,
                          struct nsinfo *nsi, bool is_kallsyms, bool is_vdso)
 {
        const size_t size = PATH_MAX;
        char *realname = NULL, *filename = NULL, *dir_name = NULL,
             *linkname = zalloc(size), *tmp;
+       char *debugfile = NULL;
        int err = -1;
 
        if (!is_kallsyms) {
@@ -635,7 +667,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
 
        /* Save the allocated buildid dirname */
        if (asprintf(&filename, "%s/%s", dir_name,
-                    build_id_cache__basename(is_kallsyms, is_vdso)) < 0) {
+                    build_id_cache__basename(is_kallsyms, is_vdso,
+                    false)) < 0) {
                filename = NULL;
                goto out_free;
        }
@@ -652,6 +685,34 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name,
                        goto out_free;
        }
 
+       /* Some binaries are stripped, but have .debug files with their symbol
+        * table.  Check to see if we can locate one of those, since the elf
+        * file itself may not be very useful to users of our tools without a
+        * symtab.
+        */
+       if (!is_kallsyms && !is_vdso &&
+           strncmp(".ko", name + strlen(name) - 3, 3)) {
+               debugfile = build_id_cache__find_debug(sbuild_id, nsi);
+               if (debugfile) {
+                       zfree(&filename);
+                       if (asprintf(&filename, "%s/%s", dir_name,
+                           build_id_cache__basename(false, false, true)) < 0) {
+                               filename = NULL;
+                               goto out_free;
+                       }
+                       if (access(filename, F_OK)) {
+                               if (nsi && nsi->need_setns) {
+                                       if (copyfile_ns(debugfile, filename,
+                                                       nsi))
+                                               goto out_free;
+                               } else if (link(debugfile, filename) &&
+                                               errno != EEXIST &&
+                                               copyfile(debugfile, filename))
+                                       goto out_free;
+                       }
+               }
+       }
+
        if (!build_id_cache__linkname(sbuild_id, linkname, size))
                goto out_free;
        tmp = strrchr(linkname, '/');
@@ -676,6 +737,7 @@ out_free:
        if (!is_kallsyms)
                free(realname);
        free(filename);
+       free(debugfile);
        free(dir_name);
        free(linkname);
        return err;

diff --git a/tools/perf/util/build-id.h b/tools/perf/util/build-id.h
index 23970847d4c44e8123eb08a9ede013f40814cf71..113dc0615c574dc521de69d6a459b5579751a1d1 100644 (file)
--- a/tools/perf/util/build-id.h
+++ b/tools/perf/util/build-id.h
@@ -17,7 +17,8 @@ int filename__sprintf_build_id(const char *pathname, char *sbuild_id);
 char *build_id_cache__kallsyms_path(const char *sbuild_id, char *bf,
                                    size_t size);
 
-char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size);
+char *dso__build_id_filename(const struct dso *dso, char *bf, size_t size,
+                            bool is_debug);
 
 int build_id__mark_dso_hit(struct perf_tool *tool, union perf_event *event,
                           struct perf_sample *sample, struct perf_evsel *evsel,

diff --git a/tools/perf/util/dso.c b/tools/perf/util/dso.c
index dc9b49533a8f531837bf07b21ee89995ca72356a..b9e087fb8247983f0f3aed7e984dc5eb2615de7c 100644 (file)
--- a/tools/perf/util/dso.c
+++ b/tools/perf/util/dso.c
@@ -32,6 +32,7 @@ char dso__symtab_origin(const struct dso *dso)
                [DSO_BINARY_TYPE__JAVA_JIT]                     = 'j',
                [DSO_BINARY_TYPE__DEBUGLINK]                    = 'l',
                [DSO_BINARY_TYPE__BUILD_ID_CACHE]               = 'B',
+               [DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO]     = 'D',
                [DSO_BINARY_TYPE__FEDORA_DEBUGINFO]             = 'f',
                [DSO_BINARY_TYPE__UBUNTU_DEBUGINFO]             = 'u',
                [DSO_BINARY_TYPE__OPENEMBEDDED_DEBUGINFO]       = 'o',
@@ -97,7 +98,12 @@ int dso__read_binary_type_filename(const struct dso *dso,
                break;
        }
        case DSO_BINARY_TYPE__BUILD_ID_CACHE:
-               if (dso__build_id_filename(dso, filename, size) == NULL)
+               if (dso__build_id_filename(dso, filename, size, false) == NULL)
+                       ret = -1;
+               break;
+
+       case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
+               if (dso__build_id_filename(dso, filename, size, true) == NULL)
                        ret = -1;
                break;
 

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 78ec637fc68b29b06fab8c3e2a23f07bb59a1eb9..f886141678ebaf816290fc4ca274e6ef10d6525b 100644 (file)
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -21,6 +21,7 @@ enum dso_binary_type {
        DSO_BINARY_TYPE__JAVA_JIT,
        DSO_BINARY_TYPE__DEBUGLINK,
        DSO_BINARY_TYPE__BUILD_ID_CACHE,
+       DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO,
        DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
        DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
        DSO_BINARY_TYPE__BUILDID_DEBUGINFO,

diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c
index 246b441110a1749e9a6566701bb60800f43a15c7..a54a2be5eda49bf48cfdf7abd511f58be90a5c3b 100644 (file)
--- a/tools/perf/util/machine.c
+++ b/tools/perf/util/machine.c
@@ -705,7 +705,8 @@ size_t machine__fprintf_vmlinux_path(struct machine *machine, FILE *fp)
 
        if (kdso->has_build_id) {
                char filename[PATH_MAX];
-               if (dso__build_id_filename(kdso, filename, sizeof(filename)))
+               if (dso__build_id_filename(kdso, filename, sizeof(filename),
+                                          false))
                        printed += fprintf(fp, "[0] %s\n", filename);
        }
 

diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 8c7bae5456179386cb6006e841b0193bc0663b4f..971b990557b4565bbf83cc4ad4a7b4366005dcef 100644 (file)
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -53,6 +53,7 @@ static enum dso_binary_type binary_type_symtab[] = {
        DSO_BINARY_TYPE__JAVA_JIT,
        DSO_BINARY_TYPE__DEBUGLINK,
        DSO_BINARY_TYPE__BUILD_ID_CACHE,
+       DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO,
        DSO_BINARY_TYPE__FEDORA_DEBUGINFO,
        DSO_BINARY_TYPE__UBUNTU_DEBUGINFO,
        DSO_BINARY_TYPE__BUILDID_DEBUGINFO,
@@ -1418,6 +1419,7 @@ static bool dso__is_compatible_symtab_type(struct dso *dso, bool kmod,
                return kmod && dso->symtab_type == type;
 
        case DSO_BINARY_TYPE__BUILD_ID_CACHE:
+       case DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO:
                return true;
 
        case DSO_BINARY_TYPE__NOT_FOUND:
@@ -1565,10 +1567,14 @@ int dso__load(struct dso *dso, struct map *map)
                struct symsrc *ss = &ss_[ss_pos];
                bool next_slot = false;
                bool is_reg;
+               bool nsexit;
                int sirc;
 
                enum dso_binary_type symtab_type = binary_type_symtab[i];
 
+               nsexit = (symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE ||
+                   symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE_DEBUGINFO);
+
                if (!dso__is_compatible_symtab_type(dso, kmod, symtab_type))
                        continue;
 
@@ -1576,13 +1582,13 @@ int dso__load(struct dso *dso, struct map *map)
                                                   root_dir, name, PATH_MAX))
                        continue;
 
-               if (symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
+               if (nsexit)
                        nsinfo__mountns_exit(&nsc);
 
                is_reg = is_regular_file(name);
                sirc = symsrc__init(ss, dso, name, symtab_type);
 
-               if (symtab_type == DSO_BINARY_TYPE__BUILD_ID_CACHE)
+               if (nsexit)
                        nsinfo__mountns_enter(dso->nsinfo, &nsc);
 
                if (!is_reg || sirc < 0) {
@@ -1724,7 +1730,7 @@ int dso__load_vmlinux_path(struct dso *dso, struct map *map)
        }
 
        if (!symbol_conf.ignore_vmlinux_buildid)
-               filename = dso__build_id_filename(dso, NULL, 0);
+               filename = dso__build_id_filename(dso, NULL, 0, false);
        if (filename != NULL) {
                err = dso__load_vmlinux(dso, map, filename, true);
                if (err > 0)