On Sat, Aug 5, 2023 at 12:22 AM Yonghong Song <yonghong.song@xxxxxxxxx> wrote:
>
>
>
> On 8/4/23 3:57 AM, Yafang Shao wrote:
> > Add selftest for the fill_link_info of uprobe, kprobe and tracepoint.
> > The result:
> >
> > $ tools/testing/selftests/bpf/test_progs --name=fill_link_info
> > #79/1 fill_link_info/kprobe_link_info:OK
> > #79/2 fill_link_info/kretprobe_link_info:OK
> > #79/3 fill_link_info/kprobe_fill_invalid_user_buff:OK
> > #79/4 fill_link_info/tracepoint_link_info:OK
> > #79/5 fill_link_info/uprobe_link_info:OK
> > #79/6 fill_link_info/uretprobe_link_info:OK
> > #79/7 fill_link_info/kprobe_multi_link_info:OK
> > #79/8 fill_link_info/kretprobe_multi_link_info:OK
> > #79/9 fill_link_info/kprobe_multi_ubuff:OK
> > #79 fill_link_info:OK
> > Summary: 1/9 PASSED, 0 SKIPPED, 0 FAILED
> >
> > The test case for kprobe_multi won't be run on aarch64, as it is not
> > supported.
> >
> > Signed-off-by: Yafang Shao <laoar.shao@xxxxxxxxx>
>
> Ack with a few nits below.
>
> Acked-by: Yonghong Song <yonghong.song@xxxxxxxxx>
>
> > ---
> > tools/testing/selftests/bpf/DENYLIST.aarch64 | 3 +
> > .../selftests/bpf/prog_tests/fill_link_info.c | 337 +++++++++++++++++++++
> > .../selftests/bpf/progs/test_fill_link_info.c | 42 +++
> > 3 files changed, 382 insertions(+)
> > create mode 100644 tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> > create mode 100644 tools/testing/selftests/bpf/progs/test_fill_link_info.c
> >
> > diff --git a/tools/testing/selftests/bpf/DENYLIST.aarch64 b/tools/testing/selftests/bpf/DENYLIST.aarch64
> > index 3b61e8b..b2f46b6 100644
> > --- a/tools/testing/selftests/bpf/DENYLIST.aarch64
> > +++ b/tools/testing/selftests/bpf/DENYLIST.aarch64
> > @@ -12,3 +12,6 @@ kprobe_multi_test/skel_api # libbpf: failed to load BPF sk
> > module_attach # prog 'kprobe_multi': failed to auto-attach: -95
> > fentry_test/fentry_many_args # fentry_many_args:FAIL:fentry_many_args_attach unexpected error: -524
> > fexit_test/fexit_many_args # fexit_many_args:FAIL:fexit_many_args_attach unexpected error: -524
> > +fill_link_info/kprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> > +fill_link_info/kretprobe_multi_link_info # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> > +fill_link_info/kprobe_multi_ubuff # bpf_program__attach_kprobe_multi_opts unexpected error: -95
> > diff --git a/tools/testing/selftests/bpf/prog_tests/fill_link_info.c b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> > new file mode 100644
> > index 0000000..001a8b5
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> > @@ -0,0 +1,337 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (C) 2023 Yafang Shao <laoar.shao@xxxxxxxxx> */
> > +
> > +#include <string.h>
> > +#include <linux/bpf.h>
> > +#include <linux/limits.h>
> > +#include <test_progs.h>
> > +#include "trace_helpers.h"
> > +#include "test_fill_link_info.skel.h"
> > +
> > +#define TP_CAT "sched"
> > +#define TP_NAME "sched_switch"
> > +#define KPROBE_FUNC "tcp_rcv_established"
> > +#define UPROBE_FILE "/proc/self/exe"
> > +#define KMULTI_CNT (4)
> > +
> > +/* uprobe attach point */
> > +static noinline void uprobe_func(void)
> > +{
> > + asm volatile ("");
> > +}
> > +
> > +static int verify_perf_link_info(int fd, enum bpf_perf_event_type type, long addr,
> > + ssize_t offset, ssize_t entry_offset)
> > +{
> > + struct bpf_link_info info;
> > + __u32 len = sizeof(info);
> > + char buf[PATH_MAX];
> > + int err = 0;
> > +
> > + memset(&info, 0, sizeof(info));
> > + buf[0] = '\0';
> > +
> > +again:
> > + err = bpf_link_get_info_by_fd(fd, &info, &len);
> > + if (!ASSERT_OK(err, "get_link_info"))
> > + return -1;
> > +
> > + if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT, "link_type"))
> > + return -1;
> > + if (!ASSERT_EQ(info.perf_event.type, type, "perf_type_match"))
> > + return -1;
> > +
> > + switch (info.perf_event.type) {
> > + case BPF_PERF_EVENT_KPROBE:
> > + case BPF_PERF_EVENT_KRETPROBE:
> > + ASSERT_EQ(info.perf_event.kprobe.offset, offset, "kprobe_offset");
> > +
> > + /* In case kernel.kptr_restrict is not permitted or MAX_SYMS is reached */
> > + if (addr)
> > + ASSERT_EQ(info.perf_event.kprobe.addr, addr + entry_offset,
> > + "kprobe_addr");
> > +
> > + if (!info.perf_event.kprobe.func_name) {
> > + ASSERT_EQ(info.perf_event.kprobe.name_len, 0, "name_len");
> > + info.perf_event.kprobe.func_name = ptr_to_u64(&buf);
> > + info.perf_event.kprobe.name_len = sizeof(buf);
> > + goto again;
> > + }
> > +
> > + err = strncmp(u64_to_ptr(info.perf_event.kprobe.func_name), KPROBE_FUNC,
> > + strlen(KPROBE_FUNC));
> > + ASSERT_EQ(err, 0, "cmp_kprobe_func_name");
> > + break;
> > + case BPF_PERF_EVENT_TRACEPOINT:
> > + if (!info.perf_event.tracepoint.tp_name) {
> > + ASSERT_EQ(info.perf_event.tracepoint.name_len, 0, "name_len");
> > + info.perf_event.tracepoint.tp_name = ptr_to_u64(&buf);
> > + info.perf_event.tracepoint.name_len = sizeof(buf);
> > + goto again;
> > + }
> > +
> > + err = strncmp(u64_to_ptr(info.perf_event.tracepoint.tp_name), TP_NAME,
> > + strlen(TP_NAME));
> > + ASSERT_EQ(err, 0, "cmp_tp_name");
> > + break;
> > + case BPF_PERF_EVENT_UPROBE:
> > + case BPF_PERF_EVENT_URETPROBE:
> > + ASSERT_EQ(info.perf_event.uprobe.offset, offset, "uprobe_offset");
> > +
> > + if (!info.perf_event.uprobe.file_name) {
> > + ASSERT_EQ(info.perf_event.uprobe.name_len, 0, "name_len");
> > + info.perf_event.uprobe.file_name = ptr_to_u64(&buf);
> > + info.perf_event.uprobe.name_len = sizeof(buf);
> > + goto again;
> > + }
> > +
> > + err = strncmp(u64_to_ptr(info.perf_event.uprobe.file_name), UPROBE_FILE,
> > + strlen(UPROBE_FILE));
> > + ASSERT_EQ(err, 0, "cmp_file_name");
> > + break;
> > + default:
>
> Is the 'default' case possible? Probably not, right? Then
> let us add
> err = -1;
> to indicate this path is not possible.
will add it.
>
> > + break;
> > + }
> > + return err;
> > +}
> > +
> [...]
> > +
> > +static void test_kprobe_fill_link_info(struct test_fill_link_info *skel,
> > + enum bpf_perf_event_type type,
> > + bool retprobe, bool invalid)
> > +{
> > + DECLARE_LIBBPF_OPTS(bpf_kprobe_opts, opts,
> > + .attach_mode = PROBE_ATTACH_MODE_LINK,
> > + .retprobe = retprobe,
> > + );
> > + ssize_t offset = 0, entry_offset = 0;
>
> Remove 'offset = 0'.
>
> > + int link_fd, err;
> > + long addr;
> > +
> > + skel->links.kprobe_run = bpf_program__attach_kprobe_opts(skel->progs.kprobe_run,
> > + KPROBE_FUNC, &opts);
> > + if (!ASSERT_OK_PTR(skel->links.kprobe_run, "attach_kprobe"))
> > + return;
> > +
> > + link_fd = bpf_link__fd(skel->links.kprobe_run);
> > + addr = ksym_get_addr(KPROBE_FUNC);
> > + if (!invalid) {
> > + /* See also arch_adjust_kprobe_addr(). */
> > + if (skel->kconfig->CONFIG_X86_KERNEL_IBT)
> > + entry_offset = 4;
> > + err = verify_perf_link_info(link_fd, type, addr, offset, entry_offset);
>
> Replease 'offset' with '0'.
will do it.
>
> > + ASSERT_OK(err, "verify_perf_link_info");
> > + } else {
> > + kprobe_fill_invalid_user_buffer(link_fd);
> > + }
> > + bpf_link__detach(skel->links.kprobe_run);
> > +}
> > +
> [...]
> > +
> > +static void test_kprobe_multi_fill_link_info(struct test_fill_link_info *skel,
> > + bool retprobe, bool buffer)
> > +{
> > + LIBBPF_OPTS(bpf_kprobe_multi_opts, opts);
> > + const char *syms[KMULTI_CNT] = {
> > + "schedule_timeout_interruptible",
> > + "schedule_timeout_uninterruptible",
> > + "schedule_timeout_idle",
> > + "schedule_timeout_killable",
> > + };
> > + __u64 addrs[KMULTI_CNT];
> > + int link_fd, i, err = 0;
>
> 'err = 0' => 'err'.
will change it.
>
> > +
> > + qsort(syms, KMULTI_CNT, sizeof(syms[0]), symbols_cmp_r);
> > + opts.syms = syms;
> > + opts.cnt = KMULTI_CNT;
> > + opts.retprobe = retprobe;
> > + skel->links.kmulti_run = bpf_program__attach_kprobe_multi_opts(skel->progs.kmulti_run,
> > + NULL, &opts);
> > + if (!ASSERT_OK_PTR(skel->links.kmulti_run, "attach_kprobe_multi"))
> > + return;
> > +
> > + link_fd = bpf_link__fd(skel->links.kmulti_run);
> > + for (i = 0; i < KMULTI_CNT; i++)
> > + addrs[i] = ksym_get_addr(syms[i]);
> > +
> > + if (!buffer)
> > + err = verify_kmulti_link_info(link_fd, addrs, retprobe);
> > + else
> > + verify_kmulti_user_buffer(link_fd, addrs);
> > + ASSERT_OK(err, "verify_kmulti_link_info");
>
> if (!buffer) {
> err = verify_kmulti_link_info(link_fd, addrs, retprobe);
> ASSERT_OK(err, "verify_kmulti_link_info");
> } else {
> verify_kmulti_user_buffer(link_fd, addrs);
> }
That is better. Thanks for your review.
--
Regards
Yafang
