selftests/bpf: Add tests for sleepable tracepoint programs

Cover all three sleepable tracepoint types (tp_btf.s, raw_tp.s, tp.s)
and sys_exit (via bpf_task_pt_regs) with functional tests using
bpf_copy_from_user() on getcwd. Verify alias and bare SEC variants,
bpf_prog_test_run_raw_tp() with BPF_F_TEST_RUN_ON_CPU rejection,
attach-time rejection on non-faultable tracepoints, and load-time
rejection for sleepable tp_btf on non-faultable tracepoints.

Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/bpf/20260422-sleepable_tracepoints-v13-6-99005dff21ef@meta.com
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>

tools/testing/selftests/bpf/prog_tests/sleepable_tracepoints.c

@@ -0,0 +1,142 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#include <test_progs.h>
+#include <unistd.h>
+#include "test_sleepable_tracepoints.skel.h"
+#include "test_sleepable_tracepoints_fail.skel.h"
+
+static void run_test(struct test_sleepable_tracepoints *skel)
+{
+	char buf[PATH_MAX] = "/";
+
+	skel->bss->target_pid = getpid();
+	skel->bss->prog_triggered = 0;
+	skel->bss->err = 0;
+	skel->bss->copied_byte = 0;
+
+	syscall(__NR_getcwd, buf, sizeof(buf));
+
+	ASSERT_EQ(skel->bss->prog_triggered, 1, "prog_triggered");
+	ASSERT_EQ(skel->bss->err, 0, "err");
+	ASSERT_EQ(skel->bss->copied_byte, '/', "copied_byte");
+}
+
+static void run_auto_attach_test(struct bpf_program *prog,
+				 struct test_sleepable_tracepoints *skel)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach(prog);
+	if (!ASSERT_OK_PTR(link, "prog_attach"))
+		return;
+
+	run_test(skel);
+	bpf_link__destroy(link);
+}
+
+static void test_attach_only(struct bpf_program *prog)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach(prog);
+	if (ASSERT_OK_PTR(link, "attach"))
+		bpf_link__destroy(link);
+}
+
+static void test_attach_reject(struct bpf_program *prog)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach(prog);
+	if (!ASSERT_ERR_PTR(link, "attach_should_fail"))
+		bpf_link__destroy(link);
+}
+
+static void test_raw_tp_bare(struct test_sleepable_tracepoints *skel)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach_raw_tracepoint(skel->progs.handle_raw_tp_bare,
+						  "sys_enter");
+	if (ASSERT_OK_PTR(link, "attach"))
+		bpf_link__destroy(link);
+}
+
+static void test_tp_bare(struct test_sleepable_tracepoints *skel)
+{
+	struct bpf_link *link;
+
+	link = bpf_program__attach_tracepoint(skel->progs.handle_tp_bare,
+					      "syscalls", "sys_enter_getcwd");
+	if (ASSERT_OK_PTR(link, "attach"))
+		bpf_link__destroy(link);
+}
+
+static void test_test_run(struct test_sleepable_tracepoints *skel)
+{
+	__u64 args[2] = {0x1234ULL, 0x5678ULL};
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		.ctx_in = args,
+		.ctx_size_in = sizeof(args),
+	);
+	int fd, err;
+
+	fd = bpf_program__fd(skel->progs.handle_test_run);
+	err = bpf_prog_test_run_opts(fd, &topts);
+	ASSERT_OK(err, "test_run");
+	ASSERT_EQ(topts.retval, args[0] + args[1], "test_run_retval");
+}
+
+static void test_test_run_on_cpu_reject(struct test_sleepable_tracepoints *skel)
+{
+	__u64 args[2] = {};
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		.ctx_in = args,
+		.ctx_size_in = sizeof(args),
+		.flags = BPF_F_TEST_RUN_ON_CPU,
+	);
+	int fd, err;
+
+	fd = bpf_program__fd(skel->progs.handle_test_run);
+	err = bpf_prog_test_run_opts(fd, &topts);
+	ASSERT_ERR(err, "test_run_on_cpu_reject");
+}
+
+void test_sleepable_tracepoints(void)
+{
+	struct test_sleepable_tracepoints *skel;
+
+	skel = test_sleepable_tracepoints__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "open_and_load"))
+		return;
+
+	if (test__start_subtest("tp_btf"))
+		run_auto_attach_test(skel->progs.handle_sys_enter_tp_btf, skel);
+	if (test__start_subtest("raw_tp"))
+		run_auto_attach_test(skel->progs.handle_sys_enter_raw_tp, skel);
+	if (test__start_subtest("tracepoint"))
+		run_auto_attach_test(skel->progs.handle_sys_enter_tp, skel);
+	if (test__start_subtest("sys_exit"))
+		run_auto_attach_test(skel->progs.handle_sys_exit_tp, skel);
+	if (test__start_subtest("tracepoint_alias"))
+		test_attach_only(skel->progs.handle_sys_enter_tp_alias);
+	if (test__start_subtest("raw_tracepoint_alias"))
+		test_attach_only(skel->progs.handle_sys_enter_raw_tp_alias);
+	if (test__start_subtest("raw_tp_bare"))
+		test_raw_tp_bare(skel);
+	if (test__start_subtest("tp_bare"))
+		test_tp_bare(skel);
+	if (test__start_subtest("test_run"))
+		test_test_run(skel);
+	if (test__start_subtest("test_run_on_cpu_reject"))
+		test_test_run_on_cpu_reject(skel);
+	if (test__start_subtest("raw_tp_non_faultable"))
+		test_attach_reject(skel->progs.handle_raw_tp_non_faultable);
+	if (test__start_subtest("tp_non_syscall"))
+		test_attach_reject(skel->progs.handle_tp_non_syscall);
+	if (test__start_subtest("tp_btf_non_faultable_reject"))
+		RUN_TESTS(test_sleepable_tracepoints_fail);
+
+	test_sleepable_tracepoints__destroy(skel);
+}

tools/testing/selftests/bpf/progs/test_sleepable_tracepoints.c

@@ -0,0 +1,112 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <asm/unistd.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_core_read.h>
+#include <bpf/bpf_helpers.h>
+
+char _license[] SEC("license") = "GPL";
+
+int target_pid;
+int prog_triggered;
+long err;
+char copied_byte;
+
+static int copy_getcwd_arg(char *ubuf)
+{
+	err = bpf_copy_from_user(&copied_byte, sizeof(copied_byte), ubuf);
+	if (err)
+		return err;
+
+	prog_triggered = 1;
+	return 0;
+}
+
+SEC("tp_btf.s/sys_enter")
+int BPF_PROG(handle_sys_enter_tp_btf, struct pt_regs *regs, long id)
+{
+	if ((bpf_get_current_pid_tgid() >> 32) != target_pid ||
+	    id != __NR_getcwd)
+		return 0;
+
+	return copy_getcwd_arg((void *)PT_REGS_PARM1_SYSCALL(regs));
+}
+
+SEC("raw_tp.s/sys_enter")
+int BPF_PROG(handle_sys_enter_raw_tp, struct pt_regs *regs, long id)
+{
+	if ((bpf_get_current_pid_tgid() >> 32) != target_pid ||
+	    id != __NR_getcwd)
+		return 0;
+
+	return copy_getcwd_arg((void *)PT_REGS_PARM1_CORE_SYSCALL(regs));
+}
+
+SEC("tp.s/syscalls/sys_enter_getcwd")
+int handle_sys_enter_tp(struct syscall_trace_enter *args)
+{
+	if ((bpf_get_current_pid_tgid() >> 32) != target_pid)
+		return 0;
+
+	return copy_getcwd_arg((void *)args->args[0]);
+}
+
+SEC("tp.s/syscalls/sys_exit_getcwd")
+int handle_sys_exit_tp(struct syscall_trace_exit *args)
+{
+	struct pt_regs *regs;
+
+	if ((bpf_get_current_pid_tgid() >> 32) != target_pid)
+		return 0;
+
+	regs = (struct pt_regs *)bpf_task_pt_regs(bpf_get_current_task_btf());
+	return copy_getcwd_arg((void *)PT_REGS_PARM1_CORE_SYSCALL(regs));
+}
+
+SEC("raw_tp.s")
+int BPF_PROG(handle_raw_tp_bare, struct pt_regs *regs, long id)
+{
+	return 0;
+}
+
+SEC("tp.s")
+int handle_tp_bare(void *ctx)
+{
+	return 0;
+}
+
+SEC("tracepoint.s/syscalls/sys_enter_getcwd")
+int handle_sys_enter_tp_alias(struct syscall_trace_enter *args)
+{
+	return 0;
+}
+
+SEC("raw_tracepoint.s/sys_enter")
+int BPF_PROG(handle_sys_enter_raw_tp_alias, struct pt_regs *regs, long id)
+{
+	return 0;
+}
+
+SEC("raw_tp.s/sys_enter")
+int BPF_PROG(handle_test_run, struct pt_regs *regs, long id)
+{
+	if ((__u64)regs == 0x1234ULL && (__u64)id == 0x5678ULL)
+		return (__u64)regs + (__u64)id;
+
+	return 0;
+}
+
+SEC("raw_tp.s/sched_switch")
+int BPF_PROG(handle_raw_tp_non_faultable, bool preempt,
+	     struct task_struct *prev, struct task_struct *next)
+{
+	return 0;
+}
+
+SEC("tp.s/sched/sched_switch")
+int handle_tp_non_syscall(void *ctx)
+{
+	return 0;
+}

tools/testing/selftests/bpf/progs/test_sleepable_tracepoints_fail.c

@@ -0,0 +1,18 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+char _license[] SEC("license") = "GPL";
+
+/* Sleepable program on a non-faultable tracepoint should fail to load */
+SEC("tp_btf.s/sched_switch")
+__failure __msg("Sleepable program cannot attach to non-faultable tracepoint")
+int BPF_PROG(handle_sched_switch, bool preempt,
+	     struct task_struct *prev, struct task_struct *next)
+{
+	return 0;
+}

tools/testing/selftests/bpf/verifier/sleepable.c

@@ -76,7 +76,20 @@
 	.runs = -1,
 },
 {
-	"sleepable raw tracepoint reject",
+	"sleepable raw tracepoint accept",
+	.insns = {
+	BPF_MOV64_IMM(BPF_REG_0, 0),
+	BPF_EXIT_INSN(),
+	},
+	.prog_type = BPF_PROG_TYPE_TRACING,
+	.expected_attach_type = BPF_TRACE_RAW_TP,
+	.kfunc = "sys_enter",
+	.result = ACCEPT,
+	.flags = BPF_F_SLEEPABLE,
+	.runs = -1,
+},
+{
+	"sleepable raw tracepoint reject non-faultable",
 	.insns = {
 	BPF_MOV64_IMM(BPF_REG_0, 0),
 	BPF_EXIT_INSN(),
@@ -85,7 +98,7 @@
 	.expected_attach_type = BPF_TRACE_RAW_TP,
 	.kfunc = "sched_switch",
 	.result = REJECT,
-	.errstr = "Only fentry/fexit/fsession/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable",
+	.errstr = "Sleepable program cannot attach to non-faultable tracepoint",
 	.flags = BPF_F_SLEEPABLE,
 	.runs = -1,
 },