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Date: Sat, 6 Jul 2019 17:48:36 +0000
From: Yonghong Song <yhs@...com>
To: Andrii Nakryiko <andrii.nakryiko@...il.com>
CC: Andrii Nakryiko <andriin@...com>,
"bpf@...r.kernel.org" <bpf@...r.kernel.org>,
"netdev@...r.kernel.org" <netdev@...r.kernel.org>,
Alexei Starovoitov <ast@...com>,
"daniel@...earbox.net" <daniel@...earbox.net>,
Kernel Team <Kernel-team@...com>
Subject: Re: [PATCH v5 bpf-next 8/9] selftests/bpf: add kprobe/uprobe
selftests
On 7/6/19 10:42 AM, Andrii Nakryiko wrote:
> On Sat, Jul 6, 2019 at 10:21 AM Yonghong Song <yhs@...com> wrote:
>>
>>
>>
>> On 7/1/19 4:59 PM, Andrii Nakryiko wrote:
>>> Add tests verifying kprobe/kretprobe/uprobe/uretprobe APIs work as
>>> expected.
>>>
>>> Signed-off-by: Andrii Nakryiko <andriin@...com>
>>> Reviewed-by: Stanislav Fomichev <sdf@...gle.com>
>>> Acked-by: Song Liu <songliubraving@...com>
>>> ---
>>> .../selftests/bpf/prog_tests/attach_probe.c | 166 ++++++++++++++++++
>>> .../selftests/bpf/progs/test_attach_probe.c | 55 ++++++
>>> 2 files changed, 221 insertions(+)
>>> create mode 100644 tools/testing/selftests/bpf/prog_tests/attach_probe.c
>>> create mode 100644 tools/testing/selftests/bpf/progs/test_attach_probe.c
>>>
>>> diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
>>> new file mode 100644
>>> index 000000000000..a4686395522c
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
>>> @@ -0,0 +1,166 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +#include <test_progs.h>
>>> +
>>> +ssize_t get_base_addr() {
>>> + size_t start;
>>> + char buf[256];
>>> + FILE *f;
>>> +
>>> + f = fopen("/proc/self/maps", "r");
>>> + if (!f)
>>> + return -errno;
>>> +
>>> + while (fscanf(f, "%zx-%*x %s %*s\n", &start, buf) == 2) {
>>> + if (strcmp(buf, "r-xp") == 0) {
>>> + fclose(f);
>>> + return start;
>>> + }
>>> + }
>>> +
>>> + fclose(f);
>>> + return -EINVAL;
>>> +}
>>> +
>>> +#ifdef __x86_64__
>>> +#define SYS_KPROBE_NAME "__x64_sys_nanosleep"
>>> +#else
>>> +#define SYS_KPROBE_NAME "sys_nanosleep"
>>> +#endif
>>> +
>>> +void test_attach_probe(void)
>>> +{
>>> + const char *kprobe_name = "kprobe/sys_nanosleep";
>>> + const char *kretprobe_name = "kretprobe/sys_nanosleep";
>>> + const char *uprobe_name = "uprobe/trigger_func";
>>> + const char *uretprobe_name = "uretprobe/trigger_func";
>>> + const int kprobe_idx = 0, kretprobe_idx = 1;
>>> + const int uprobe_idx = 2, uretprobe_idx = 3;
>>> + const char *file = "./test_attach_probe.o";
>>> + struct bpf_program *kprobe_prog, *kretprobe_prog;
>>> + struct bpf_program *uprobe_prog, *uretprobe_prog;
>>> + struct bpf_object *obj;
>>> + int err, prog_fd, duration = 0, res;
>>> + struct bpf_link *kprobe_link = NULL;
>>> + struct bpf_link *kretprobe_link = NULL;
>>> + struct bpf_link *uprobe_link = NULL;
>>> + struct bpf_link *uretprobe_link = NULL;
>>> + int results_map_fd;
>>> + size_t uprobe_offset;
>>> + ssize_t base_addr;
>>> +
>>> + base_addr = get_base_addr();
>>> + if (CHECK(base_addr < 0, "get_base_addr",
>>> + "failed to find base addr: %zd", base_addr))
>>> + return;
>>> + uprobe_offset = (size_t)&get_base_addr - base_addr;
>>> +
>>> + /* load programs */
>>> + err = bpf_prog_load(file, BPF_PROG_TYPE_KPROBE, &obj, &prog_fd);
>>> + if (CHECK(err, "obj_load", "err %d errno %d\n", err, errno))
>>> + return;
>>> +
>>> + kprobe_prog = bpf_object__find_program_by_title(obj, kprobe_name);
>>> + if (CHECK(!kprobe_prog, "find_probe",
>>> + "prog '%s' not found\n", kprobe_name))
>>> + goto cleanup;
>>> + kretprobe_prog = bpf_object__find_program_by_title(obj, kretprobe_name);
>>> + if (CHECK(!kretprobe_prog, "find_probe",
>>> + "prog '%s' not found\n", kretprobe_name))
>>> + goto cleanup;
>>> + uprobe_prog = bpf_object__find_program_by_title(obj, uprobe_name);
>>> + if (CHECK(!uprobe_prog, "find_probe",
>>> + "prog '%s' not found\n", uprobe_name))
>>> + goto cleanup;
>>> + uretprobe_prog = bpf_object__find_program_by_title(obj, uretprobe_name);
>>> + if (CHECK(!uretprobe_prog, "find_probe",
>>> + "prog '%s' not found\n", uretprobe_name))
>>> + goto cleanup;
>>> +
>>> + /* load maps */
>>> + results_map_fd = bpf_find_map(__func__, obj, "results_map");
>>> + if (CHECK(results_map_fd < 0, "find_results_map",
>>> + "err %d\n", results_map_fd))
>>> + goto cleanup;
>>> +
>>> + kprobe_link = bpf_program__attach_kprobe(kprobe_prog,
>>> + false /* retprobe */,
>>> + SYS_KPROBE_NAME);
>>> + if (CHECK(IS_ERR(kprobe_link), "attach_kprobe",
>>> + "err %ld\n", PTR_ERR(kprobe_link))) {
>>> + kprobe_link = NULL;
>>> + goto cleanup;
>>> + }
>>> + kretprobe_link = bpf_program__attach_kprobe(kretprobe_prog,
>>> + true /* retprobe */,
>>> + SYS_KPROBE_NAME);
>>> + if (CHECK(IS_ERR(kretprobe_link), "attach_kretprobe",
>>> + "err %ld\n", PTR_ERR(kretprobe_link))) {
>>> + kretprobe_link = NULL;
>>> + goto cleanup;
>>> + }
>>> + uprobe_link = bpf_program__attach_uprobe(uprobe_prog,
>>> + false /* retprobe */,
>>> + 0 /* self pid */,
>>> + "/proc/self/exe",
>>> + uprobe_offset);
>>> + if (CHECK(IS_ERR(uprobe_link), "attach_uprobe",
>>> + "err %ld\n", PTR_ERR(uprobe_link))) {
>>> + uprobe_link = NULL;
>>> + goto cleanup;
>>> + }
>>> + uretprobe_link = bpf_program__attach_uprobe(uretprobe_prog,
>>> + true /* retprobe */,
>>> + -1 /* any pid */,
>>> + "/proc/self/exe",
>>> + uprobe_offset);
>>> + if (CHECK(IS_ERR(uretprobe_link), "attach_uretprobe",
>>> + "err %ld\n", PTR_ERR(uretprobe_link))) {
>>> + uretprobe_link = NULL;
>>> + goto cleanup;
>>> + }
>>> +
>>> + /* trigger & validate kprobe && kretprobe */
>>> + usleep(1);
>>> +
>>> + err = bpf_map_lookup_elem(results_map_fd, &kprobe_idx, &res);
>>> + if (CHECK(err, "get_kprobe_res",
>>> + "failed to get kprobe res: %d\n", err))
>>> + goto cleanup;
>>> + if (CHECK(res != kprobe_idx + 1, "check_kprobe_res",
>>> + "wrong kprobe res: %d\n", res))
>>> + goto cleanup;
>>> +
>>> + err = bpf_map_lookup_elem(results_map_fd, &kretprobe_idx, &res);
>>> + if (CHECK(err, "get_kretprobe_res",
>>> + "failed to get kretprobe res: %d\n", err))
>>> + goto cleanup;
>>> + if (CHECK(res != kretprobe_idx + 1, "check_kretprobe_res",
>>> + "wrong kretprobe res: %d\n", res))
>>> + goto cleanup;
>>> +
>>> + /* trigger & validate uprobe & uretprobe */
>>> + get_base_addr();
>>> +
>>> + err = bpf_map_lookup_elem(results_map_fd, &uprobe_idx, &res);
>>> + if (CHECK(err, "get_uprobe_res",
>>> + "failed to get uprobe res: %d\n", err))
>>> + goto cleanup;
>>> + if (CHECK(res != uprobe_idx + 1, "check_uprobe_res",
>>> + "wrong uprobe res: %d\n", res))
>>> + goto cleanup;
>>> +
>>> + err = bpf_map_lookup_elem(results_map_fd, &uretprobe_idx, &res);
>>> + if (CHECK(err, "get_uretprobe_res",
>>> + "failed to get uretprobe res: %d\n", err))
>>> + goto cleanup;
>>> + if (CHECK(res != uretprobe_idx + 1, "check_uretprobe_res",
>>> + "wrong uretprobe res: %d\n", res))
>>> + goto cleanup;
>>> +
>>> +cleanup:
>>> + bpf_link__destroy(kprobe_link);
>>> + bpf_link__destroy(kretprobe_link);
>>> + bpf_link__destroy(uprobe_link);
>>> + bpf_link__destroy(uretprobe_link);
>>> + bpf_object__close(obj);
>>> +}
>>> diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
>>> new file mode 100644
>>> index 000000000000..7a7c5cd728c8
>>> --- /dev/null
>>> +++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
>>> @@ -0,0 +1,55 @@
>>> +// SPDX-License-Identifier: GPL-2.0
>>> +// Copyright (c) 2017 Facebook
>>> +
>>> +#include <linux/ptrace.h>
>>> +#include <linux/bpf.h>
>>> +#include "bpf_helpers.h"
>>> +
>>> +struct {
>>> + int type;
>>> + int max_entries;
>>> + int *key;
>>> + int *value;
>>> +} results_map SEC(".maps") = {
>>> + .type = BPF_MAP_TYPE_ARRAY,
>>> + .max_entries = 4,
>>> +};
>>
>> After the new .maps convention patch is merged, test_progs is broken due
>> to this. The above .maps definition needs to be updated to
>>
>> struct {
>> __uint(type, BPF_MAP_TYPE_ARRAY);
>> __uint(max_entries, 4);
>> __type(key, int);
>> __type(value, int);
>> } results_map SEC(".maps");
>>
>
> Yep, noticed that yesterday. Fixed in [0].
>
> [0] https://urldefense.proofpoint.com/v2/url?u=https-3A__patchwork.ozlabs.org_patch_1128383_&d=DwIBaQ&c=5VD0RTtNlTh3ycd41b3MUw&r=DA8e1B5r073vIqRrFz7MRA&m=HOjHmyyEXoOHq5292pOm6Ai8KJSyeLjdFOHQ_T8oAdI&s=vRc6OsEL3WigbFGNcfJUWeBCPbbyxn8g_r2SeTgoM-I&e=
>
Oh, sorry. forgot this patch. Indeed, it fixed the issue.
>>> +
>>> +SEC("kprobe/sys_nanosleep")
>>> +int handle_sys_nanosleep_entry(struct pt_regs *ctx)
>>> +{
>>> + const int key = 0, value = 1;
>>> +
>>> + bpf_map_update_elem(&results_map, &key, &value, 0);
>>> + return 0;
>>> +}
>>> +
>>> +SEC("kretprobe/sys_nanosleep")
>>> +int handle_sys_getpid_return(struct pt_regs *ctx)
>>> +{
>>> + const int key = 1, value = 2;
>>> +
>>> + bpf_map_update_elem(&results_map, &key, &value, 0);
>>> + return 0;
>>> +}
>>> +
>>> +SEC("uprobe/trigger_func")
>>> +int handle_uprobe_entry(struct pt_regs *ctx)
>>> +{
>>> + const int key = 2, value = 3;
>>> +
>>> + bpf_map_update_elem(&results_map, &key, &value, 0);
>>> + return 0;
>>> +}
>>> +
>>> +SEC("uretprobe/trigger_func")
>>> +int handle_uprobe_return(struct pt_regs *ctx)
>>> +{
>>> + const int key = 3, value = 4;
>>> +
>>> + bpf_map_update_elem(&results_map, &key, &value, 0);
>>> + return 0;
>>> +}
>>> +
>>> +char _license[] SEC("license") = "GPL";
>>> +__u32 _version SEC("version") = 1;
>>>
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