Changes in v2: - Restore RET_FAIL assignments in error paths to ensure the test's exit code accurately reflects the failure status.
Wake Liu (1): selftests/futex: Check for shmget support at runtime
.../selftests/futex/functional/futex_wait.c | 49 +++++++------ .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++------- 2 files changed, 73 insertions(+), 49 deletions(-)
The futex tests `futex_wait.c` and `futex_waitv.c` rely on the `shmget()` syscall, which may not be available if the kernel is built without System V IPC support (CONFIG_SYSVIPC=n). This can lead to test failures on such systems.
This patch modifies the tests to check for `shmget()` support at runtime by calling it and checking for an `ENOSYS` error. If `shmget()` is not supported, the tests are skipped with a clear message, improving the user experience and preventing false negatives.
This approach is more robust than relying on compile-time checks and ensures that the tests run only when the required kernel features are present.
Signed-off-by: Wake Liu wakel@google.com --- .../selftests/futex/functional/futex_wait.c | 49 +++++++------ .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++------- 2 files changed, 73 insertions(+), 49 deletions(-)
diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 685140d9b93d..17a465313a59 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -48,7 +48,7 @@ static void *waiterfn(void *arg) int main(int argc, char *argv[]) { int res, ret = RET_PASS, fd, c, shm_id; - u_int32_t f_private = 0, *shared_data; + u_int32_t f_private = 0, *shared_data = NULL; unsigned int flags = FUTEX_PRIVATE_FLAG; pthread_t waiter; void *shm; @@ -96,32 +96,35 @@ int main(int argc, char *argv[]) /* Testing an anon page shared memory */ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) { - perror("shmget"); - exit(1); - } - - shared_data = shmat(shm_id, NULL, 0); + if (errno == ENOSYS) { + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + ret = RET_FAIL; + } + } else { + shared_data = shmat(shm_id, NULL, 0);
- *shared_data = 0; - futex = shared_data; + *shared_data = 0; + futex = shared_data;
- info("Calling shared (page anon) futex_wait on futex: %p\n", futex); - if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); + info("Calling shared (page anon) futex_wait on futex: %p\n", futex); + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno);
- usleep(WAKE_WAIT_US); + usleep(WAKE_WAIT_US);
- info("Calling shared (page anon) futex_wake on futex: %p\n", futex); - res = futex_wake(futex, 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared (page anon) returned: %d %s\n", - errno, strerror(errno)); - ret = RET_FAIL; - } else { - ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + info("Calling shared (page anon) futex_wake on futex: %p\n", futex); + res = futex_wake(futex, 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared (page anon) returned: %d %s\n", + errno, strerror(errno)); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + } }
- /* Testing a file backed shared memory */ fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); if (fd < 0) { @@ -161,7 +164,8 @@ int main(int argc, char *argv[]) }
/* Freeing resources */ - shmdt(shared_data); + if (shared_data) + shmdt(shared_data); munmap(shm, sizeof(f_private)); remove(SHM_PATH); close(fd); @@ -169,3 +173,4 @@ int main(int argc, char *argv[]) ksft_print_cnts(); return ret; } + diff --git a/tools/testing/selftests/futex/functional/futex_waitv.c b/tools/testing/selftests/futex/functional/futex_waitv.c index a94337f677e1..034dbfef40cb 100644 --- a/tools/testing/selftests/futex/functional/futex_waitv.c +++ b/tools/testing/selftests/futex/functional/futex_waitv.c @@ -110,40 +110,58 @@ int main(int argc, char *argv[]) }
/* Shared waitv */ - for (i = 0; i < NR_FUTEXES; i++) { - int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); - - if (shm_id < 0) { - perror("shmget"); - exit(1); + bool shm_supported = true; + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); + + if (shm_id < 0) { + if (errno == ENOSYS) { + shm_supported = false; + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + ret = RET_FAIL; + shm_supported = false; } + } else { + shmctl(shm_id, IPC_RMID, NULL); + }
- unsigned int *shared_data = shmat(shm_id, NULL, 0); + if (shm_supported) { + for (i = 0; i < NR_FUTEXES; i++) { + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
- *shared_data = 0; - waitv[i].uaddr = (uintptr_t)shared_data; - waitv[i].flags = FUTEX_32; - waitv[i].val = 0; - waitv[i].__reserved = 0; - } + if (shm_id < 0) { + perror("shmget"); + exit(1); + }
- if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); + unsigned int *shared_data = shmat(shm_id, NULL, 0);
- usleep(WAKE_WAIT_US); + *shared_data = 0; + waitv[i].uaddr = (uintptr_t)shared_data; + waitv[i].flags = FUTEX_32; + waitv[i].val = 0; + waitv[i].__reserved = 0; + }
- res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared returned: %d %s\n", - res ? errno : res, - res ? strerror(errno) : ""); - ret = RET_FAIL; - } else { - ksft_test_result_pass("futex_waitv shared\n"); - } + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno);
- for (i = 0; i < NR_FUTEXES; i++) - shmdt(u64_to_ptr(waitv[i].uaddr)); + usleep(WAKE_WAIT_US); + + res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared returned: %d %s\n", + res ? errno : res, + res ? strerror(errno) : ""); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_waitv shared\n"); + } + + for (i = 0; i < NR_FUTEXES; i++) + shmdt(u64_to_ptr(waitv[i].uaddr)); + }
/* Testing a waiter without FUTEX_32 flag */ waitv[0].flags = FUTEX_PRIVATE_FLAG; @@ -235,3 +253,4 @@ int main(int argc, char *argv[]) ksft_print_cnts(); return ret; } +
On Thu, Aug 07, 2025 at 08:00:42PM +0800, Wake Liu wrote:
The futex tests `futex_wait.c` and `futex_waitv.c` rely on the `shmget()` syscall, which may not be available if the kernel is built without System V IPC support (CONFIG_SYSVIPC=n). This can lead to test failures on such systems.
This patch modifies the tests to check for `shmget()` support at runtime by calling it and checking for an `ENOSYS` error. If `shmget()` is not supported, the tests are skipped with a clear message, improving the user experience and preventing false negatives.
This approach is more robust than relying on compile-time checks and ensures that the tests run only when the required kernel features are present.
Signed-off-by: Wake Liu wakel@google.com
.../selftests/futex/functional/futex_wait.c | 49 +++++++------ .../selftests/futex/functional/futex_waitv.c | 73 ++++++++++++------- 2 files changed, 73 insertions(+), 49 deletions(-)
diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 685140d9b93d..17a465313a59 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -48,7 +48,7 @@ static void *waiterfn(void *arg) int main(int argc, char *argv[]) { int res, ret = RET_PASS, fd, c, shm_id;
- u_int32_t f_private = 0, *shared_data;
- u_int32_t f_private = 0, *shared_data = NULL; unsigned int flags = FUTEX_PRIVATE_FLAG; pthread_t waiter; void *shm;
@@ -96,32 +96,35 @@ int main(int argc, char *argv[]) /* Testing an anon page shared memory */ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) {
perror("shmget");exit(1);- }
- shared_data = shmat(shm_id, NULL, 0);
if (errno == ENOSYS) {ksft_test_result_skip("Kernel does not support System V shared memory\n");} else {ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno));ret = RET_FAIL;
kselftest.h is already keeping track of the failure status. Just call ksft_finished() at the end. Also the whole perror()/exit(1) pattern doesn't really make sense in a kselftest.
}- } else {
shared_data = shmat(shm_id, NULL, 0);
(...)
The futex tests `futex_wait.c` and `futex_waitv.c` rely on the `shmget()` syscall, which may not be available if the kernel is built without System V IPC support (CONFIG_SYSVIPC=n). This can lead to test failures on such systems.
This patch modifies the tests to check for `shmget()` support at runtime by calling it and checking for an `ENOSYS` error. If `shmget()` is not supported, the tests are skipped with a clear message, improving the user experience and preventing false negatives.
This approach is more robust than relying on compile-time checks and ensures that the tests run only when the required kernel features are present.
--- +V3 -> V4: - Use ksft_finished() to simplify test exit. - Replace perror()/exit() with ksft_exit_fail_perror().
Signed-off-by: Wake Liu wakel@google.com --- .../selftests/futex/functional/futex_wait.c | 51 +++++++------ .../selftests/futex/functional/futex_waitv.c | 74 +++++++++++-------- 2 files changed, 72 insertions(+), 53 deletions(-)
diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c index 685140d9b93d..ffe9a94c1267 100644 --- a/tools/testing/selftests/futex/functional/futex_wait.c +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -48,7 +48,7 @@ static void *waiterfn(void *arg) int main(int argc, char *argv[]) { int res, ret = RET_PASS, fd, c, shm_id; - u_int32_t f_private = 0, *shared_data; + u_int32_t f_private = 0, *shared_data = NULL; unsigned int flags = FUTEX_PRIVATE_FLAG; pthread_t waiter; void *shm; @@ -96,32 +96,34 @@ int main(int argc, char *argv[]) /* Testing an anon page shared memory */ shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); if (shm_id < 0) { - perror("shmget"); - exit(1); - } + if (errno == ENOSYS) { + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + } + } else { + shared_data = shmat(shm_id, NULL, 0);
- shared_data = shmat(shm_id, NULL, 0); + *shared_data = 0; + futex = shared_data;
- *shared_data = 0; - futex = shared_data; + info("Calling shared (page anon) futex_wait on futex: %p\n", futex); + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno);
- info("Calling shared (page anon) futex_wait on futex: %p\n", futex); - if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); - - usleep(WAKE_WAIT_US); + usleep(WAKE_WAIT_US);
- info("Calling shared (page anon) futex_wake on futex: %p\n", futex); - res = futex_wake(futex, 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared (page anon) returned: %d %s\n", - errno, strerror(errno)); - ret = RET_FAIL; - } else { - ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + info("Calling shared (page anon) futex_wake on futex: %p\n", futex); + res = futex_wake(futex, 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared (page anon) returned: %d %s\n", + errno, strerror(errno)); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_wake shared (page anon) succeeds\n"); + } }
- /* Testing a file backed shared memory */ fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); if (fd < 0) { @@ -161,11 +163,12 @@ int main(int argc, char *argv[]) }
/* Freeing resources */ - shmdt(shared_data); + if (shared_data) + shmdt(shared_data); munmap(shm, sizeof(f_private)); remove(SHM_PATH); close(fd);
- ksft_print_cnts(); - return ret; + ksft_finished(); } + diff --git a/tools/testing/selftests/futex/functional/futex_waitv.c b/tools/testing/selftests/futex/functional/futex_waitv.c index a94337f677e1..681d78ee869f 100644 --- a/tools/testing/selftests/futex/functional/futex_waitv.c +++ b/tools/testing/selftests/futex/functional/futex_waitv.c @@ -110,40 +110,56 @@ int main(int argc, char *argv[]) }
/* Shared waitv */ - for (i = 0; i < NR_FUTEXES; i++) { - int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); + bool shm_supported = true; + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666); + + if (shm_id < 0) { + if (errno == ENOSYS) { + shm_supported = false; + ksft_test_result_skip("Kernel does not support System V shared memory\n"); + } else { + ksft_test_result_fail("shmget() failed with error: %s\n", strerror(errno)); + shm_supported = false; + } + } else { + shmctl(shm_id, IPC_RMID, NULL); + }
- if (shm_id < 0) { - perror("shmget"); - exit(1); - } + if (shm_supported) { + for (i = 0; i < NR_FUTEXES; i++) { + int shm_id = shmget(IPC_PRIVATE, 4096, IPC_CREAT | 0666);
- unsigned int *shared_data = shmat(shm_id, NULL, 0); + if (shm_id < 0) { + ksft_exit_fail_perror("shmget"); + }
- *shared_data = 0; - waitv[i].uaddr = (uintptr_t)shared_data; - waitv[i].flags = FUTEX_32; - waitv[i].val = 0; - waitv[i].__reserved = 0; - } + unsigned int *shared_data = shmat(shm_id, NULL, 0);
- if (pthread_create(&waiter, NULL, waiterfn, NULL)) - error("pthread_create failed\n", errno); + *shared_data = 0; + waitv[i].uaddr = (uintptr_t)shared_data; + waitv[i].flags = FUTEX_32; + waitv[i].val = 0; + waitv[i].__reserved = 0; + }
- usleep(WAKE_WAIT_US); + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno);
- res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); - if (res != 1) { - ksft_test_result_fail("futex_wake shared returned: %d %s\n", - res ? errno : res, - res ? strerror(errno) : ""); - ret = RET_FAIL; - } else { - ksft_test_result_pass("futex_waitv shared\n"); - } + usleep(WAKE_WAIT_US);
- for (i = 0; i < NR_FUTEXES; i++) - shmdt(u64_to_ptr(waitv[i].uaddr)); + res = futex_wake(u64_to_ptr(waitv[NR_FUTEXES - 1].uaddr), 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared returned: %d %s\n", + res ? errno : res, + res ? strerror(errno) : ""); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_waitv shared\n"); + } + + for (i = 0; i < NR_FUTEXES; i++) + shmdt(u64_to_ptr(waitv[i].uaddr)); + }
/* Testing a waiter without FUTEX_32 flag */ waitv[0].flags = FUTEX_PRIVATE_FLAG; @@ -232,6 +248,6 @@ int main(int argc, char *argv[]) ksft_test_result_pass("futex_waitv invalid clockid\n"); }
- ksft_print_cnts(); - return ret; + ksft_finished(); } +
linux-kselftest-mirror@lists.linaro.org
-
Thomas Weißschuh -
Wake Liu