On Mon, Feb 20, 2023 at 7:40 PM Alan Maguire <alan.maguire@xxxxxxxxxx> wrote:
>
> On 20/02/2023 08:47, menglong8.dong@xxxxxxxxx wrote:
> > From: Menglong Dong <imagedong@xxxxxxxxxxx>
> >
> > In order to adapt to the older kernel, now we split the "attach_probe"
> > testing into multi subtests:
> >
> > manual // manual attach tests for kprobe/uprobe
> > auto // auto-attach tests for kprobe and uprobe
> > kprobe-sleepable // kprobe sleepable test
> > uprobe-lib // uprobe tests for library function by name
> > uprobe-sleepabel // uprobe sleepable test
> > uprobe-ref_ctr // uprobe ref_ctr test
> >
> > As sleepable kprobe needs to set BPF_F_SLEEPABLE flag before loading,
> > we need to move it to a stand alone skel file, in case of it is not
> > supported by kernel and make the whole loading fail.
> >
> > Therefore, we can only enable part of the subtests for older kernel.
> >
> > Signed-off-by: Menglong Dong <imagedong@xxxxxxxxxxx>
>
> this is great work! One small typo in the ref counter subtest function
> name below, but for the series:
>
> Reviewed-by: Alan Maguire <alan.maguire@xxxxxxxxxx>
>
> > ---
> > .../selftests/bpf/prog_tests/attach_probe.c | 268 +++++++++++-------
> > .../bpf/progs/test_attach_kprobe_sleepable.c | 23 ++
> > .../selftests/bpf/progs/test_attach_probe.c | 23 +-
> > 3 files changed, 208 insertions(+), 106 deletions(-)
> > create mode 100644 tools/testing/selftests/bpf/progs/test_attach_kprobe_sleepable.c
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/attach_probe.c b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > index 56374c8b5436..9824a5eb8595 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/attach_probe.c
> > @@ -1,5 +1,6 @@
> > // SPDX-License-Identifier: GPL-2.0
> > #include <test_progs.h>
> > +#include "test_attach_kprobe_sleepable.skel.h"
> > #include "test_attach_probe.skel.h"
> >
> > /* this is how USDT semaphore is actually defined, except volatile modifier */
> > @@ -23,110 +24,63 @@ static noinline void trigger_func3(void)
> > asm volatile ("");
> > }
> >
> > +/* attach point for ref_ctr */
> > +static noinline void trigger_func4(void)
> > +{
> > + asm volatile ("");
> > +}
> > +
> > static char test_data[] = "test_data";
> >
> > -void test_attach_probe(void)
> > +/* manual attach kprobe/kretprobe/uprobe/uretprobe testings */
> > +static void test_attach_probe_manual(struct test_attach_probe *skel)
> > {
> > DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
> > struct bpf_link *kprobe_link, *kretprobe_link;
> > struct bpf_link *uprobe_link, *uretprobe_link;
> > - struct test_attach_probe* skel;
> > - ssize_t uprobe_offset, ref_ctr_offset;
> > - struct bpf_link *uprobe_err_link;
> > - FILE *devnull;
> > - bool legacy;
> > -
> > - /* Check if new-style kprobe/uprobe API is supported.
> > - * Kernels that support new FD-based kprobe and uprobe BPF attachment
> > - * through perf_event_open() syscall expose
> > - * /sys/bus/event_source/devices/kprobe/type and
> > - * /sys/bus/event_source/devices/uprobe/type files, respectively. They
> > - * contain magic numbers that are passed as "type" field of
> > - * perf_event_attr. Lack of such file in the system indicates legacy
> > - * kernel with old-style kprobe/uprobe attach interface through
> > - * creating per-probe event through tracefs. For such cases
> > - * ref_ctr_offset feature is not supported, so we don't test it.
> > - */
> > - legacy = access("/sys/bus/event_source/devices/kprobe/type", F_OK) != 0;
> > + ssize_t uprobe_offset;
> >
> > uprobe_offset = get_uprobe_offset(&trigger_func);
> > if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset"))
> > return;
> >
> > - ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
> > - if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
> > - return;
> > -
> > - skel = test_attach_probe__open();
> > - if (!ASSERT_OK_PTR(skel, "skel_open"))
> > - return;
> > -
> > - /* sleepable kprobe test case needs flags set before loading */
> > - if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable,
> > - BPF_F_SLEEPABLE), "kprobe_sleepable_flags"))
> > - goto cleanup;
> > -
> > - if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load"))
> > - goto cleanup;
> > - if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
> > - goto cleanup;
> > -
> > /* manual-attach kprobe/kretprobe */
> > kprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kprobe,
> > false /* retprobe */,
> > SYS_NANOSLEEP_KPROBE_NAME);
> > if (!ASSERT_OK_PTR(kprobe_link, "attach_kprobe"))
> > - goto cleanup;
> > + return;
> > skel->links.handle_kprobe = kprobe_link;
> >
> > kretprobe_link = bpf_program__attach_kprobe(skel->progs.handle_kretprobe,
> > true /* retprobe */,
> > SYS_NANOSLEEP_KPROBE_NAME);
> > if (!ASSERT_OK_PTR(kretprobe_link, "attach_kretprobe"))
> > - goto cleanup;
> > + return;
> > skel->links.handle_kretprobe = kretprobe_link;
> >
> > - /* auto-attachable kprobe and kretprobe */
> > - skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto);
> > - ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto");
> > -
> > - skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto);
> > - ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto");
> > -
> > - if (!legacy)
> > - ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before");
> > -
> > + /* manual-attach uprobe/uretprobe */
> > + uprobe_opts.ref_ctr_offset = 0;
> > uprobe_opts.retprobe = false;
> > - uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
> > uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe,
> > 0 /* self pid */,
> > "/proc/self/exe",
> > uprobe_offset,
> > &uprobe_opts);
> > if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe"))
> > - goto cleanup;
> > + return;
> > skel->links.handle_uprobe = uprobe_link;
> >
> > - if (!legacy)
> > - ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after");
> > -
> > - /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */
> > uprobe_opts.retprobe = true;
> > - uprobe_opts.ref_ctr_offset = legacy ? 0 : ref_ctr_offset;
> > uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe,
> > -1 /* any pid */,
> > "/proc/self/exe",
> > uprobe_offset, &uprobe_opts);
> > if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe"))
> > - goto cleanup;
> > + return;
> > skel->links.handle_uretprobe = uretprobe_link;
> >
> > - /* verify auto-attach fails for old-style uprobe definition */
> > - uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);
> > - if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,
> > - "auto-attach should fail for old-style name"))
> > - goto cleanup;
> > -
> > + /* attach uprobe by function name manually */
> > uprobe_opts.func_name = "trigger_func2";
> > uprobe_opts.retprobe = false;
> > uprobe_opts.ref_ctr_offset = 0;
> > @@ -136,13 +90,62 @@ void test_attach_probe(void)
> > "/proc/self/exe",
> > 0, &uprobe_opts);
> > if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname, "attach_uprobe_byname"))
> > - goto cleanup;
> > + return;
> > +
> > + /* trigger & validate kprobe && kretprobe */
> > + usleep(1);
> > +
> > + /* trigger & validate uprobe & uretprobe */
> > + trigger_func();
> > +
> > + /* trigger & validate uprobe attached by name */
> > + trigger_func2();
> > +
> > + ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
> > + ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
> > + ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");
> > + ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");
> > + ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");
> > +}
> > +
> > +static void test_attach_probe_auto(struct test_attach_probe *skel)
> > +{
> > + struct bpf_link *uprobe_err_link;
> > +
> > + /* auto-attachable kprobe and kretprobe */
> > + skel->links.handle_kprobe_auto = bpf_program__attach(skel->progs.handle_kprobe_auto);
> > + ASSERT_OK_PTR(skel->links.handle_kprobe_auto, "attach_kprobe_auto");
> > +
> > + skel->links.handle_kretprobe_auto = bpf_program__attach(skel->progs.handle_kretprobe_auto);
> > + ASSERT_OK_PTR(skel->links.handle_kretprobe_auto, "attach_kretprobe_auto");
> > +
> > + /* verify auto-attach fails for old-style uprobe definition */
> > + uprobe_err_link = bpf_program__attach(skel->progs.handle_uprobe_byname);
> > + if (!ASSERT_EQ(libbpf_get_error(uprobe_err_link), -EOPNOTSUPP,
> > + "auto-attach should fail for old-style name"))
> > + return;
> >
> > /* verify auto-attach works */
> > skel->links.handle_uretprobe_byname =
> > bpf_program__attach(skel->progs.handle_uretprobe_byname);
> > if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname, "attach_uretprobe_byname"))
> > - goto cleanup;
> > + return;
> > +
> > + /* trigger & validate kprobe && kretprobe */
> > + usleep(1);
> > +
> > + /* trigger & validate uprobe attached by name */
> > + trigger_func2();
> > +
> > + ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res");
> > + ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res");
> > + ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");
> > +}
> > +
> > +static void test_uprobe_lib(struct test_attach_probe *skel)
> > +{
> > + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
> > + FILE *devnull;
> >
> > /* test attach by name for a library function, using the library
> > * as the binary argument. libc.so.6 will be resolved via dlopen()/dlinfo().
> > @@ -155,7 +158,7 @@ void test_attach_probe(void)
> > "libc.so.6",
> > 0, &uprobe_opts);
> > if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname2, "attach_uprobe_byname2"))
> > - goto cleanup;
> > + return;
> >
> > uprobe_opts.func_name = "fclose";
> > uprobe_opts.retprobe = true;
> > @@ -165,62 +168,137 @@ void test_attach_probe(void)
> > "libc.so.6",
> > 0, &uprobe_opts);
> > if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname2, "attach_uretprobe_byname2"))
> > + return;
> > +
> > + /* trigger & validate shared library u[ret]probes attached by name */
> > + devnull = fopen("/dev/null", "r");
> > + fclose(devnull);
> > +
> > + ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");
> > + ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");
> > +}
> > +
> > +static void test_uporbe_ref_ctr(struct test_attach_probe *skel)
>
> typo, should be test_uprobe_ref_ctr
>
Oops......Thanks! I'll send the v3 with your viewed-by tag and
fix the typo.
Thanks!
Menglong Dong
> > +{
> > + DECLARE_LIBBPF_OPTS(bpf_uprobe_opts, uprobe_opts);
> > + struct bpf_link *uprobe_link, *uretprobe_link;
> > + ssize_t uprobe_offset, ref_ctr_offset;
> > +
> > + uprobe_offset = get_uprobe_offset(&trigger_func4);
> > + if (!ASSERT_GE(uprobe_offset, 0, "uprobe_offset_ref_ctr"))
> > + return;
> > +
> > + ref_ctr_offset = get_rel_offset((uintptr_t)&uprobe_ref_ctr);
> > + if (!ASSERT_GE(ref_ctr_offset, 0, "ref_ctr_offset"))
> > + return;
> > +
> > + ASSERT_EQ(uprobe_ref_ctr, 0, "uprobe_ref_ctr_before");
> > +
> > + uprobe_opts.retprobe = false;
> > + uprobe_opts.ref_ctr_offset = ref_ctr_offset;
> > + uprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uprobe_ref_ctr,
> > + 0 /* self pid */,
> > + "/proc/self/exe",
> > + uprobe_offset,
> > + &uprobe_opts);
> > + if (!ASSERT_OK_PTR(uprobe_link, "attach_uprobe_ref_ctr"))
> > + return;
> > + skel->links.handle_uprobe_ref_ctr = uprobe_link;
> > +
> > + ASSERT_GT(uprobe_ref_ctr, 0, "uprobe_ref_ctr_after");
> > +
> > + /* if uprobe uses ref_ctr, uretprobe has to use ref_ctr as well */
> > + uprobe_opts.retprobe = true;
> > + uprobe_opts.ref_ctr_offset = ref_ctr_offset;
> > + uretprobe_link = bpf_program__attach_uprobe_opts(skel->progs.handle_uretprobe_ref_ctr,
> > + -1 /* any pid */,
> > + "/proc/self/exe",
> > + uprobe_offset, &uprobe_opts);
> > + if (!ASSERT_OK_PTR(uretprobe_link, "attach_uretprobe_ref_ctr"))
> > + return;
> > + skel->links.handle_uretprobe_ref_ctr = uretprobe_link;
> > +}
> > +
> > +static void test_kprobe_sleepable(void)
> > +{
> > + struct test_attach_kprobe_sleepable *skel;
> > +
> > + skel = test_attach_kprobe_sleepable__open();
> > + if (!ASSERT_OK_PTR(skel, "skel_kprobe_sleepable_open"))
> > + return;
> > +
> > + /* sleepable kprobe test case needs flags set before loading */
> > + if (!ASSERT_OK(bpf_program__set_flags(skel->progs.handle_kprobe_sleepable,
> > + BPF_F_SLEEPABLE), "kprobe_sleepable_flags"))
> > + goto cleanup;
> > +
> > + if (!ASSERT_OK(test_attach_kprobe_sleepable__load(skel),
> > + "skel_kprobe_sleepable_load"))
> > goto cleanup;
> >
> > /* sleepable kprobes should not attach successfully */
> > skel->links.handle_kprobe_sleepable = bpf_program__attach(skel->progs.handle_kprobe_sleepable);
> > - if (!ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable"))
> > - goto cleanup;
> > + ASSERT_ERR_PTR(skel->links.handle_kprobe_sleepable, "attach_kprobe_sleepable");
> > +
> > +cleanup:
> > + test_attach_kprobe_sleepable__destroy(skel);
> > +}
> >
> > +static void test_uprobe_sleepable(struct test_attach_probe *skel)
> > +{
> > /* test sleepable uprobe and uretprobe variants */
> > skel->links.handle_uprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uprobe_byname3_sleepable);
> > if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3_sleepable, "attach_uprobe_byname3_sleepable"))
> > - goto cleanup;
> > + return;
> >
> > skel->links.handle_uprobe_byname3 = bpf_program__attach(skel->progs.handle_uprobe_byname3);
> > if (!ASSERT_OK_PTR(skel->links.handle_uprobe_byname3, "attach_uprobe_byname3"))
> > - goto cleanup;
> > + return;
> >
> > skel->links.handle_uretprobe_byname3_sleepable = bpf_program__attach(skel->progs.handle_uretprobe_byname3_sleepable);
> > if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3_sleepable, "attach_uretprobe_byname3_sleepable"))
> > - goto cleanup;
> > + return;
> >
> > skel->links.handle_uretprobe_byname3 = bpf_program__attach(skel->progs.handle_uretprobe_byname3);
> > if (!ASSERT_OK_PTR(skel->links.handle_uretprobe_byname3, "attach_uretprobe_byname3"))
> > - goto cleanup;
> > + return;
> >
> > skel->bss->user_ptr = test_data;
> >
> > - /* trigger & validate kprobe && kretprobe */
> > - usleep(1);
> > -
> > - /* trigger & validate shared library u[ret]probes attached by name */
> > - devnull = fopen("/dev/null", "r");
> > - fclose(devnull);
> > -
> > - /* trigger & validate uprobe & uretprobe */
> > - trigger_func();
> > -
> > - /* trigger & validate uprobe attached by name */
> > - trigger_func2();
> > -
> > /* trigger & validate sleepable uprobe attached by name */
> > trigger_func3();
> >
> > - ASSERT_EQ(skel->bss->kprobe_res, 1, "check_kprobe_res");
> > - ASSERT_EQ(skel->bss->kprobe2_res, 11, "check_kprobe_auto_res");
> > - ASSERT_EQ(skel->bss->kretprobe_res, 2, "check_kretprobe_res");
> > - ASSERT_EQ(skel->bss->kretprobe2_res, 22, "check_kretprobe_auto_res");
> > - ASSERT_EQ(skel->bss->uprobe_res, 3, "check_uprobe_res");
> > - ASSERT_EQ(skel->bss->uretprobe_res, 4, "check_uretprobe_res");
> > - ASSERT_EQ(skel->bss->uprobe_byname_res, 5, "check_uprobe_byname_res");
> > - ASSERT_EQ(skel->bss->uretprobe_byname_res, 6, "check_uretprobe_byname_res");
> > - ASSERT_EQ(skel->bss->uprobe_byname2_res, 7, "check_uprobe_byname2_res");
> > - ASSERT_EQ(skel->bss->uretprobe_byname2_res, 8, "check_uretprobe_byname2_res");
> > ASSERT_EQ(skel->bss->uprobe_byname3_sleepable_res, 9, "check_uprobe_byname3_sleepable_res");
> > ASSERT_EQ(skel->bss->uprobe_byname3_res, 10, "check_uprobe_byname3_res");
> > ASSERT_EQ(skel->bss->uretprobe_byname3_sleepable_res, 11, "check_uretprobe_byname3_sleepable_res");
> > ASSERT_EQ(skel->bss->uretprobe_byname3_res, 12, "check_uretprobe_byname3_res");
> > +}
> > +
> > +void test_attach_probe(void)
> > +{
> > + struct test_attach_probe *skel;
> > +
> > + skel = test_attach_probe__open();
> > + if (!ASSERT_OK_PTR(skel, "skel_open"))
> > + return;
> > +
> > + if (!ASSERT_OK(test_attach_probe__load(skel), "skel_load"))
> > + goto cleanup;
> > + if (!ASSERT_OK_PTR(skel->bss, "check_bss"))
> > + goto cleanup;
> > +
> > + if (test__start_subtest("manual"))
> > + test_attach_probe_manual(skel);
> > + if (test__start_subtest("auto"))
> > + test_attach_probe_auto(skel);
> > + if (test__start_subtest("kprobe-sleepable"))
> > + test_kprobe_sleepable();
> > + if (test__start_subtest("uprobe-lib"))
> > + test_uprobe_lib(skel);
> > + if (test__start_subtest("uprobe-sleepable"))
> > + test_uprobe_sleepable(skel);
> > + if (test__start_subtest("uprobe-ref_ctr"))
> > + test_uporbe_ref_ctr(skel);
>
> ...and here.
>
> >
> > cleanup:
> > test_attach_probe__destroy(skel);
> > diff --git a/tools/testing/selftests/bpf/progs/test_attach_kprobe_sleepable.c b/tools/testing/selftests/bpf/progs/test_attach_kprobe_sleepable.c
> > new file mode 100644
> > index 000000000000..f548b7446218
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/progs/test_attach_kprobe_sleepable.c
> > @@ -0,0 +1,23 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +// Copyright (c) 2017 Facebook
> > +
> > +#include "vmlinux.h"
> > +#include <bpf/bpf_helpers.h>
> > +#include <bpf/bpf_tracing.h>
> > +#include <bpf/bpf_core_read.h>
> > +#include "bpf_misc.h"
> > +
> > +int kprobe_res = 0;
> > +
> > +/**
> > + * This program will be manually made sleepable on the userspace side
> > + * and should thus be unattachable.
> > + */
> > +SEC("kprobe/" SYS_PREFIX "sys_nanosleep")
> > +int handle_kprobe_sleepable(struct pt_regs *ctx)
> > +{
> > + kprobe_res = 1;
> > + return 0;
> > +}
> > +
> > +char _license[] SEC("license") = "GPL";
> > diff --git a/tools/testing/selftests/bpf/progs/test_attach_probe.c b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > index 3b5dc34d23e9..9e1e7163bb67 100644
> > --- a/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > +++ b/tools/testing/selftests/bpf/progs/test_attach_probe.c
> > @@ -37,17 +37,6 @@ int BPF_KSYSCALL(handle_kprobe_auto, struct __kernel_timespec *req, struct __ker
> > return 0;
> > }
> >
> > -/**
> > - * This program will be manually made sleepable on the userspace side
> > - * and should thus be unattachable.
> > - */
> > -SEC("kprobe/" SYS_PREFIX "sys_nanosleep")
> > -int handle_kprobe_sleepable(struct pt_regs *ctx)
> > -{
> > - kprobe_res = 2;
> > - return 0;
> > -}
> > -
> > SEC("kretprobe")
> > int handle_kretprobe(struct pt_regs *ctx)
> > {
> > @@ -76,6 +65,18 @@ int handle_uretprobe(struct pt_regs *ctx)
> > return 0;
> > }
> >
> > +SEC("uprobe")
> > +int handle_uprobe_ref_ctr(struct pt_regs *ctx)
> > +{
> > + return 0;
> > +}
> > +
> > +SEC("uretprobe")
> > +int handle_uretprobe_ref_ctr(struct pt_regs *ctx)
> > +{
> > + return 0;
> > +}
> > +
> > SEC("uprobe")
> > int handle_uprobe_byname(struct pt_regs *ctx)
> > {
> >
