[PATCH 1/2] selftests: futex: Add futex wait test
From: André Almeida
Date: Mon May 31 2021 - 13:08:55 EST
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@xxxxxxxxxxxxx>
---
.../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@xxxxxxxxxxxxx>
+ */
+
+#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
--
2.31.1