new file mode 100644
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+eventfd_test
new file mode 100644
@@ -0,0 +1,7 @@
+# SPDX-License-Identifier: GPL-2.0
+
+CFLAGS += $(KHDR_INCLUDES)
+LDLIBS += -lpthread
+TEST_GEN_PROGS := eventfd_test
+
+include ../../lib.mk
new file mode 100644
@@ -0,0 +1,186 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#define _GNU_SOURCE
+#include <errno.h>
+#include <fcntl.h>
+#include <asm/unistd.h>
+#include <linux/time_types.h>
+#include <unistd.h>
+#include <assert.h>
+#include <signal.h>
+#include <pthread.h>
+#include <sys/epoll.h>
+#include <sys/eventfd.h>
+#include "../../kselftest_harness.h"
+
+struct error {
+ int code;
+ char msg[512];
+};
+
+static int error_set(struct error *err, int code, const char *fmt, ...)
+{
+ va_list args;
+ int r;
+
+ if (code == 0 || !err || err->code != 0)
+ return code;
+
+ err->code = code;
+ va_start(args, fmt);
+ r = vsnprintf(err->msg, sizeof(err->msg), fmt, args);
+ assert((size_t)r < sizeof(err->msg));
+ va_end(args);
+
+ return code;
+}
+
+static inline int sys_eventfd2(unsigned int count, int flags)
+{
+ return syscall(__NR_eventfd2, count, flags);
+}
+
+TEST(eventfd01)
+{
+ int fd, flags;
+
+ fd = sys_eventfd2(0, 0);
+ ASSERT_GE(fd, 0);
+
+ flags = fcntl(fd, F_GETFL);
+ // since the kernel automatically added O_RDWR.
+ EXPECT_EQ(flags, O_RDWR);
+
+ close(fd);
+}
+
+TEST(eventfd02)
+{
+ int fd, flags;
+
+ fd = sys_eventfd2(0, EFD_CLOEXEC);
+ ASSERT_GE(fd, 0);
+
+ flags = fcntl(fd, F_GETFD);
+ ASSERT_GT(flags, -1);
+ EXPECT_EQ(flags, FD_CLOEXEC);
+
+ close(fd);
+}
+
+TEST(eventfd03)
+{
+ int fd, flags;
+
+ fd = sys_eventfd2(0, EFD_NONBLOCK);
+ ASSERT_GE(fd, 0);
+
+ flags = fcntl(fd, F_GETFL);
+ ASSERT_GT(flags, -1);
+ EXPECT_EQ(flags & EFD_NONBLOCK, EFD_NONBLOCK);
+ EXPECT_EQ(flags & O_RDWR, O_RDWR);
+
+ close(fd);
+}
+
+TEST(eventfd04)
+{
+ int fd, flags;
+
+ fd = sys_eventfd2(0, EFD_CLOEXEC|EFD_NONBLOCK);
+ ASSERT_GE(fd, 0);
+
+ flags = fcntl(fd, F_GETFL);
+ ASSERT_GT(flags, -1);
+ EXPECT_EQ(flags & EFD_NONBLOCK, EFD_NONBLOCK);
+ EXPECT_EQ(flags & O_RDWR, O_RDWR);
+
+ flags = fcntl(fd, F_GETFD);
+ ASSERT_GT(flags, -1);
+ EXPECT_EQ(flags, FD_CLOEXEC);
+
+ close(fd);
+}
+
+static inline void trim_newline(char *str)
+{
+ char *pos = strrchr(str, '\n');
+
+ if (pos)
+ *pos = '\0';
+}
+
+static int verify_fdinfo(int fd, struct error *err, const char *prefix,
+ size_t prefix_len, const char *expect, ...)
+{
+ char buffer[512] = {0, };
+ char path[512] = {0, };
+ va_list args;
+ FILE *f;
+ char *line = NULL;
+ size_t n = 0;
+ int found = 0;
+ int r;
+
+ va_start(args, expect);
+ r = vsnprintf(buffer, sizeof(buffer), expect, args);
+ assert((size_t)r < sizeof(buffer));
+ va_end(args);
+
+ snprintf(path, sizeof(path), "/proc/self/fdinfo/%d", fd);
+ f = fopen(path, "re");
+ if (!f)
+ return error_set(err, -1, "fdinfo open failed for %d", fd);
+
+ while (getline(&line, &n, f) != -1) {
+ char *val;
+
+ if (strncmp(line, prefix, prefix_len))
+ continue;
+
+ found = 1;
+
+ val = line + prefix_len;
+ r = strcmp(val, buffer);
+ if (r != 0) {
+ trim_newline(line);
+ trim_newline(buffer);
+ error_set(err, -1, "%s '%s' != '%s'",
+ prefix, val, buffer);
+ }
+ break;
+ }
+
+ free(line);
+ fclose(f);
+
+ if (found == 0)
+ return error_set(err, -1, "%s not found for fd %d",
+ prefix, fd);
+
+ return 0;
+}
+
+TEST(eventfd05)
+{
+ struct error err = {0};
+ int fd, ret;
+
+ fd = sys_eventfd2(0, EFD_SEMAPHORE);
+ ASSERT_GE(fd, 0);
+
+ ret = fcntl(fd, F_GETFL);
+ ASSERT_GT(ret, -1);
+ EXPECT_EQ(ret & O_RDWR, O_RDWR);
+
+ // The semaphore could only be obtained from fdinfo.
+ ret = verify_fdinfo(fd, &err, "eventfd-semaphore: ", 19, "1\n");
+ if (ret != 0)
+ ksft_print_msg("eventfd-semaphore check failed, msg: %s\n",
+ err.msg);
+ EXPECT_EQ(ret, 0);
+
+ close(fd);
+}
+
+TEST_HARNESS_MAIN