From 60b1af8de8c17f0edc86dc55c0bea9be3bb41626 Mon Sep 17 00:00:00 2001 From: Beau Belgrave Date: Tue, 28 Mar 2023 16:52:14 -0700 Subject: [PATCH] tracing/user_events: Add ABI self-test Add ABI specific self-test to ensure enablements work in various scenarios such as fork, VM_CLONE, and basic event enable/disable. Ensure ABI contracts/limits are also being upheld, such as bit limits and data size limits. Link: https://lkml.kernel.org/r/20230328235219.203-8-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave Signed-off-by: Steven Rostedt (Google) --- tools/testing/selftests/user_events/Makefile | 2 +- tools/testing/selftests/user_events/abi_test.c | 226 +++++++++++++++++++++++++ 2 files changed, 227 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/user_events/abi_test.c diff --git a/tools/testing/selftests/user_events/Makefile b/tools/testing/selftests/user_events/Makefile index 6b512b8..9e95bd4 100644 --- a/tools/testing/selftests/user_events/Makefile +++ b/tools/testing/selftests/user_events/Makefile @@ -10,7 +10,7 @@ LDLIBS += -lrt -lpthread -lm # This test will not compile until user_events.h is added # back to uapi. -TEST_GEN_PROGS = ftrace_test dyn_test perf_test +TEST_GEN_PROGS = ftrace_test dyn_test perf_test abi_test TEST_FILES := settings diff --git a/tools/testing/selftests/user_events/abi_test.c b/tools/testing/selftests/user_events/abi_test.c new file mode 100644 index 0000000..e0323d3 --- /dev/null +++ b/tools/testing/selftests/user_events/abi_test.c @@ -0,0 +1,226 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * User Events ABI Test Program + * + * Copyright (c) 2022 Beau Belgrave + */ + +#define _GNU_SOURCE +#include + +#include +#include +#include +#include +#include +#include +#include +#include +#include + +#include "../kselftest_harness.h" + +const char *data_file = "/sys/kernel/tracing/user_events_data"; +const char *enable_file = "/sys/kernel/tracing/events/user_events/__abi_event/enable"; + +static int change_event(bool enable) +{ + int fd = open(enable_file, O_RDWR); + int ret; + + if (fd < 0) + return -1; + + if (enable) + ret = write(fd, "1", 1); + else + ret = write(fd, "0", 1); + + close(fd); + + if (ret == 1) + ret = 0; + else + ret = -1; + + return ret; +} + +static int reg_enable(long *enable, int size, int bit) +{ + struct user_reg reg = {0}; + int fd = open(data_file, O_RDWR); + int ret; + + if (fd < 0) + return -1; + + reg.size = sizeof(reg); + reg.name_args = (__u64)"__abi_event"; + reg.enable_bit = bit; + reg.enable_addr = (__u64)enable; + reg.enable_size = size; + + ret = ioctl(fd, DIAG_IOCSREG, ®); + + close(fd); + + return ret; +} + +static int reg_disable(long *enable, int bit) +{ + struct user_unreg reg = {0}; + int fd = open(data_file, O_RDWR); + int ret; + + if (fd < 0) + return -1; + + reg.size = sizeof(reg); + reg.disable_bit = bit; + reg.disable_addr = (__u64)enable; + + ret = ioctl(fd, DIAG_IOCSUNREG, ®); + + close(fd); + + return ret; +} + +FIXTURE(user) { + long check; +}; + +FIXTURE_SETUP(user) { + change_event(false); + self->check = 0; +} + +FIXTURE_TEARDOWN(user) { +} + +TEST_F(user, enablement) { + /* Changes should be reflected immediately */ + ASSERT_EQ(0, self->check); + ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0)); + ASSERT_EQ(0, change_event(true)); + ASSERT_EQ(1, self->check); + ASSERT_EQ(0, change_event(false)); + ASSERT_EQ(0, self->check); + + /* Should not change after disable */ + ASSERT_EQ(0, change_event(true)); + ASSERT_EQ(1, self->check); + ASSERT_EQ(0, reg_disable(&self->check, 0)); + ASSERT_EQ(0, change_event(false)); + ASSERT_EQ(1, self->check); + self->check = 0; +} + +TEST_F(user, bit_sizes) { + /* Allow 0-31 bits for 32-bit */ + ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0)); + ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 31)); + ASSERT_NE(0, reg_enable(&self->check, sizeof(int), 32)); + ASSERT_EQ(0, reg_disable(&self->check, 0)); + ASSERT_EQ(0, reg_disable(&self->check, 31)); + +#if BITS_PER_LONG == 8 + /* Allow 0-64 bits for 64-bit */ + ASSERT_EQ(0, reg_enable(&self->check, sizeof(long), 63)); + ASSERT_NE(0, reg_enable(&self->check, sizeof(long), 64)); + ASSERT_EQ(0, reg_disable(&self->check, 63)); +#endif + + /* Disallowed sizes (everything beside 4 and 8) */ + ASSERT_NE(0, reg_enable(&self->check, 1, 0)); + ASSERT_NE(0, reg_enable(&self->check, 2, 0)); + ASSERT_NE(0, reg_enable(&self->check, 3, 0)); + ASSERT_NE(0, reg_enable(&self->check, 5, 0)); + ASSERT_NE(0, reg_enable(&self->check, 6, 0)); + ASSERT_NE(0, reg_enable(&self->check, 7, 0)); + ASSERT_NE(0, reg_enable(&self->check, 9, 0)); + ASSERT_NE(0, reg_enable(&self->check, 128, 0)); +} + +TEST_F(user, forks) { + int i; + + /* Ensure COW pages get updated after fork */ + ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0)); + ASSERT_EQ(0, self->check); + + if (fork() == 0) { + /* Force COW */ + self->check = 0; + + /* Up to 1 sec for enablement */ + for (i = 0; i < 10; ++i) { + usleep(100000); + + if (self->check) + exit(0); + } + + exit(1); + } + + /* Allow generous time for COW, then enable */ + usleep(100000); + ASSERT_EQ(0, change_event(true)); + + ASSERT_NE(-1, wait(&i)); + ASSERT_EQ(0, WEXITSTATUS(i)); + + /* Ensure child doesn't disable parent */ + if (fork() == 0) + exit(reg_disable(&self->check, 0)); + + ASSERT_NE(-1, wait(&i)); + ASSERT_EQ(0, WEXITSTATUS(i)); + ASSERT_EQ(1, self->check); + ASSERT_EQ(0, change_event(false)); + ASSERT_EQ(0, self->check); +} + +/* Waits up to 1 sec for enablement */ +static int clone_check(void *check) +{ + int i; + + for (i = 0; i < 10; ++i) { + usleep(100000); + + if (*(long *)check) + return 0; + } + + return 1; +} + +TEST_F(user, clones) { + int i, stack_size = 4096; + void *stack = mmap(NULL, stack_size, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANONYMOUS | MAP_STACK, + -1, 0); + + ASSERT_NE(MAP_FAILED, stack); + ASSERT_EQ(0, reg_enable(&self->check, sizeof(int), 0)); + ASSERT_EQ(0, self->check); + + /* Shared VM should see enablements */ + ASSERT_NE(-1, clone(&clone_check, stack + stack_size, + CLONE_VM | SIGCHLD, &self->check)); + + ASSERT_EQ(0, change_event(true)); + ASSERT_NE(-1, wait(&i)); + ASSERT_EQ(0, WEXITSTATUS(i)); + munmap(stack, stack_size); + ASSERT_EQ(0, change_event(false)); +} + +int main(int argc, char **argv) +{ + return test_harness_run(argc, argv); +} -- 2.7.4