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Commit d2396999 authored by Krister Johansen's avatar Krister Johansen Committed by Arnaldo Carvalho de Melo
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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: default avatarKrister 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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent f045b8c4

tools/perf/builtin-buildid-cache.c

+1 −1
Original line number Diff line number Diff line
@@ -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)

tools/perf/util/annotate.c

+1 −1
Original line number Diff line number Diff line
@@ -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);

tools/perf/util/build-id.c

+67 −5
Original line number Diff line number Diff line
@@ -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 @@ int build_id_cache__add_s(const char *sbuild_id, const char *name, 
	if (!is_kallsyms)

		free(realname);

	free(filename);

	free(debugfile);

	free(dir_name);

	free(linkname);

	return err;

tools/perf/util/build-id.h

+2 −1
Original line number Diff line number Diff line
@@ -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,

tools/perf/util/dso.c

+7 −1
Original line number Diff line number Diff line
@@ -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;