This change includes selftests that validate the expected behavior and
APIs of the new BPF_MAP_TYPE_USER_RINGBUF map type.
Signed-off-by: David Vernet <void@xxxxxxxxxxxxx>
---
.../selftests/bpf/prog_tests/user_ringbuf.c | 587 ++++++++++++++++++
.../selftests/bpf/progs/user_ringbuf_fail.c | 174 ++++++
.../bpf/progs/user_ringbuf_success.c | 220 +++++++
.../testing/selftests/bpf/test_user_ringbuf.h | 35 ++
4 files changed, 1016 insertions(+)
create mode 100644 tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
create mode 100644 tools/testing/selftests/bpf/progs/user_ringbuf_fail.c
create mode 100644 tools/testing/selftests/bpf/progs/user_ringbuf_success.c
create mode 100644 tools/testing/selftests/bpf/test_user_ringbuf.h
diff --git a/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c b/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
new file mode 100644
index 000000000000..d62adb74da73
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/user_ringbuf.c
@@ -0,0 +1,587 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#define _GNU_SOURCE
+#include <linux/compiler.h>
+#include <linux/ring_buffer.h>
+#include <pthread.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/mman.h>
+#include <sys/syscall.h>
+#include <sys/sysinfo.h>
+#include <test_progs.h>
+#include <unistd.h>
+
+#include "user_ringbuf_fail.skel.h"
+#include "user_ringbuf_success.skel.h"
+
+#include "../test_user_ringbuf.h"
+
+static int duration;
+static size_t log_buf_sz = 1 << 20; /* 1 MB */
+static char obj_log_buf[1048576];
+static const long c_sample_size = sizeof(struct sample) + BPF_RINGBUF_HDR_SZ;
+static const long c_ringbuf_size = 1 << 12; /* 1 small page */
+static const long c_max_entries = c_ringbuf_size / c_sample_size;
+
+static void drain_current_samples(void)
+{
+ syscall(__NR_getpgid);
+}
+
+static int write_samples(struct ring_buffer_user *ringbuf, uint32_t num_samples)
+{
+ int i, err = 0;
+
+ // Write some number of samples to the ring buffer.
+ for (i = 0; i < num_samples; i++) {
+ struct sample *entry;
+ int read;
+
+ entry = ring_buffer_user__reserve(ringbuf, sizeof(*entry));
+ if (!entry) {
+ err = -ENOMEM;
+ goto done;
+ }
+
+ entry->pid = getpid();
+ entry->seq = i;
+ entry->value = i * i;
+
+ read = snprintf(entry->comm, sizeof(entry->comm), "%u", i);
+ if (read <= 0) {
+ /* Only invoke CHECK on the error path to avoid spamming
+ * logs with mostly success messages.
+ */
+ CHECK(read <= 0, "snprintf_comm",
+ "Failed to write index %d to comm\n", i);
+ err = read;
+ ring_buffer_user__discard(ringbuf, entry);
+ goto done;
+ }
+
+ ring_buffer_user__submit(ringbuf, entry);
+ }
+
+done:
+ drain_current_samples();
+
+ return err;
+}
+
+static struct user_ringbuf_success*
+open_load_ringbuf_skel(void)
+{
+ struct user_ringbuf_success *skel;
+ int err;
+
+ skel = user_ringbuf_success__open();
+ if (CHECK(!skel, "skel_open", "skeleton open failed\n"))
+ return NULL;
+
+ err = bpf_map__set_max_entries(skel->maps.user_ringbuf,
+ c_ringbuf_size);
+ if (CHECK(err != 0, "set_max_entries", "set max entries failed: %d\n", err))
+ goto cleanup;
+
+ err = bpf_map__set_max_entries(skel->maps.kernel_ringbuf,
+ c_ringbuf_size);
+ if (CHECK(err != 0, "set_max_entries", "set max entries failed: %d\n", err))
+ goto cleanup;
+
+ err = user_ringbuf_success__load(skel);
+ if (CHECK(err != 0, "skel_load", "skeleton load failed\n"))
+ goto cleanup;
+
+ return skel;
+
+cleanup:
+ user_ringbuf_success__destroy(skel);
+ return NULL;
+}
+
+static void test_user_ringbuf_mappings(void)
+{
+ int err, rb_fd;
+ int page_size = getpagesize();
+ void *mmap_ptr;
+ struct user_ringbuf_success *skel;
+
+ skel = open_load_ringbuf_skel();
+ if (!skel)
+ return;
+
+ rb_fd = bpf_map__fd(skel->maps.user_ringbuf);
+ /* cons_pos can be mapped R/O, can't add +X with mprotect. */
+ mmap_ptr = mmap(NULL, page_size, PROT_READ, MAP_SHARED, rb_fd, 0);
+ ASSERT_OK_PTR(mmap_ptr, "ro_cons_pos");
+ ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_WRITE), "write_cons_pos_protect");
+ ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_cons_pos_protect");
+ ASSERT_ERR_PTR(mremap(mmap_ptr, 0, 4 * page_size, MREMAP_MAYMOVE), "wr_prod_pos");
+ err = -errno;
+ ASSERT_EQ(err, -EPERM, "wr_prod_pos_err");
+ ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_ro_cons");
+
+ /* prod_pos can be mapped RW, can't add +X with mprotect. */
+ mmap_ptr = mmap(NULL, page_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+ rb_fd, page_size);
+ ASSERT_OK_PTR(mmap_ptr, "rw_prod_pos");
+ ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_prod_pos_protect");
+ err = -errno;
+ ASSERT_EQ(err, -EACCES, "wr_prod_pos_err");
+ ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw_prod");
+
+ /* data pages can be mapped RW, can't add +X with mprotect. */
+ mmap_ptr = mmap(NULL, page_size, PROT_WRITE, MAP_SHARED, rb_fd,
+ 2 * page_size);
+ ASSERT_OK_PTR(mmap_ptr, "rw_data");
+ ASSERT_ERR(mprotect(mmap_ptr, page_size, PROT_EXEC), "exec_data_protect");
+ err = -errno;
+ ASSERT_EQ(err, -EACCES, "exec_data_err");
+ ASSERT_OK(munmap(mmap_ptr, page_size), "unmap_rw_data");
+
+ user_ringbuf_success__destroy(skel);
+}
+
+static int load_skel_create_ringbufs(struct user_ringbuf_success **skel_out,
+ struct ring_buffer **kern_ringbuf_out,
+ ring_buffer_sample_fn callback,
+ struct ring_buffer_user **user_ringbuf_out)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer *kern_ringbuf = NULL;
+ struct ring_buffer_user *user_ringbuf = NULL;
+ int err = -ENOMEM, rb_fd;
+
+ skel = open_load_ringbuf_skel();
+ if (!skel)
+ return err;
+
+ /* only trigger BPF program for current process */
+ skel->bss->pid = getpid();
+
+ if (kern_ringbuf_out) {
+ rb_fd = bpf_map__fd(skel->maps.kernel_ringbuf);
+ kern_ringbuf = ring_buffer__new(rb_fd, callback, skel, NULL);
+ if (CHECK(!kern_ringbuf, "kern_ringbuf_create",
+ "failed to create kern ringbuf\n"))
+ goto cleanup;
+
+ *kern_ringbuf_out = kern_ringbuf;
+ }
+
+ if (user_ringbuf_out) {
+ rb_fd = bpf_map__fd(skel->maps.user_ringbuf);
+ user_ringbuf = ring_buffer_user__new(rb_fd, NULL);
+ if (CHECK(!user_ringbuf, "user_ringbuf_create",
+ "failed to create user ringbuf\n"))
+ goto cleanup;
+
+ *user_ringbuf_out = user_ringbuf;
+ ASSERT_EQ(skel->bss->read, 0, "no_reads_after_load");
+ }
+
+ err = user_ringbuf_success__attach(skel);
+ if (CHECK(err != 0, "skel_attach", "skeleton attachment failed: %d\n",
+ err))
+ goto cleanup;
+
+ *skel_out = skel;
+ return 0;
+
+cleanup:
+ if (kern_ringbuf_out)
+ *kern_ringbuf_out = NULL;
+ if (user_ringbuf_out)
+ *user_ringbuf_out = NULL;
+ ring_buffer__free(kern_ringbuf);
+ ring_buffer_user__free(user_ringbuf);
+ user_ringbuf_success__destroy(skel);
+ return err;
+}
+
+static int
+load_skel_create_user_ringbuf(struct user_ringbuf_success **skel_out,
+ struct ring_buffer_user **ringbuf_out)
+{
+ return load_skel_create_ringbufs(skel_out, NULL, NULL, ringbuf_out);
+}
+
+static void test_user_ringbuf_commit(void)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer_user *ringbuf;
+ int err;
+
+ err = load_skel_create_user_ringbuf(&skel, &ringbuf);
+ if (err)
+ return;
+
+ ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
+
+ err = write_samples(ringbuf, 2);
+ if (CHECK(err, "write_samples", "failed to write samples: %d\n", err))
+ goto cleanup;
+
+ ASSERT_EQ(skel->bss->read, 2, "num_samples_read_after");
+
+cleanup:
+ ring_buffer_user__free(ringbuf);
+ user_ringbuf_success__destroy(skel);
+}
+
+static void test_user_ringbuf_fill(void)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer_user *ringbuf;
+ int err;
+
+ err = load_skel_create_user_ringbuf(&skel, &ringbuf);
+ if (err)
+ return;
+
+ err = write_samples(ringbuf, c_max_entries * 5);
+ ASSERT_EQ(err, -ENOMEM, "too_many_samples_posted");
+ ASSERT_EQ(skel->bss->read, c_max_entries, "max_entries");
+
+ ring_buffer_user__free(ringbuf);
+ user_ringbuf_success__destroy(skel);
+}
+
+static void test_user_ringbuf_loop(void)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer_user *ringbuf;
+ uint32_t total_samples = 8192;
+ uint32_t remaining_samples = total_samples;
+ int err;
+
+ err = load_skel_create_user_ringbuf(&skel, &ringbuf);
+ if (err)
+ return;
+
+ do {
+ uint32_t curr_samples;
+
+ curr_samples = remaining_samples > c_max_entries
+ ? c_max_entries : remaining_samples;
+ err = write_samples(ringbuf, curr_samples);
+ if (err != 0) {
+ /* Perform CHECK inside of if statement to avoid
+ * flooding logs on the success path.
+ */
+ CHECK(err, "write_samples",
+ "failed to write sample batch: %d\n", err);
+ goto cleanup;
+ }
+
+ remaining_samples -= curr_samples;
+ ASSERT_EQ(skel->bss->read, total_samples - remaining_samples,
+ "current_batched_entries");
+ } while (remaining_samples > 0);
+ ASSERT_EQ(skel->bss->read, total_samples, "total_batched_entries");
+
+cleanup:
+ ring_buffer_user__free(ringbuf);
+ user_ringbuf_success__destroy(skel);
+}
+
+static int send_test_message(struct ring_buffer_user *ringbuf,
+ enum test_msg_op op, s64 operand_64,
+ s32 operand_32)
+{
+ struct test_msg *msg;
+
+ msg = ring_buffer_user__reserve(ringbuf, sizeof(*msg));
+ if (!msg) {
+ /* Only invoke CHECK on the error path to avoid spamming
+ * logs with mostly success messages.
+ */
+ CHECK(msg != NULL, "reserve_msg",
+ "Failed to reserve message\n");
+ return -ENOMEM;
+ }
+
+ msg->msg_op = op;
+
+ switch (op) {
+ case TEST_MSG_OP_INC64:
+ case TEST_MSG_OP_MUL64:
+ msg->operand_64 = operand_64;
+ break;
+ case TEST_MSG_OP_INC32:
+ case TEST_MSG_OP_MUL32:
+ msg->operand_32 = operand_32;
+ break;
+ default:
+ PRINT_FAIL("Invalid operand %d\n", op);
+ ring_buffer_user__discard(ringbuf, msg);
+ return -EINVAL;
+ }
+
+ ring_buffer_user__submit(ringbuf, msg);
+
+ return 0;
+}
+
+static void kick_kernel_read_messages(void)
+{
+ syscall(__NR_getcwd);
+}
+
+static int handle_kernel_msg(void *ctx, void *data, size_t len)
+{
+ struct user_ringbuf_success *skel = ctx;
+ struct test_msg *msg = data;
+
+ switch (msg->msg_op) {
+ case TEST_MSG_OP_INC64:
+ skel->bss->user_mutated += msg->operand_64;
+ return 0;
+ case TEST_MSG_OP_INC32:
+ skel->bss->user_mutated += msg->operand_32;
+ return 0;
+ case TEST_MSG_OP_MUL64:
+ skel->bss->user_mutated *= msg->operand_64;
+ return 0;
+ case TEST_MSG_OP_MUL32:
+ skel->bss->user_mutated *= msg->operand_32;
+ return 0;
+ default:
+ fprintf(stderr, "Invalid operand %d\n", msg->msg_op);
+ return -EINVAL;
+ }
+}
+
+static void drain_kernel_messages_buffer(struct ring_buffer *kern_ringbuf)
+{
+ int err;
+
+ err = ring_buffer__consume(kern_ringbuf);
+ if (err)
+ /* Only check in failure to avoid spamming success logs. */
+ CHECK(!err, "consume_kern_ringbuf",
+ "Failed to consume kernel ringbuf\n");
+}
+
+static void test_user_ringbuf_msg_protocol(void)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer_user *user_ringbuf;
+ struct ring_buffer *kern_ringbuf;
+ int err, i;
+ __u64 expected_kern = 0;
+
+ err = load_skel_create_ringbufs(&skel, &kern_ringbuf, handle_kernel_msg,
+ &user_ringbuf);
+ if (CHECK(err, "create_ringbufs", "Failed to create ringbufs: %d\n",
+ err))
+ return;
+
+ for (i = 0; i < 64; i++) {
+ enum test_msg_op op = i % TEST_MSG_OP_NUM_OPS;
+ __u64 operand_64 = TEST_OP_64;
+ __u32 operand_32 = TEST_OP_32;
+
+ err = send_test_message(user_ringbuf, op, operand_64,
+ operand_32);
+ if (err) {
+ CHECK(err, "send_test_message",
+ "Failed to send test message\n");
+ goto cleanup;
+ }
+
+ switch (op) {
+ case TEST_MSG_OP_INC64:
+ expected_kern += operand_64;
+ break;
+ case TEST_MSG_OP_INC32:
+ expected_kern += operand_32;
+ break;
+ case TEST_MSG_OP_MUL64:
+ expected_kern *= operand_64;
+ break;
+ case TEST_MSG_OP_MUL32:
+ expected_kern *= operand_32;
+ break;
+ default:
+ PRINT_FAIL("Unexpected op %d\n", op);
+ goto cleanup;
+ }
+
+ if (i % 8 == 0) {
+ kick_kernel_read_messages();
+ ASSERT_EQ(skel->bss->kern_mutated, expected_kern,
+ "expected_kern");
+ ASSERT_EQ(skel->bss->err, 0, "bpf_prog_err");
+ drain_kernel_messages_buffer(kern_ringbuf);
+ }
+ }
+
+cleanup:
+ ring_buffer__free(kern_ringbuf);
+ ring_buffer_user__free(user_ringbuf);
+ user_ringbuf_success__destroy(skel);
+}
+
+static void *kick_kernel_cb(void *arg)
+{
+ /* Sleep to better exercise the path for the main thread waiting in
+ * poll_wait().
+ */
+ sleep(1);
+
+ /* Kick the kernel, causing it to drain the ringbuffer and then wake up
+ * the test thread waiting on epoll.
+ */
+ syscall(__NR_getrlimit);
+
+ return NULL;
+}
+
+static int spawn_kick_thread_for_poll(void)
+{
+ pthread_t thread;
+
+ return pthread_create(&thread, NULL, kick_kernel_cb, NULL);
+}
+
+static void test_user_ringbuf_poll_wait(void)
+{
+ struct user_ringbuf_success *skel;
+ struct ring_buffer_user *ringbuf;
+ int err, num_written = 0;
+ __u64 *token;
+
+ err = load_skel_create_user_ringbuf(&skel, &ringbuf);
+ if (err)
+ return;
+
+ ASSERT_EQ(skel->bss->read, 0, "num_samples_read_before");
+
+ while (1) {
+ /* Write samples until the buffer is full. */
+ token = ring_buffer_user__reserve(ringbuf, sizeof(*token));
+ if (!token)
+ break;
+
+ *token = 0xdeadbeef;
+
+ ring_buffer_user__submit(ringbuf, token);
+ num_written++;
+ }
+
+ if (!ASSERT_GE(num_written, 0, "num_written"))
+ goto cleanup;
+
+ /* Should not have read any samples until the kernel is kicked. */
+ ASSERT_EQ(skel->bss->read, 0, "num_pre_kick");
+
+ token = ring_buffer_user__poll(ringbuf, sizeof(*token), 1000);
+ if (!ASSERT_EQ(token, NULL, "pre_kick_timeout_token"))
+ goto cleanup;
+
+ err = spawn_kick_thread_for_poll();
+ if (!ASSERT_EQ(err, 0, "deferred_kick_thread\n"))
+ goto cleanup;
+
+ token = ring_buffer_user__poll(ringbuf, sizeof(*token), 10000);
+ if (!token) {
+ PRINT_FAIL("Failed to poll for user ringbuf entry\n");
+ ring_buffer_user__discard(ringbuf, token);
+ goto cleanup;
+ }
+
+ ASSERT_EQ(skel->bss->read, num_written, "num_post_kill");
+ ASSERT_EQ(skel->bss->err, 0, "err_post_poll");
+ ring_buffer_user__discard(ringbuf, token);
+
+cleanup:
+ ring_buffer_user__free(ringbuf);
+ user_ringbuf_success__destroy(skel);
+}
+
+static struct {
+ const char *prog_name;
+ const char *expected_err_msg;
+} failure_tests[] = {
+ /* failure cases */
+ {"user_ringbuf_callback_bad_access1", "negative offset alloc_dynptr_ptr ptr"},
+ {"user_ringbuf_callback_bad_access2", "dereference of modified alloc_dynptr_ptr ptr"},
+ {"user_ringbuf_callback_write_forbidden", "invalid mem access 'alloc_dynptr_ptr'"},
+ {"user_ringbuf_callback_null_context_write", "invalid mem access 'scalar'"},
+ {"user_ringbuf_callback_null_context_read", "invalid mem access 'scalar'"},
+ {"user_ringbuf_callback_discard_dynptr", "arg 1 is an unacquired reference"},
+ {"user_ringbuf_callback_submit_dynptr", "arg 1 is an unacquired reference"},
+};
+
+#define SUCCESS_TEST(_func) { _func, #_func }
+
+static struct {
+ void (*test_callback)(void);
+ const char *test_name;
+} success_tests[] = {
+ SUCCESS_TEST(test_user_ringbuf_mappings),
+ SUCCESS_TEST(test_user_ringbuf_commit),
+ SUCCESS_TEST(test_user_ringbuf_fill),
+ SUCCESS_TEST(test_user_ringbuf_loop),
+ SUCCESS_TEST(test_user_ringbuf_msg_protocol),
+ SUCCESS_TEST(test_user_ringbuf_poll_wait),
+};
+
+static void verify_fail(const char *prog_name, const char *expected_err_msg)
+{
+ LIBBPF_OPTS(bpf_object_open_opts, opts);
+ struct bpf_program *prog;
+ struct user_ringbuf_fail *skel;
+ int err;
+
+ opts.kernel_log_buf = obj_log_buf;
+ opts.kernel_log_size = log_buf_sz;
+ opts.kernel_log_level = 1;
+
+ skel = user_ringbuf_fail__open_opts(&opts);
+ if (!ASSERT_OK_PTR(skel, "dynptr_fail__open_opts"))
+ goto cleanup;
+
+ prog = bpf_object__find_program_by_name(skel->obj, prog_name);
+ if (!ASSERT_OK_PTR(prog, "bpf_object__find_program_by_name"))
+ goto cleanup;
+
+ bpf_program__set_autoload(prog, true);
+
+ bpf_map__set_max_entries(skel->maps.user_ringbuf, getpagesize());
+
+ err = user_ringbuf_fail__load(skel);
+ if (!ASSERT_ERR(err, "unexpected load success"))
+ goto cleanup;
+
+ if (!ASSERT_OK_PTR(strstr(obj_log_buf, expected_err_msg), "expected_err_msg")) {
+ fprintf(stderr, "Expected err_msg: %s\n", expected_err_msg);
+ fprintf(stderr, "Verifier output: %s\n", obj_log_buf);
+ }
+
+cleanup:
+ user_ringbuf_fail__destroy(skel);
+}
+
+void test_user_ringbuf(void)
+{
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(success_tests); i++) {
+ if (!test__start_subtest(success_tests[i].test_name))
+ continue;
+
+ success_tests[i].test_callback();
+ }
+
+ for (i = 0; i < ARRAY_SIZE(failure_tests); i++) {
+ if (!test__start_subtest(failure_tests[i].prog_name))
+ continue;
+
+ verify_fail(failure_tests[i].prog_name,
+ failure_tests[i].expected_err_msg);
+ }
+}
diff --git a/tools/testing/selftests/bpf/progs/user_ringbuf_fail.c b/tools/testing/selftests/bpf/progs/user_ringbuf_fail.c
new file mode 100644
index 000000000000..237df8ca637a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/user_ringbuf_fail.c
@@ -0,0 +1,174 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+struct sample {
+ int pid;
+ int seq;
+ long value;
+ char comm[16];
+};
+
+struct {
+ __uint(type, BPF_MAP_TYPE_USER_RINGBUF);
+} user_ringbuf SEC(".maps");
+
+static long
+bad_access1(struct bpf_dynptr *dynptr, void *context)
+{
+ const struct sample *sample;
+
+ sample = bpf_dynptr_data(dynptr - 1, 0, sizeof(*sample));
+ bpf_printk("Was able to pass bad pointer %lx\n", (__u64)dynptr - 1);
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to read before the pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_bad_access1(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, bad_access1, NULL, 0);
+
+ return 0;
+}
+
+static long
+bad_access2(struct bpf_dynptr *dynptr, void *context)
+{
+ const struct sample *sample;
+
+ sample = bpf_dynptr_data(dynptr + 1, 0, sizeof(*sample));
+ bpf_printk("Was able to pass bad pointer %lx\n", (__u64)dynptr + 1);
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to read past the end of the pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_bad_access2(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, bad_access2, NULL, 0);
+
+ return 0;
+}
+
+static long
+write_forbidden(struct bpf_dynptr *dynptr, void *context)
+{
+ *((long *)dynptr) = 0;
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to write to that pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_write_forbidden(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, write_forbidden, NULL, 0);
+
+ return 0;
+}
+
+static long
+null_context_write(struct bpf_dynptr *dynptr, void *context)
+{
+ *((__u64 *)context) = 0;
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to write to that pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_null_context_write(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, null_context_write, NULL, 0);
+
+ return 0;
+}
+
+static long
+null_context_read(struct bpf_dynptr *dynptr, void *context)
+{
+ __u64 id = *((__u64 *)context);
+
+ bpf_printk("Read id %lu\n", id);
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to write to that pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_null_context_read(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, null_context_read, NULL, 0);
+
+ return 0;
+}
+
+static long
+try_discard_dynptr(struct bpf_dynptr *dynptr, void *context)
+{
+ bpf_ringbuf_discard_dynptr(dynptr, 0);
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to read past the end of the pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_discard_dynptr(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, try_discard_dynptr, NULL, 0);
+
+ return 0;
+}
+
+static long
+try_submit_dynptr(struct bpf_dynptr *dynptr, void *context)
+{
+ bpf_ringbuf_submit_dynptr(dynptr, 0);
+
+ return 0;
+}
+
+/* A callback that accesses a dynptr in a bpf_user_ringbuf_drain callback should
+ * not be able to read past the end of the pointer.
+ */
+SEC("?raw_tp/sys_nanosleep")
+int user_ringbuf_callback_submit_dynptr(void *ctx)
+{
+ struct bpf_dynptr ptr;
+
+ bpf_user_ringbuf_drain(&user_ringbuf, try_submit_dynptr, NULL, 0);
+
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/progs/user_ringbuf_success.c b/tools/testing/selftests/bpf/progs/user_ringbuf_success.c
new file mode 100644
index 000000000000..ab8035a47da5
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/user_ringbuf_success.c
@@ -0,0 +1,220 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+#include "../test_user_ringbuf.h"
+
+char _license[] SEC("license") = "GPL";
+
+struct {
+ __uint(type, BPF_MAP_TYPE_USER_RINGBUF);
+} user_ringbuf SEC(".maps");
+
+struct {
+ __uint(type, BPF_MAP_TYPE_RINGBUF);
+} kernel_ringbuf SEC(".maps");
+
+/* inputs */
+int pid, err, val;
+
+int read = 0;
+
+/* Counter used for end-to-end protocol test */
+__u64 kern_mutated = 0;
+__u64 user_mutated = 0;
+__u64 expected_user_mutated = 0;
+
+static int
+is_test_process(void)
+{
+ int cur_pid = bpf_get_current_pid_tgid() >> 32;
+
+ return cur_pid == pid;
+}
+
+static long
+record_sample(struct bpf_dynptr *dynptr, void *context)
+{
+ const struct sample *sample = NULL;
+ struct sample stack_sample;
+ int status;
+ static int num_calls;
+
+ if (num_calls++ % 2 == 0) {
+ status = bpf_dynptr_read(&stack_sample, sizeof(stack_sample),
+ dynptr, 0, 0);
+ if (status) {
+ bpf_printk("bpf_dynptr_read() failed: %d\n", status);
+ err = 1;
+ return 0;
+ }
+ } else {
+ sample = bpf_dynptr_data(dynptr, 0, sizeof(*sample));
+ if (!sample) {
+ bpf_printk("Unexpectedly failed to get sample\n");
+ err = 2;
+ return 0;
+ }
+ stack_sample = *sample;
+ }
+
+ __sync_fetch_and_add(&read, 1);
+ return 0;
+}
+
+static void
+handle_sample_msg(const struct test_msg *msg)
+{
+ switch (msg->msg_op) {
+ case TEST_MSG_OP_INC64:
+ kern_mutated += msg->operand_64;
+ break;
+ case TEST_MSG_OP_INC32:
+ kern_mutated += msg->operand_32;
+ break;
+ case TEST_MSG_OP_MUL64:
+ kern_mutated *= msg->operand_64;
+ break;
+ case TEST_MSG_OP_MUL32:
+ kern_mutated *= msg->operand_32;
+ break;
+ default:
+ bpf_printk("Unrecognized op %d\n", msg->msg_op);
+ err = 2;
+ }
+}
+
+static long
+read_protocol_msg(struct bpf_dynptr *dynptr, void *context)
+{
+ const struct test_msg *msg = NULL;
+
+ msg = bpf_dynptr_data(dynptr, 0, sizeof(*msg));
+ if (!msg) {
+ err = 1;
+ bpf_printk("Unexpectedly failed to get msg\n");
+ return 0;
+ }
+
+ handle_sample_msg(msg);
+
+ return 0;
+}
+
+static int publish_next_kern_msg(__u32 index, void *context)
+{
+ struct test_msg *msg = NULL;
+ int operand_64 = TEST_OP_64;
+ int operand_32 = TEST_OP_32;
+
+ msg = bpf_ringbuf_reserve(&kernel_ringbuf, sizeof(*msg), 0);
+ if (!msg) {
+ err = 4;
+ return 1;
+ }
+
+ switch (index % TEST_MSG_OP_NUM_OPS) {
+ case TEST_MSG_OP_INC64:
+ msg->operand_64 = operand_64;
+ msg->msg_op = TEST_MSG_OP_INC64;
+ expected_user_mutated += operand_64;
+ break;
+ case TEST_MSG_OP_INC32:
+ msg->operand_32 = operand_32;
+ msg->msg_op = TEST_MSG_OP_INC32;
+ expected_user_mutated += operand_32;
+ break;
+ case TEST_MSG_OP_MUL64:
+ msg->operand_64 = operand_64;
+ msg->msg_op = TEST_MSG_OP_MUL64;
+ expected_user_mutated *= operand_64;
+ break;
+ case TEST_MSG_OP_MUL32:
+ msg->operand_32 = operand_32;
+ msg->msg_op = TEST_MSG_OP_MUL32;
+ expected_user_mutated *= operand_32;
+ break;
+ default:
+ bpf_ringbuf_discard(msg, 0);
+ err = 5;
+ return 1;
+ }
+
+ bpf_ringbuf_submit(msg, 0);
+
+ return 0;
+}
+
+static void
+publish_kern_messages(void)
+{
+ if (expected_user_mutated != user_mutated) {
+ bpf_printk("%d != %d\n", expected_user_mutated, user_mutated);
+ err = 3;
+ return;
+ }
+
+ bpf_loop(8, publish_next_kern_msg, NULL, 0);
+}
+
+SEC("fentry/" SYS_PREFIX "sys_getcwd")
+int test_user_ringbuf_protocol(void *ctx)
+{
+ long status = 0;
+ struct sample *sample = NULL;
+ struct bpf_dynptr ptr;
+
+ if (!is_test_process())
+ return 0;
+
+ status = bpf_user_ringbuf_drain(&user_ringbuf, read_protocol_msg, NULL, 0);
+ if (status < 0) {
+ bpf_printk("Drain returned: %ld\n", status);
+ err = 1;
+ return 0;
+ }
+
+ publish_kern_messages();
+
+ return 0;
+}
+
+SEC("fentry/" SYS_PREFIX "sys_getpgid")
+int test_user_ringbuf(void *ctx)
+{
+ int status = 0;
+ struct sample *sample = NULL;
+ struct bpf_dynptr ptr;
+
+ if (!is_test_process())
+ return 0;
+
+ err = bpf_user_ringbuf_drain(&user_ringbuf, record_sample, NULL, 0);
+
+ return 0;
+}
+
+static long
+do_nothing_cb(struct bpf_dynptr *dynptr, void *context)
+{
+ __sync_fetch_and_add(&read, 1);
+ return 0;
+}
+
+SEC("fentry/" SYS_PREFIX "sys_getrlimit")
+int test_user_ringbuf_epoll(void *ctx)
+{
+ long num_samples;
+
+ if (!is_test_process())
+ return 0;
+
+ num_samples = bpf_user_ringbuf_drain(&user_ringbuf, do_nothing_cb, NULL,
+ 0);
+ if (num_samples <= 0)
+ err = 1;
+
+ return 0;
+}
diff --git a/tools/testing/selftests/bpf/test_user_ringbuf.h b/tools/testing/selftests/bpf/test_user_ringbuf.h
new file mode 100644
index 000000000000..1643b4d59ba7
--- /dev/null
+++ b/tools/testing/selftests/bpf/test_user_ringbuf.h
@@ -0,0 +1,35 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */
+
+#ifndef _TEST_USER_RINGBUF_H
+#define _TEST_USER_RINGBUF_H
+
+#define TEST_OP_64 4
+#define TEST_OP_32 2
+
+enum test_msg_op {
+ TEST_MSG_OP_INC64,
+ TEST_MSG_OP_INC32,
+ TEST_MSG_OP_MUL64,
+ TEST_MSG_OP_MUL32,
+
+ // Must come last.
+ TEST_MSG_OP_NUM_OPS,
+};
+
+struct test_msg {
+ enum test_msg_op msg_op;
+ union {
+ __s64 operand_64;
+ __s32 operand_32;
+ };
+};
+
+struct sample {
+ int pid;
+ int seq;
+ long value;
+ char comm[16];
+};
+
+#endif /* _TEST_USER_RINGBUF_H */
--
2.37.1
