[PATCH v7 06/13] user_events: Add self-test for ftrace integration

Beau Belgrave
2021-12-09T22:32:38Z

Tests basic functionality of registering/deregistering, status and
writing data out via ftrace mechanisms within user_events.

Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com>
---
tools/testing/selftests/user_events/Makefile | 9 +
.../selftests/user_events/ftrace_test.c | 205 ++++++++++++++++++
tools/testing/selftests/user_events/settings | 1 +
3 files changed, 215 insertions(+)
create mode 100644 tools/testing/selftests/user_events/Makefile
create mode 100644 tools/testing/selftests/user_events/ftrace_test.c
create mode 100644 tools/testing/selftests/user_events/settings

diff --git a/tools/testing/selftests/user_events/Makefile b/tools/testing/selftests/user_events/Makefile
new file mode 100644
index 000000000000..d66c551a6fe3
--- /dev/null
+++ b/tools/testing/selftests/user_events/Makefile
@@ -0,0 +1,9 @@
+# SPDX-License-Identifier: GPL-2.0
+CFLAGS += -Wl,-no-as-needed -Wall -I../../../../usr/include
+LDLIBS += -lrt -lpthread -lm
+
+TEST_GEN_PROGS = ftrace_test
+
+TEST_FILES := settings
+
+include ../lib.mk
diff --git a/tools/testing/selftests/user_events/ftrace_test.c b/tools/testing/selftests/user_events/ftrace_test.c
new file mode 100644
index 000000000000..9d53717139e6
--- /dev/null
+++ b/tools/testing/selftests/user_events/ftrace_test.c
@@ -0,0 +1,205 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * User Events FTrace Test Program
+ *
+ * Copyright (c) 2021 Beau Belgrave <beaub@linux.microsoft.com>
+ */
+
+#include <errno.h>
+#include <linux/user_events.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <sys/ioctl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include "../kselftest_harness.h"
+
+const char *data_file = "/sys/kernel/debug/tracing/user_events_data";
+const char *status_file = "/sys/kernel/debug/tracing/user_events_status";
+const char *enable_file = "/sys/kernel/debug/tracing/events/user_events/__test_event/enable";
+const char *trace_file = "/sys/kernel/debug/tracing/trace";
+
+static int trace_bytes(void)
+{
+ int fd = open(trace_file, O_RDONLY);
+ char buf[256];
+ int bytes = 0, got;
+
+ if (fd == -1)
+ return -1;
+
+ while (true) {
+ got = read(fd, buf, sizeof(buf));
+
+ if (got == -1)
+ return -1;
+
+ if (got == 0)
+ break;
+
+ bytes += got;
+ }
+
+ close(fd);
+
+ return bytes;
+}
+
+FIXTURE(user) {
+ int status_fd;
+ int data_fd;
+ int enable_fd;
+};
+
+FIXTURE_SETUP(user) {
+ self->status_fd = open(status_file, O_RDONLY);
+ ASSERT_NE(-1, self->status_fd);
+
+ self->data_fd = open(data_file, O_RDWR);
+ ASSERT_NE(-1, self->data_fd);
+
+ self->enable_fd = -1;
+}
+
+FIXTURE_TEARDOWN(user) {
+ close(self->status_fd);
+ close(self->data_fd);
+
+ if (self->enable_fd != -1) {
+ write(self->enable_fd, "0", sizeof("0"));
+ close(self->enable_fd);
+ }
+}
+
+TEST_F(user, register_events) {
+ struct user_reg reg = {0};
+ int page_size = sysconf(_SC_PAGESIZE);
+ char *status_page;
+
+ reg.size = sizeof(reg);
+ reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+
+ status_page = mmap(NULL, page_size, PROT_READ, MAP_SHARED,
+ self->status_fd, 0);
+
+ /* Register should work */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+
+ /* Multiple registers should result in same index */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+
+ /* Ensure disabled */
+ self->enable_fd = open(enable_file, O_RDWR);
+ ASSERT_NE(-1, self->enable_fd);
+ ASSERT_NE(-1, write(self->enable_fd, "0", sizeof("0")))
+
+ /* MMAP should work and be zero'd */
+ ASSERT_NE(MAP_FAILED, status_page);
+ ASSERT_NE(NULL, status_page);
+ ASSERT_EQ(0, status_page[reg.status_index]);
+
+ /* Enable event and ensure bits updated in status */
+ ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1")))
+ ASSERT_EQ(EVENT_STATUS_FTRACE, status_page[reg.status_index]);
+
+ /* Disable event and ensure bits updated in status */
+ ASSERT_NE(-1, write(self->enable_fd, "0", sizeof("0")))
+ ASSERT_EQ(0, status_page[reg.status_index]);
+
+ /* File still open should return -EBUSY for delete */
+ ASSERT_EQ(-1, ioctl(self->data_fd, DIAG_IOCSDEL, "__test_event"));
+ ASSERT_EQ(EBUSY, errno);
+
+ /* Delete should work only after close */
+ close(self->data_fd);
+ self->data_fd = open(data_file, O_RDWR);
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSDEL, "__test_event"));
+
+ /* Unmap should work */
+ ASSERT_EQ(0, munmap(status_page, page_size));
+}
+
+TEST_F(user, write_events) {
+ struct user_reg reg = {0};
+ struct iovec io[3];
+ __u32 field1, field2;
+ int before = 0, after = 0;
+
+ reg.size = sizeof(reg);
+ reg.name_args = (__u64)"__test_event u32 field1; u32 field2";
+
+ field1 = 1;
+ field2 = 2;
+
+ io[0].iov_base = &reg.write_index;
+ io[0].iov_len = sizeof(reg.write_index);
+ io[1].iov_base = &field1;
+ io[1].iov_len = sizeof(field1);
+ io[2].iov_base = &field2;
+ io[2].iov_len = sizeof(field2);
+
+ /* Register should work */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+
+ /* Write should fail on invalid slot with ENOENT */
+ io[0].iov_base = &field2;
+ io[0].iov_len = sizeof(field2);
+ ASSERT_EQ(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ ASSERT_EQ(ENOENT, errno);
+ io[0].iov_base = &reg.write_index;
+ io[0].iov_len = sizeof(reg.write_index);
+
+ /* Enable event */
+ self->enable_fd = open(enable_file, O_RDWR);
+ ASSERT_NE(-1, write(self->enable_fd, "1", sizeof("1")))
+
+ /* Write should make it out to ftrace buffers */
+ before = trace_bytes();
+ ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 3));
+ after = trace_bytes();
+ ASSERT_GT(after, before);
+}
+
+TEST_F(user, write_fault) {
+ struct user_reg reg = {0};
+ struct iovec io[2];
+ int l = sizeof(__u64);
+ void *anon;
+
+ reg.size = sizeof(reg);
+ reg.name_args = (__u64)"__test_event u64 anon";
+
+ anon = mmap(NULL, l, PROT_READ, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
+ ASSERT_NE(MAP_FAILED, anon);
+
+ io[0].iov_base = &reg.write_index;
+ io[0].iov_len = sizeof(reg.write_index);
+ io[1].iov_base = anon;
+ io[1].iov_len = l;
+
+ /* Register should work */
+ ASSERT_EQ(0, ioctl(self->data_fd, DIAG_IOCSREG, &reg));
+ ASSERT_EQ(0, reg.write_index);
+ ASSERT_NE(0, reg.status_index);
+
+ /* Write should work normally */
+ ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 2));
+
+ /* Faulted data should zero fill and work */
+ ASSERT_EQ(0, madvise(anon, l, MADV_DONTNEED));
+ ASSERT_NE(-1, writev(self->data_fd, (const struct iovec *)io, 2));
+ ASSERT_EQ(0, munmap(anon, l));
+}
+
+int main(int argc, char **argv)
+{
+ return test_harness_run(argc, argv);
+}
diff --git a/tools/testing/selftests/user_events/settings b/tools/testing/selftests/user_events/settings
new file mode 100644
index 000000000000..ba4d85f74cd6
--- /dev/null
+++ b/tools/testing/selftests/user_events/settings
@@ -0,0 +1 @@
+timeout=90
--
2.17.1