selftests: futex: Add futex wait test
authorAndré Almeida <andrealmeid@collabora.com>
Mon, 31 May 2021 16:50:35 +0000 (13:50 -0300)
committerThomas Gleixner <tglx@linutronix.de>
Tue, 22 Jun 2021 09:20:15 +0000 (11:20 +0200)
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>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Acked-by: Davidlohr Bueso <dbueso@suse.de>
Link: https://lore.kernel.org/r/20210531165036.41468-2-andrealmeid@collabora.com
tools/testing/selftests/futex/functional/.gitignore
tools/testing/selftests/futex/functional/Makefile
tools/testing/selftests/futex/functional/futex_wait.c [new file with mode: 0644]
tools/testing/selftests/futex/functional/run.sh

index 0efcd494daabfa5fc90ba1b027015e1564087433..bd24699bacc9733b3ac1712658ca77d9a1a86d2a 100644 (file)
@@ -6,3 +6,4 @@ futex_wait_private_mapped_file
 futex_wait_timeout
 futex_wait_uninitialized_heap
 futex_wait_wouldblock
+futex_wait
index 1d2b3b2a5b86b5589f5c5db66c283dfd24beec92..20a5b4a1bc8794568e2253b17f1964c7dfb6accc 100644 (file)
@@ -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 (file)
index 0000000..685140d
--- /dev/null
@@ -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;
+}
index 1acb6ace1680e8f3d6b3ee2dc528c19ddfdb018e..d5e1430bcdca04d34e82eb94bb14a3c163942eb4 100755 (executable)
@@ -73,3 +73,6 @@ echo
 echo
 ./futex_wait_uninitialized_heap $COLOR
 ./futex_wait_private_mapped_file $COLOR
+
+echo
+./futex_wait $COLOR