From 4617721c502b2ddaa4e324e86da4997edf738fa5 Mon Sep 17 00:00:00 2001 From: Steven Rostedt Date: Wed, 2 Sep 2026 09:55:01 -0400 Subject: ftrace: Synchronize the initialization of ftrace_ops There's some internal state that ftrace_ops needs to have set, but since it can be declared outside of the ftrace.c code, it calls ftrace_ops_init() on the ops in every global function. The issue is that if two tasks call it on the same ops at the same time it is possible to have the initialization of one corrupt the initialization of the other call. Create a ops_mutex to use to synchronize every initialization of the ftrace_ops. The mutex is taken within checking the ftrace_ops flag that states it was initializied but the flag is checked again after the mutex has been taken. Checking first outside the mutex allows it to shortcut having to take the mutex. But then the check needs to be done again after the mute is taken in case of races. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260902095501.6b59af20@gandalf.local.home Fixes: f04f24fb7e48d ("ftrace, kprobes: Fix a deadlock on ftrace_regex_lock") Reported-by: sashiko-bot@kernel.org Close: https://lore.kernel.org/all/20260829025528.49A831F000E9@smtp.kernel.org/ Signed-off-by: Steven Rostedt --- tools/perf/tests/symbols.c | 226 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 226 insertions(+) create mode 100644 tools/perf/tests/symbols.c (limited to 'tools/perf/tests/symbols.c') diff --git a/tools/perf/tests/symbols.c b/tools/perf/tests/symbols.c new file mode 100644 index 000000000..c09e04f36 --- /dev/null +++ b/tools/perf/tests/symbols.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 +#include +#include +#include +#include +#include "debug.h" +#include "dso.h" +#include "env.h" +#include "machine.h" +#include "thread.h" +#include "symbol.h" +#include "map.h" +#include "util.h" +#include "tests.h" + +struct test_info { + struct perf_env host_env; + struct machine *machine; + struct thread *thread; +}; + +static int init_test_info(struct test_info *ti) +{ + perf_env__init(&ti->host_env); + ti->machine = machine__new_host(&ti->host_env); + if (!ti->machine) { + pr_debug("machine__new_host() failed!\n"); + perf_env__exit(&ti->host_env); + return TEST_FAIL; + } + + /* Create a dummy thread */ + ti->thread = machine__findnew_thread(ti->machine, 100, 100); + if (!ti->thread) { + pr_debug("machine__findnew_thread() failed!\n"); + perf_env__exit(&ti->host_env); + return TEST_FAIL; + } + + return TEST_OK; +} + +static void exit_test_info(struct test_info *ti) +{ + thread__put(ti->thread); + machine__delete(ti->machine); + perf_env__exit(&ti->host_env); +} + +struct dso_map { + struct dso *dso; + struct map *map; +}; + +static int find_map_cb(struct map *map, void *d) +{ + struct dso_map *data = d; + + if (map__dso(map) != data->dso) + return 0; + data->map = map; + return 1; +} + +static struct map *find_module_map(struct machine *machine, struct dso *dso) +{ + struct dso_map data = { .dso = dso }; + + machine__for_each_kernel_map(machine, find_map_cb, &data); + + return data.map; +} + +static void get_test_dso_filename(char *filename, size_t max_sz) +{ + if (dso_to_test) + strlcpy(filename, dso_to_test, max_sz); + else + perf_exe(filename, max_sz); +} + +static int create_map(struct test_info *ti, char *filename, struct map **map_p) +{ + struct dso *dso = machine__findnew_dso(ti->machine, filename); + + /* + * If 'filename' matches a current kernel module, must use a kernel + * map. Find the one that already exists. + */ + if (dso && dso__kernel(dso) != DSO_SPACE__USER) { + *map_p = find_module_map(ti->machine, dso); + dso__put(dso); + if (!*map_p) { + pr_debug("Failed to find map for current kernel module %s", + filename); + return TEST_FAIL; + } + map__get(*map_p); + return TEST_OK; + } + + dso__put(dso); + + /* Create a dummy map at 0x100000 */ + *map_p = map__new(ti->machine, 0x100000, 0xffffffff, 0, &dso_id_empty, + PROT_EXEC, /*flags=*/0, filename, ti->thread); + if (!*map_p) { + pr_debug("Failed to create map!"); + return TEST_FAIL; + } + + return TEST_OK; +} + +static int test_dso(struct dso *dso) +{ + struct symbol *last_sym = NULL; + struct rb_node *nd; + int ret = TEST_OK; + + /* dso__fprintf() prints all the symbols */ + if (verbose > 1) + dso__fprintf(dso, stderr); + + for (nd = rb_first_cached(dso__symbols(dso)); nd; nd = rb_next(nd)) { + struct symbol *sym = rb_entry(nd, struct symbol, rb_node); + + if (symbol__type(sym) != STT_FUNC && symbol__type(sym) != STT_GNU_IFUNC) + continue; + + /* Check for overlapping function symbols */ + if (last_sym && sym->start < last_sym->end) { + pr_debug("Overlapping symbols:\n"); + symbol__fprintf(last_sym, stderr); + symbol__fprintf(sym, stderr); + ret = TEST_FAIL; + } + /* Check for zero-length function symbol */ + if (sym->start == sym->end) { + pr_debug("Zero-length symbol:\n"); + symbol__fprintf(sym, stderr); + ret = TEST_FAIL; + } + last_sym = sym; + } + + return ret; +} + +static int subdivided_dso_cb(struct dso *dso, struct machine *machine __maybe_unused, void *d) +{ + struct dso *text_dso = d; + + if (dso != text_dso && strstarts(dso__short_name(dso), dso__short_name(text_dso))) + if (test_dso(dso) != TEST_OK) + return -1; + + return 0; +} + +static int process_subdivided_dso(struct machine *machine, struct dso *dso) +{ + int ret; + + ret = machine__for_each_dso(machine, subdivided_dso_cb, dso); + + return ret < 0 ? TEST_FAIL : TEST_OK; +} + +static int test_file(struct test_info *ti, char *filename) +{ + struct map *map = NULL; + int ret, nr; + struct dso *dso; + + pr_debug("Testing %s\n", filename); + + ret = create_map(ti, filename, &map); + if (ret != TEST_OK) + return ret; + + dso = map__dso(map); + nr = dso__load(dso, map); + if (nr < 0) { + pr_debug("dso__load() failed!\n"); + ret = TEST_FAIL; + goto out_put; + } + + if (nr == 0) { + pr_debug("DSO has no symbols!\n"); + ret = TEST_SKIP; + goto out_put; + } + + ret = test_dso(dso); + + /* Module dso is split into many dsos by section */ + if (ret == TEST_OK && dso__kernel(dso) != DSO_SPACE__USER) + ret = process_subdivided_dso(ti->machine, dso); +out_put: + map__put(map); + + return ret; +} + +static int test__symbols(struct test_suite *test __maybe_unused, int subtest __maybe_unused) +{ + char filename[PATH_MAX]; + struct test_info ti; + int ret; + + ret = init_test_info(&ti); + if (ret != TEST_OK) + return ret; + + get_test_dso_filename(filename, sizeof(filename)); + + ret = test_file(&ti, filename); + + exit_test_info(&ti); + + return ret; +} + +DEFINE_SUITE("Symbols", symbols); -- cgit v1.3.1