mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-08-09 06:14:34 +02:00
Ihor SolodraiandAlexei Starovoitov
25bb05dd06
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]. Update the test to resolve the target symbol at runtime via libbpf_find_vmlinux_btf_id(). This is 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 <ihor.solodrai@linux.dev> Acked-by: Jiri Olsa <jolsa@kernel.org> Link: https://lore.kernel.org/r/20260509005730.250956-1-ihor.solodrai@linux.dev Signed-off-by: Alexei Starovoitov <ast@kernel.org>
85 lines
2.0 KiB
C
85 lines
2.0 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2020 Facebook */
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#include <test_progs.h>
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#include <time.h>
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#include "test_vmlinux.skel.h"
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#define MY_TV_NSEC 1337
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static void nsleep()
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{
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struct timespec ts = { .tv_nsec = MY_TV_NSEC };
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(void)syscall(__NR_nanosleep, &ts, NULL);
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}
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static const char *hrtimer_func = "hrtimer_start_range_ns";
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static int setup_hrtimer_progs(struct test_vmlinux *skel)
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{
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int err;
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if (libbpf_find_vmlinux_btf_id("hrtimer_start_range_ns_user", BPF_TRACE_FENTRY) > 0)
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hrtimer_func = "hrtimer_start_range_ns_user";
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err = bpf_program__set_attach_target(skel->progs.handle__fentry, 0, hrtimer_func);
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if (err)
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return err;
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/*
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* Bare SEC("kprobe") has no target function, so attach it manually
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* later after selecting the hrtimer function to probe.
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*/
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bpf_program__set_autoattach(skel->progs.handle__kprobe, false);
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return 0;
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}
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void test_vmlinux(void)
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{
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int err;
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struct test_vmlinux* skel;
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struct test_vmlinux__bss *bss;
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struct bpf_link *kprobe_link = NULL;
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skel = test_vmlinux__open();
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if (!ASSERT_OK_PTR(skel, "test_vmlinux__open"))
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return;
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err = setup_hrtimer_progs(skel);
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if (!ASSERT_OK(err, "setup_hrtimer_progs"))
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goto cleanup;
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err = test_vmlinux__load(skel);
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if (!ASSERT_OK(err, "test_vmlinux__load"))
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goto cleanup;
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bss = skel->bss;
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err = test_vmlinux__attach(skel);
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if (!ASSERT_OK(err, "test_vmlinux__attach"))
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goto cleanup;
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/* manually attach kprobe with the selected function */
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if (hrtimer_func) {
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kprobe_link = bpf_program__attach_kprobe(skel->progs.handle__kprobe,
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false /* retprobe */, hrtimer_func);
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if (!ASSERT_OK_PTR(kprobe_link, "bpf_program__attach_kprobe"))
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goto cleanup;
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}
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/* trigger everything */
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nsleep();
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ASSERT_TRUE(bss->tp_called, "tp");
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ASSERT_TRUE(bss->raw_tp_called, "raw_tp");
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ASSERT_TRUE(bss->tp_btf_called, "tp_btf");
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ASSERT_TRUE(bss->kprobe_called, "kprobe");
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ASSERT_TRUE(bss->fentry_called, "fentry");
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cleanup:
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bpf_link__destroy(kprobe_link);
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test_vmlinux__destroy(skel);
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}
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