On Thu, May 15, 2025 at 5:15 AM Jiri Olsa <jo...@kernel.org> wrote: > > Adding test that makes sure parallel execution of the uprobe and > attach/detach of optimized uprobe on it works properly. > > Signed-off-by: Jiri Olsa <jo...@kernel.org> > --- > .../selftests/bpf/prog_tests/uprobe_syscall.c | 94 +++++++++++++++++++ > 1 file changed, 94 insertions(+) > > diff --git a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c > b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c > index b9152ca8cdf5..a83abbe91b01 100644 > --- a/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c > +++ b/tools/testing/selftests/bpf/prog_tests/uprobe_syscall.c > @@ -15,6 +15,7 @@ > #include <asm/prctl.h> > #include "uprobe_syscall.skel.h" > #include "uprobe_syscall_executed.skel.h" > +#include "bpf/libbpf_internal.h" > > #define USDT_NOP .byte 0x0f, 0x1f, 0x44, 0x00, 0x00 > #include "usdt.h" > @@ -634,6 +635,97 @@ static void test_uretprobe_shadow_stack(void) > ARCH_PRCTL(ARCH_SHSTK_DISABLE, ARCH_SHSTK_SHSTK); > } > > +static volatile bool race_stop; > + > +static USDT_DEFINE_SEMA(race); > + > +static void *worker_trigger(void *arg) > +{ > + unsigned long rounds = 0; > + > + while (!race_stop) { > + uprobe_test(); > + rounds++; > + } > + > + printf("tid %d trigger rounds: %lu\n", gettid(), rounds); > + return NULL; > +} > + > +static void *worker_attach(void *arg) > +{ > + LIBBPF_OPTS(bpf_uprobe_opts, opts); > + struct uprobe_syscall_executed *skel; > + unsigned long rounds = 0, offset; > + const char *sema[2] = { > + __stringify(USDT_SEMA(race)), > + NULL, > + }; > + unsigned long *ref; > + int err; > + > + offset = get_uprobe_offset(&uprobe_test); > + if (!ASSERT_GE(offset, 0, "get_uprobe_offset")) > + return NULL; > + > + err = elf_resolve_syms_offsets("/proc/self/exe", 1, (const char **) > &sema, &ref, STT_OBJECT); > + if (!ASSERT_OK(err, "elf_resolve_syms_offsets_sema")) > + return NULL; > + > + opts.ref_ctr_offset = *ref; > + > + skel = uprobe_syscall_executed__open_and_load(); > + if (!ASSERT_OK_PTR(skel, "uprobe_syscall_executed__open_and_load")) > + return NULL; > + > + while (!race_stop) { > + skel->links.test_uprobe = > bpf_program__attach_uprobe_opts(skel->progs.test_uprobe, > + 0, "/proc/self/exe", offset, &opts); > + if (!ASSERT_OK_PTR(skel->links.test_uprobe, > "bpf_program__attach_uprobe_opts")) > + break; > + > + bpf_link__destroy(skel->links.test_uprobe); > + skel->links.test_uprobe = NULL; > + rounds++; > + } > + > + printf("tid %d attach rounds: %lu hits: %d\n", gettid(), rounds, > skel->bss->executed); > + uprobe_syscall_executed__destroy(skel); > + free(ref); > + return NULL; > +} > + > +static void test_uprobe_race(void) > +{ > + int err, i, nr_threads; > + pthread_t *threads; > + > + nr_threads = libbpf_num_possible_cpus(); > + if (!ASSERT_GT(nr_threads, 0, "libbpf_num_possible_cpus")) > + return; > + nr_threads = max(2, nr_threads); > + > + threads = malloc(sizeof(*threads) * nr_threads);
leaking this? maybe just use `pthread_t thread[nr_threads];`? or alloca()? > + if (!ASSERT_OK_PTR(threads, "malloc")) > + return; > + > + for (i = 0; i < nr_threads; i++) { > + err = pthread_create(&threads[i], NULL, i % 2 ? > worker_trigger : worker_attach, > + NULL); > + if (!ASSERT_OK(err, "pthread_create")) > + goto cleanup; > + } > + > + sleep(4); 4 seconds... can we make it much shorter and allow to define the actual runtime with envvar? So for thorough testing you'll define something multi-second, but once things land and settle we can run it for 100ms at most and not slow down CI significantly? All these slow tests do add up :( > + > +cleanup: > + race_stop = true; > + for (nr_threads = i, i = 0; i < nr_threads; i++) > + pthread_join(threads[i], NULL); > + > + ASSERT_FALSE(USDT_SEMA_IS_ACTIVE(race), "race_semaphore"); > +} > + > static void __test_uprobe_syscall(void) > { > if (test__start_subtest("uretprobe_regs_equal")) > @@ -652,6 +744,8 @@ static void __test_uprobe_syscall(void) > test_uprobe_session(); > if (test__start_subtest("uprobe_usdt")) > test_uprobe_usdt(); > + if (test__start_subtest("uprobe_race")) > + test_uprobe_race(); > } > #else > static void __test_uprobe_syscall(void) > -- > 2.49.0 >