Re: [PATCH bpf-next v2 6/6] selftests/bpf: Add tests for sleepable raw tracepoint programs

[Mykyta Yatsenko <mykyta.yatsenko5@gmail.com>]

On 3/9/26 9:11 PM, Jiri Olsa wrote:
> On Wed, Feb 25, 2026 at 08:23:54AM -0800, Mykyta Yatsenko wrote:
>> From: Mykyta Yatsenko <yatsenko@meta.com>
>>
>> Add two subtests:
>> - success: Attach a sleepable BPF program to the faultable sys_enter
>>    tracepoint (tp_btf.s/sys_enter). Verify the program is triggered by
>>    a syscall.
>> - reject_non_faultable: Attempt to attach a sleepable BPF program to
>>    a non-faultable tracepoint (tp_btf.s/sched_switch). Verify that
>>    attachment is rejected.
>>
>> Signed-off-by: Mykyta Yatsenko <yatsenko@meta.com>
>> ---
>>   .../selftests/bpf/prog_tests/sleepable_raw_tp.c    | 56 ++++++++++++++++++++++
>>   .../selftests/bpf/progs/test_sleepable_raw_tp.c    | 43 +++++++++++++++++
>>   .../bpf/progs/test_sleepable_raw_tp_fail.c         | 16 +++++++
>>   tools/testing/selftests/bpf/verifier/sleepable.c   |  5 +-
>>   4 files changed, 117 insertions(+), 3 deletions(-)
>>
>> diff --git a/tools/testing/selftests/bpf/prog_tests/sleepable_raw_tp.c b/tools/testing/selftests/bpf/prog_tests/sleepable_raw_tp.c
>> new file mode 100644
>> index 000000000000..9b0ec7cc4cac
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/sleepable_raw_tp.c
>> @@ -0,0 +1,56 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2025 Meta Platforms, Inc. and affiliates. */
>> +
>> +#include <test_progs.h>
>> +#include <time.h>
>> +#include "test_sleepable_raw_tp.skel.h"
>> +#include "test_sleepable_raw_tp_fail.skel.h"
>> +
>> +static void test_sleepable_raw_tp_success(void)
>> +{
>> +	struct test_sleepable_raw_tp *skel;
>> +	int err;
>> +
>> +	skel = test_sleepable_raw_tp__open_and_load();
>> +	if (!ASSERT_OK_PTR(skel, "skel_open_load"))
>> +		return;
>> +
>> +	skel->bss->target_pid = getpid();
>> +
>> +	err = test_sleepable_raw_tp__attach(skel);
>> +	if (!ASSERT_OK(err, "skel_attach"))
>> +		goto cleanup;
>> +
>> +	syscall(__NR_nanosleep, &(struct timespec){ .tv_nsec = 555 }, NULL);
>> +
>> +	ASSERT_EQ(skel->bss->triggered, 1, "triggered");
>> +	ASSERT_EQ(skel->bss->err, 0, "err");
>> +	ASSERT_EQ(skel->bss->copied_tv_nsec, 555, "copied_tv_nsec");
>> +
>> +cleanup:
>> +	test_sleepable_raw_tp__destroy(skel);
>> +}
>> +
>> +static void test_sleepable_raw_tp_reject(void)
>> +{
>> +	struct test_sleepable_raw_tp_fail *skel;
>> +	int err;
>> +
>> +	skel = test_sleepable_raw_tp_fail__open_and_load();
>> +	if (!ASSERT_OK_PTR(skel, "skel_open_load"))
>> +		goto cleanup;
>> +
>> +	err = test_sleepable_raw_tp_fail__attach(skel);
>> +	ASSERT_ERR(err, "skel_attach_should_fail");
> 
> would it be better to call RUN_TESTS(test_sleepable_raw_tp_fail) instead?
> you could also check the verifier output
> 
> jirka
yes, definitely, thanks!
> 
> 
>> +
>> +cleanup:
>> +	test_sleepable_raw_tp_fail__destroy(skel);
>> +}
>> +
>> +void test_sleepable_raw_tp(void)
>> +{
>> +	if (test__start_subtest("success"))
>> +		test_sleepable_raw_tp_success();
>> +	if (test__start_subtest("reject_non_faultable"))
>> +		test_sleepable_raw_tp_reject();
>> +}
>> diff --git a/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp.c b/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp.c
>> new file mode 100644
>> index 000000000000..ebacc766df57
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp.c
>> @@ -0,0 +1,43 @@
>> +// 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 triggered;
>> +long err;
>> +long copied_tv_nsec;
>> +
>> +SEC("tp_btf.s/sys_enter")
>> +int BPF_PROG(test_sleepable_sys_enter, struct pt_regs *regs, long id)
>> +{
>> +	struct task_struct *task = bpf_get_current_task_btf();
>> +	struct __kernel_timespec *ts;
>> +	long tv_nsec;
>> +
>> +	if (task->pid != target_pid)
>> +		return 0;
>> +
>> +	if (id != __NR_nanosleep)
>> +		return 0;
>> +
>> +	ts = (void *)PT_REGS_PARM1_CORE_SYSCALL(regs);
>> +
>> +	/*
>> +	 * Use bpf_copy_from_user() - a sleepable helper - to read user memory.
>> +	 * This exercises the sleepable execution path of raw tracepoints.
>> +	 */
>> +	err = bpf_copy_from_user(&tv_nsec, sizeof(tv_nsec), &ts->tv_nsec);
>> +	if (err)
>> +		return err;
>> +
>> +	copied_tv_nsec = tv_nsec;
>> +	triggered = 1;
>> +	return 0;
>> +}
>> diff --git a/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp_fail.c b/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp_fail.c
>> new file mode 100644
>> index 000000000000..ef5dc3888df6
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/test_sleepable_raw_tp_fail.c
>> @@ -0,0 +1,16 @@
>> +// 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>
>> +
>> +char _license[] SEC("license") = "GPL";
>> +
>> +/* Sleepable program on a non-faultable tracepoint should fail at attach */
>> +SEC("tp_btf.s/sched_switch")
>> +int BPF_PROG(test_sleepable_sched_switch, bool preempt,
>> +	     struct task_struct *prev, struct task_struct *next)
>> +{
>> +	return 0;
>> +}
>> diff --git a/tools/testing/selftests/bpf/verifier/sleepable.c b/tools/testing/selftests/bpf/verifier/sleepable.c
>> index 1f0d2bdc673f..39522b7cd317 100644
>> --- a/tools/testing/selftests/bpf/verifier/sleepable.c
>> +++ b/tools/testing/selftests/bpf/verifier/sleepable.c
>> @@ -76,7 +76,7 @@
>>   	.runs = -1,
>>   },
>>   {
>> -	"sleepable raw tracepoint reject",
>> +	"sleepable raw tracepoint accept",
>>   	.insns = {
>>   	BPF_MOV64_IMM(BPF_REG_0, 0),
>>   	BPF_EXIT_INSN(),
>> @@ -84,8 +84,7 @@
>>   	.prog_type = BPF_PROG_TYPE_TRACING,
>>   	.expected_attach_type = BPF_TRACE_RAW_TP,
>>   	.kfunc = "sched_switch",
>> -	.result = REJECT,
>> -	.errstr = "Only fentry/fexit/fmod_ret, lsm, iter, uprobe, and struct_ops programs can be sleepable",
>> +	.result = ACCEPT,
>>   	.flags = BPF_F_SLEEPABLE,
>>   	.runs = -1,
>>   },
>>
>> -- 
>> 2.47.3
>>
>>