perf machine: Propagate machine__init() error to callers

machine__init() always returns 0 even when memory allocation fails,
because commit 81f981d7ec ("perf machine: Free root_dir in
machine__init() error path") introduced 'int err = -ENOMEM' and an
error cleanup path but left the final 'return 0' instead of
'return err'.

Fix by returning err, check the return value in __machine__new_host()
which was ignoring it, and change machines__init() from void to int so
it too can propagate the error to perf_session__new(), aslr_tool__init()
and test callers.

The error cleanup also used zfree(&machine->kmaps), but kmaps is a
refcounted maps structure — use maps__zput() to properly drop the
reference, matching machine__exit().

Move dsos__init() and threads__init() before the first fallible
allocation (maps__new) so that machine__exit() is safe to call on
any machine struct that machine__init() touched, even on early failure.

Fixes: 81f981d7ec ("perf machine: Free root_dir in machine__init() error path")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/tests/hists_cumulate.c

@@ -704,7 +704,7 @@ static int test4(struct evsel *evsel, struct machine *machine)
 static int test__hists_cumulate(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {
 	int err = TEST_FAIL;
-	struct machines machines;
+	struct machines machines = { 0 };
 	struct machine *machine;
 	struct evsel *evsel;
 	struct evlist *evlist = evlist__new();
@@ -723,7 +723,8 @@ static int test__hists_cumulate(struct test_suite *test __maybe_unused, int subt
 		goto out;
 	err = TEST_FAIL;
 
-	machines__init(&machines);
+	if (machines__init(&machines))
+		goto out;
 
 	/* setup threads/dso/map/symbols also */
 	machine = setup_fake_machine(&machines);

tools/perf/tests/hists_filter.c

@@ -116,7 +116,7 @@ static void put_fake_samples(void)
 static int test__hists_filter(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {
 	int err = TEST_FAIL;
-	struct machines machines;
+	struct machines machines = { 0 };
 	struct machine *machine;
 	struct evsel *evsel;
 	struct evlist *evlist = evlist__new();
@@ -131,7 +131,8 @@ static int test__hists_filter(struct test_suite *test __maybe_unused, int subtes
 		goto out;
 	err = TEST_FAIL;
 
-	machines__init(&machines);
+	if (machines__init(&machines))
+		goto out;
 
 	/* setup threads/dso/map/symbols also */
 	machine = setup_fake_machine(&machines);

tools/perf/tests/hists_link.c

@@ -287,7 +287,7 @@ static int test__hists_link(struct test_suite *test __maybe_unused, int subtest
 {
 	int err = -1;
 	struct hists *hists, *first_hists;
-	struct machines machines;
+	struct machines machines = { 0 };
 	struct machine *machine = NULL;
 	struct evsel *evsel, *first;
 	struct evlist *evlist = evlist__new();
@@ -303,7 +303,8 @@ static int test__hists_link(struct test_suite *test __maybe_unused, int subtest
 		goto out;
 
 	err = TEST_FAIL;
-	machines__init(&machines);
+	if (machines__init(&machines))
+		goto out;
 
 	/* setup threads/dso/map/symbols also */
 	machine = setup_fake_machine(&machines);

tools/perf/tests/hists_output.c

@@ -590,7 +590,7 @@ static int test5(struct evsel *evsel, struct machine *machine)
 static int test__hists_output(struct test_suite *test __maybe_unused, int subtest __maybe_unused)
 {
 	int err = TEST_FAIL;
-	struct machines machines;
+	struct machines machines = { 0 };
 	struct machine *machine;
 	struct evsel *evsel;
 	struct evlist *evlist = evlist__new();
@@ -610,7 +610,8 @@ static int test__hists_output(struct test_suite *test __maybe_unused, int subtes
 		goto out;
 	err = TEST_FAIL;
 
-	machines__init(&machines);
+	if (machines__init(&machines))
+		goto out;
 
 	/* setup threads/dso/map/symbols also */
 	machine = setup_fake_machine(&machines);

tools/perf/tests/kallsyms-split.c

@@ -97,7 +97,7 @@ static int create_proc_dir(void)
 static int test__kallsyms_split(struct test_suite *test __maybe_unused,
 				int subtest __maybe_unused)
 {
-	struct machine m;
+	struct machine m = { 0 };
 	struct map *map = NULL;
 	int ret = TEST_FAIL;
 
@@ -113,7 +113,10 @@ static int test__kallsyms_split(struct test_suite *test __maybe_unused,
 	signal(SIGTERM, remove_proc_dir);
 
 	pr_debug("create kernel maps from the fake root directory\n");
-	machine__init(&m, root_dir, HOST_KERNEL_ID);
+	if (machine__init(&m, root_dir, HOST_KERNEL_ID)) {
+		pr_debug("FAIL: failed to init machine\n");
+		goto out;
+	}
 	if (machine__create_kernel_maps(&m) < 0) {
 		pr_debug("FAIL: failed to create kernel maps\n");
 		goto out;

tools/perf/tests/thread-maps-share.c

@@ -27,7 +27,7 @@ static int test__thread_maps_share(struct test_suite *test __maybe_unused, int s
 	 * other  group (pid: 4, tids: 4, 5)
 	*/
 
-	machines__init(&machines);
+	TEST_ASSERT_VAL("failed to init machines", machines__init(&machines) == 0);
 	machine = &machines.host;
 
 	/* create process with 4 threads */

tools/perf/tests/vmlinux-kallsyms.c

@@ -192,7 +192,7 @@ static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused
 	struct rb_node *nd;
 	struct symbol *sym;
 	struct map *kallsyms_map;
-	struct machine vmlinux;
+	struct machine vmlinux = { 0 };
 	struct maps *maps;
 	u64 mem_start, mem_end;
 	struct test__vmlinux_matches_kallsyms_cb_args args;
@@ -203,8 +203,10 @@ static int test__vmlinux_matches_kallsyms(struct test_suite *test __maybe_unused
 	 * Init the machines that will hold kernel, modules obtained from
 	 * both vmlinux + .ko files and from /proc/kallsyms split by modules.
 	 */
-	machine__init(&args.kallsyms, "", HOST_KERNEL_ID);
-	machine__init(&vmlinux, "", HOST_KERNEL_ID);
+	if (machine__init(&args.kallsyms, "", HOST_KERNEL_ID))
+		goto out;
+	if (machine__init(&vmlinux, "", HOST_KERNEL_ID))
+		goto out;
 
 	maps = machine__kernel_maps(&vmlinux);
 

tools/perf/util/aslr.c

@@ -1237,12 +1237,13 @@ void aslr_tool__strip_attr_event(union perf_event *event, struct evlist *evlist)
 	}
 }
 
-static void aslr_tool__init(struct aslr_tool *aslr, struct perf_tool *delegate)
+static int aslr_tool__init(struct aslr_tool *aslr, struct perf_tool *delegate)
 {
 	delegate_tool__init(&aslr->tool, delegate);
 	aslr->tool.tool.ordered_events = true;
 
-	machines__init(&aslr->machines);
+	if (machines__init(&aslr->machines))
+		return -ENOMEM;
 
 	hashmap__init(&aslr->remap_addresses,
 		      remap_addresses__hash, remap_addresses__equal,
@@ -1276,6 +1277,8 @@ static void aslr_tool__init(struct aslr_tool *aslr, struct perf_tool *delegate)
 	aslr->tool.tool.auxtrace = aslr_tool__process_auxtrace;
 	aslr->tool.tool.auxtrace_info = aslr_tool__process_auxtrace_info;
 	aslr->tool.tool.auxtrace_error = aslr_tool__process_auxtrace_error;
+
+	return 0;
 }
 
 struct perf_tool *aslr_tool__new(struct perf_tool *delegate)
@@ -1285,7 +1288,10 @@ struct perf_tool *aslr_tool__new(struct perf_tool *delegate)
 	if (!aslr)
 		return NULL;
 
-	aslr_tool__init(aslr, delegate);
+	if (aslr_tool__init(aslr, delegate)) {
+		free(aslr);
+		return NULL;
+	}
 	return &aslr->tool.tool;
 }
 

tools/perf/util/machine.c

@@ -79,15 +79,14 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 	int err = -ENOMEM;
 
 	memset(machine, 0, sizeof(*machine));
-	machine->kmaps = maps__new(machine);
-	if (machine->kmaps == NULL)
-		return -ENOMEM;
-
 	RB_CLEAR_NODE(&machine->rb_node);
 	dsos__init(&machine->dsos);
-
 	threads__init(&machine->threads);
 
+	machine->kmaps = maps__new(machine);
+	if (machine->kmaps == NULL)
+		goto out;
+
 	machine->vdso_info = NULL;
 	machine->env = NULL;
 
@@ -124,11 +123,11 @@ int machine__init(struct machine *machine, const char *root_dir, pid_t pid)
 
 out:
 	if (err) {
-		zfree(&machine->kmaps);
+		maps__zput(machine->kmaps);
 		zfree(&machine->root_dir);
 		zfree(&machine->mmap_name);
 	}
-	return 0;
+	return err;
 }
 
 static struct machine *__machine__new_host(struct perf_env *host_env, bool kernel_maps)
@@ -138,7 +137,10 @@ static struct machine *__machine__new_host(struct perf_env *host_env, bool kerne
 	if (!machine)
 		return NULL;
 
-	machine__init(machine, "", HOST_KERNEL_ID);
+	if (machine__init(machine, "", HOST_KERNEL_ID) != 0) {
+		free(machine);
+		return NULL;
+	}
 
 	if (kernel_maps && machine__create_kernel_maps(machine) < 0) {
 		free(machine);
@@ -231,10 +233,12 @@ void machine__delete(struct machine *machine)
 	}
 }
 
-void machines__init(struct machines *machines)
+int machines__init(struct machines *machines)
 {
-	machine__init(&machines->host, "", HOST_KERNEL_ID);
+	int err = machine__init(&machines->host, "", HOST_KERNEL_ID);
+
 	machines->guests = RB_ROOT_CACHED;
+	return err;
 }
 
 void machines__exit(struct machines *machines)

tools/perf/util/machine.h

@@ -152,7 +152,7 @@ struct machines {
 	struct rb_root_cached guests;
 };
 
-void machines__init(struct machines *machines);
+int machines__init(struct machines *machines);
 void machines__exit(struct machines *machines);
 
 void machines__process_guests(struct machines *machines,

tools/perf/util/session.c

@@ -160,11 +160,12 @@ struct perf_session *__perf_session__new(struct perf_data *data,
 	session->decomp_data.zstd_decomp = &session->zstd_data;
 	session->active_decomp = &session->decomp_data;
 	INIT_LIST_HEAD(&session->auxtrace_index);
-	machines__init(&session->machines);
+	perf_env__init(&session->header.env);
+	if (machines__init(&session->machines))
+		goto out_delete;
+
 	ordered_events__init(&session->ordered_events,
 			     ordered_events__deliver_event, NULL);
-
-	perf_env__init(&session->header.env);
 	if (data) {
 		ret = perf_data__open(data);
 		if (ret < 0)