The vmlinux selftest triggers nanosleep and checks that both kprobe and fentry programs observe the hrtimer enqueue path. After the hrtimer_start_expires_user() conversion [1], nanosleep reaches hrtimer_start_range_ns_user() instead of hrtimer_start_range_ns(). Hard-coding either symbol makes the test fail either on bpf tree or on linux-next [2]. Keep both hook variants as optional BPF programs and enable the pair matching the running kernel before loading the object. This is also a nice example of how to modify a BPF program to work on both older and newer kernel revision. [1] https://lore.kernel.org/all/20260408114952.062400833@kernel.org/ [2] https://github.com/kernel-patches/bpf/actions/runs/25485909958/job/74782902203 Signed-off-by: Ihor Solodrai --- .../selftests/bpf/prog_tests/vmlinux.c | 26 +++++++++++++++++-- .../selftests/bpf/progs/test_vmlinux.c | 22 ++++++++++++++-- 2 files changed, 44 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/prog_tests/vmlinux.c b/tools/testing/selftests/bpf/prog_tests/vmlinux.c index 6fb2217d940b..286feff31488 100644 --- a/tools/testing/selftests/bpf/prog_tests/vmlinux.c +++ b/tools/testing/selftests/bpf/prog_tests/vmlinux.c @@ -14,15 +14,37 @@ static void nsleep() (void)syscall(__NR_nanosleep, &ts, NULL); } +static void enable_hrtimer_progs(struct test_vmlinux *skel) +{ + bool has_user_helper; + + has_user_helper = libbpf_find_vmlinux_btf_id("hrtimer_start_range_ns_user", + BPF_TRACE_FENTRY) > 0; + if (has_user_helper) { + bpf_program__set_autoload(skel->progs.handle__kprobe_user, true); + bpf_program__set_autoload(skel->progs.handle__fentry_user, true); + } else { + bpf_program__set_autoload(skel->progs.handle__kprobe, true); + bpf_program__set_autoload(skel->progs.handle__fentry, true); + } +} + void test_vmlinux(void) { int err; struct test_vmlinux* skel; struct test_vmlinux__bss *bss; - skel = test_vmlinux__open_and_load(); - if (!ASSERT_OK_PTR(skel, "test_vmlinux__open_and_load")) + skel = test_vmlinux__open(); + if (!ASSERT_OK_PTR(skel, "test_vmlinux__open")) return; + + enable_hrtimer_progs(skel); + + err = test_vmlinux__load(skel); + if (!ASSERT_OK(err, "test_vmlinux__load")) + goto cleanup; + bss = skel->bss; err = test_vmlinux__attach(skel); diff --git a/tools/testing/selftests/bpf/progs/test_vmlinux.c b/tools/testing/selftests/bpf/progs/test_vmlinux.c index 78b23934d9f8..c90f7ac63f91 100644 --- a/tools/testing/selftests/bpf/progs/test_vmlinux.c +++ b/tools/testing/selftests/bpf/progs/test_vmlinux.c @@ -69,7 +69,7 @@ int BPF_PROG(handle__tp_btf, struct pt_regs *regs, long id) return 0; } -SEC("kprobe/hrtimer_start_range_ns") +SEC("?kprobe/hrtimer_start_range_ns") int BPF_KPROBE(handle__kprobe, struct hrtimer *timer, ktime_t tim, u64 delta_ns, const enum hrtimer_mode mode) { @@ -78,7 +78,7 @@ int BPF_KPROBE(handle__kprobe, struct hrtimer *timer, ktime_t tim, u64 delta_ns, return 0; } -SEC("fentry/hrtimer_start_range_ns") +SEC("?fentry/hrtimer_start_range_ns") int BPF_PROG(handle__fentry, struct hrtimer *timer, ktime_t tim, u64 delta_ns, const enum hrtimer_mode mode) { @@ -87,4 +87,22 @@ int BPF_PROG(handle__fentry, struct hrtimer *timer, ktime_t tim, u64 delta_ns, return 0; } +SEC("?kprobe/hrtimer_start_range_ns_user") +int BPF_KPROBE(handle__kprobe_user, struct hrtimer *timer, ktime_t tim, + u64 delta_ns, const enum hrtimer_mode mode) +{ + if (tim == MY_TV_NSEC) + kprobe_called = true; + return 0; +} + +SEC("?fentry/hrtimer_start_range_ns_user") +int BPF_PROG(handle__fentry_user, struct hrtimer *timer, ktime_t tim, + u64 delta_ns, const enum hrtimer_mode mode) +{ + if (tim == MY_TV_NSEC) + fentry_called = true; + return 0; +} + char _license[] SEC("license") = "GPL"; -- 2.54.0