There are three different strategies to uniquely identify a futex in the kernel: - Private futexes: uses the pointer to mm_struct and the page address - Shared futexes: checks if the page containing the address is a PageAnon: - If it is, uses the same data as a private futexes - If it isn't, uses an inode sequence number from struct inode and the page's index

Create a selftest to check those three paths and basic wait/wake mechanism.

Signed-off-by: André Almeida andrealmeid@collabora.com --- .../selftests/futex/functional/.gitignore | 1 + .../selftests/futex/functional/Makefile | 3 +- .../selftests/futex/functional/futex_wait.c | 171 ++++++++++++++++++ .../testing/selftests/futex/functional/run.sh | 3 + 4 files changed, 177 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/futex/functional/futex_wait.c

diff --git a/tools/testing/selftests/futex/functional/.gitignore b/tools/testing/selftests/futex/functional/.gitignore index 0efcd494daab..bd24699bacc9 100644 --- a/tools/testing/selftests/futex/functional/.gitignore +++ b/tools/testing/selftests/futex/functional/.gitignore @@ -6,3 +6,4 @@ futex_wait_private_mapped_file futex_wait_timeout futex_wait_uninitialized_heap futex_wait_wouldblock +futex_wait diff --git a/tools/testing/selftests/futex/functional/Makefile b/tools/testing/selftests/futex/functional/Makefile index 1d2b3b2a5b86..20a5b4a1bc87 100644 --- a/tools/testing/selftests/futex/functional/Makefile +++ b/tools/testing/selftests/futex/functional/Makefile @@ -15,7 +15,8 @@ TEST_GEN_FILES := \ futex_requeue_pi_signal_restart \ futex_requeue_pi_mismatched_ops \ futex_wait_uninitialized_heap \ - futex_wait_private_mapped_file + futex_wait_private_mapped_file \ + futex_wait

TEST_PROGS := run.sh

diff --git a/tools/testing/selftests/futex/functional/futex_wait.c b/tools/testing/selftests/futex/functional/futex_wait.c new file mode 100644 index 000000000000..685140d9b93d --- /dev/null +++ b/tools/testing/selftests/futex/functional/futex_wait.c @@ -0,0 +1,171 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Copyright Collabora Ltd., 2021 + * + * futex cmp requeue test by André Almeida andrealmeid@collabora.com + */ + +#include <pthread.h> +#include <sys/shm.h> +#include <sys/mman.h> +#include <fcntl.h> +#include "logging.h" +#include "futextest.h" + +#define TEST_NAME "futex-wait" +#define timeout_ns 30000000 +#define WAKE_WAIT_US 10000 +#define SHM_PATH "futex_shm_file" + +void *futex; + +void usage(char *prog) +{ + printf("Usage: %s\n", prog); + printf(" -c Use color\n"); + printf(" -h Display this help message\n"); + printf(" -v L Verbosity level: %d=QUIET %d=CRITICAL %d=INFO\n", + VQUIET, VCRITICAL, VINFO); +} + +static void *waiterfn(void *arg) +{ + struct timespec to; + unsigned int flags = 0; + + if (arg) + flags = *((unsigned int *) arg); + + to.tv_sec = 0; + to.tv_nsec = timeout_ns; + + if (futex_wait(futex, 0, &to, flags)) + printf("waiter failed errno %d\n", errno); + + return NULL; +} + +int main(int argc, char *argv[]) +{ + int res, ret = RET_PASS, fd, c, shm_id; + u_int32_t f_private = 0, *shared_data; + unsigned int flags = FUTEX_PRIVATE_FLAG; + pthread_t waiter; + void *shm; + + futex = &f_private; + + while ((c = getopt(argc, argv, "cht:v:")) != -1) { + switch (c) { + case 'c': + log_color(1); + break; + case 'h': + usage(basename(argv[0])); + exit(0); + case 'v': + log_verbosity(atoi(optarg)); + break; + default: + usage(basename(argv[0])); + exit(1); + } + } + + ksft_print_header(); + ksft_set_plan(3); + ksft_print_msg("%s: Test futex_wait\n", basename(argv[0])); + + /* Testing a private futex */ + info("Calling private futex_wait on futex: %p\n", futex); + if (pthread_create(&waiter, NULL, waiterfn, (void *) &flags)) + error("pthread_create failed\n", errno); + + usleep(WAKE_WAIT_US); + + info("Calling private futex_wake on futex: %p\n", futex); + res = futex_wake(futex, 1, FUTEX_PRIVATE_FLAG); + if (res != 1) { + ksft_test_result_fail("futex_wake private returned: %d %s\n", + errno, strerror(errno)); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_wake private succeeds\n"); + } + + /* 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); + + *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); + + 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"); + } + + + /* Testing a file backed shared memory */ + fd = open(SHM_PATH, O_RDWR | O_CREAT, S_IRUSR | S_IWUSR); + if (fd < 0) { + perror("open"); + exit(1); + } + + if (ftruncate(fd, sizeof(f_private))) { + perror("ftruncate"); + exit(1); + } + + shm = mmap(NULL, sizeof(f_private), PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0); + if (shm == MAP_FAILED) { + perror("mmap"); + exit(1); + } + + memcpy(shm, &f_private, sizeof(f_private)); + + futex = shm; + + info("Calling shared (file backed) futex_wait on futex: %p\n", futex); + if (pthread_create(&waiter, NULL, waiterfn, NULL)) + error("pthread_create failed\n", errno); + + usleep(WAKE_WAIT_US); + + info("Calling shared (file backed) futex_wake on futex: %p\n", futex); + res = futex_wake(shm, 1, 0); + if (res != 1) { + ksft_test_result_fail("futex_wake shared (file backed) returned: %d %s\n", + errno, strerror(errno)); + ret = RET_FAIL; + } else { + ksft_test_result_pass("futex_wake shared (file backed) succeeds\n"); + } + + /* Freeing resources */ + shmdt(shared_data); + munmap(shm, sizeof(f_private)); + remove(SHM_PATH); + close(fd); + + ksft_print_cnts(); + return ret; +} diff --git a/tools/testing/selftests/futex/functional/run.sh b/tools/testing/selftests/futex/functional/run.sh index 1acb6ace1680..d5e1430bcdca 100755 --- a/tools/testing/selftests/futex/functional/run.sh +++ b/tools/testing/selftests/futex/functional/run.sh @@ -73,3 +73,6 @@ echo echo ./futex_wait_uninitialized_heap $COLOR ./futex_wait_private_mapped_file $COLOR + +echo +./futex_wait $COLOR