From: Jiri Olsa <olsajiri@gmail.com>
To: Andrii Nakryiko <andrii.nakryiko@gmail.com>
Cc: Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andrii@kernel.org>,
bpf@vger.kernel.org, Martin KaFai Lau <kafai@fb.com>,
Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
John Fastabend <john.fastabend@gmail.com>,
KP Singh <kpsingh@chromium.org>,
Stanislav Fomichev <sdf@google.com>, Hao Luo <haoluo@google.com>,
Peter Zijlstra <peterz@infradead.org>,
"Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Subject: Re: [PATCHv2 bpf-next 6/6] selftests/bpf: Fix get_func_ip offset test for CONFIG_X86_KERNEL_IBT
Date: Tue, 16 Aug 2022 09:00:20 +0200 [thread overview]
Message-ID: <YvtAhPyiWDbTzCdA@krava> (raw)
In-Reply-To: <CAEf4BzbXBsL8zrCDEP-+VsKseEQ1fWTRvUkJtwxX5r8q9hf1OA@mail.gmail.com>
On Mon, Aug 15, 2022 at 08:25:51PM -0700, Andrii Nakryiko wrote:
> On Thu, Aug 11, 2022 at 2:16 AM Jiri Olsa <jolsa@kernel.org> wrote:
> >
> > With CONFIG_X86_KERNEL_IBT enabled the test for kprobe with offset
> > won't work because of the extra endbr instruction.
> >
> > As suggested by Andrii adding CONFIG_X86_KERNEL_IBT detection
> > and using appropriate offset value based on that.
> >
> > Also removing test7 program, because it does the same as test6.
> >
> > Suggested-by: Andrii Nakryiko <andrii@kernel.org>
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > .../bpf/prog_tests/get_func_ip_test.c | 62 +++++++++++++++----
> > .../selftests/bpf/progs/get_func_ip_test.c | 20 +++---
> > 2 files changed, 60 insertions(+), 22 deletions(-)
> >
> > diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
> > index 938dbd4d7c2f..a4dab2fa2258 100644
> > --- a/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
> > +++ b/tools/testing/selftests/bpf/prog_tests/get_func_ip_test.c
> > @@ -2,7 +2,9 @@
> > #include <test_progs.h>
> > #include "get_func_ip_test.skel.h"
> >
> > -void test_get_func_ip_test(void)
> > +static int config_ibt;
> > +
> > +static void test_function_entry(void)
> > {
> > struct get_func_ip_test *skel = NULL;
> > int err, prog_fd;
> > @@ -12,14 +14,6 @@ void test_get_func_ip_test(void)
> > if (!ASSERT_OK_PTR(skel, "get_func_ip_test__open"))
> > return;
> >
> > - /* test6 is x86_64 specifc because of the instruction
> > - * offset, disabling it for all other archs
> > - */
> > -#ifndef __x86_64__
> > - bpf_program__set_autoload(skel->progs.test6, false);
> > - bpf_program__set_autoload(skel->progs.test7, false);
> > -#endif
> > -
> > err = get_func_ip_test__load(skel);
> > if (!ASSERT_OK(err, "get_func_ip_test__load"))
> > goto cleanup;
> > @@ -38,16 +32,62 @@ void test_get_func_ip_test(void)
> >
> > ASSERT_OK(err, "test_run");
> >
> > + config_ibt = skel->bss->config_ibt;
>
> skel->bss->config_ibt isn't actually necessary, you can just check
> skel->kconfig->CONFIG_X86_KERNEL_IBT directly. And you won't need to
> trigger BPF program unnecessary, libbpf will fill out kconfig section
> during object/skeleton load phase.
nice, did not know that ;-) will remove it
>
> > + ASSERT_TRUE(config_ibt == 0 || config_ibt == 1, "config_ibt");
>
> you won't need this anymore
>
> > + printf("%s:config_ibt %d\n", __func__, config_ibt);
>
> and this is just debug leftover
it's intentional to find out quickly what config we are failing on
>
> > +
> > ASSERT_EQ(skel->bss->test1_result, 1, "test1_result");
> > ASSERT_EQ(skel->bss->test2_result, 1, "test2_result");
> > ASSERT_EQ(skel->bss->test3_result, 1, "test3_result");
> > ASSERT_EQ(skel->bss->test4_result, 1, "test4_result");
> > ASSERT_EQ(skel->bss->test5_result, 1, "test5_result");
> > +
>
> [...]
>
> > diff --git a/tools/testing/selftests/bpf/progs/get_func_ip_test.c b/tools/testing/selftests/bpf/progs/get_func_ip_test.c
> > index 6db70757bc8b..cb8e58183d46 100644
> > --- a/tools/testing/selftests/bpf/progs/get_func_ip_test.c
> > +++ b/tools/testing/selftests/bpf/progs/get_func_ip_test.c
> > @@ -2,6 +2,7 @@
> > #include <linux/bpf.h>
> > #include <bpf/bpf_helpers.h>
> > #include <bpf/bpf_tracing.h>
> > +#include <stdbool.h>
> >
> > char _license[] SEC("license") = "GPL";
> >
> > @@ -13,12 +14,19 @@ extern const void bpf_modify_return_test __ksym;
> > extern const void bpf_fentry_test6 __ksym;
> > extern const void bpf_fentry_test7 __ksym;
> >
> > +extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak;
> > +
> > +bool config_ibt;
> > +
> > __u64 test1_result = 0;
> > SEC("fentry/bpf_fentry_test1")
> > int BPF_PROG(test1, int a)
> > {
> > __u64 addr = bpf_get_func_ip(ctx);
> >
> > + /* just to propagate config option value to user space */
> > + config_ibt = CONFIG_X86_KERNEL_IBT;
> > +
>
> as mentioned above, you shouldn't need it, just read
> CONFIG_X86_KERNEL_IBT directly through skeleton
>
> > test1_result = (const void *) addr == &bpf_fentry_test1;
> > return 0;
> > }
> > @@ -64,7 +72,7 @@ int BPF_PROG(test5, int a, int *b, int ret)
> > }
> >
> > __u64 test6_result = 0;
> > -SEC("kprobe/bpf_fentry_test6+0x5")
> > +SEC("?kprobe/")
>
> don't leave / at the end (and I thought that libbpf rejects this,
> isn't that a case?...), just SEC("?kprobe")
yes, will remove
thanks,
jirka
next prev parent reply other threads:[~2022-08-16 8:54 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-08-11 9:15 [PATCHv2 bpf-next 0/6] bpf: Fixes for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-08-11 9:15 ` [PATCHv2 bpf-next 1/6] kprobes: Add new KPROBE_FLAG_ON_FUNC_ENTRY kprobe flag Jiri Olsa
2022-08-15 9:57 ` Peter Zijlstra
2022-08-15 10:10 ` Jiri Olsa
2022-08-15 12:40 ` Peter Zijlstra
2022-08-16 7:01 ` Jiri Olsa
2022-08-30 15:08 ` Jiri Olsa
2022-09-08 8:26 ` Jiri Olsa
2022-09-08 12:01 ` Masami Hiramatsu
2022-08-11 9:15 ` [PATCHv2 bpf-next 2/6] ftrace: Keep the resolved addr in kallsyms_callback Jiri Olsa
2022-08-15 10:13 ` Peter Zijlstra
2022-08-15 10:30 ` Jiri Olsa
2022-08-15 12:45 ` Peter Zijlstra
2022-08-16 7:06 ` Jiri Olsa
2022-09-08 12:35 ` Masami Hiramatsu
2022-09-08 19:41 ` Jiri Olsa
2022-08-11 9:15 ` [PATCHv2 bpf-next 3/6] bpf: Use given function address for trampoline ip arg Jiri Olsa
2022-08-15 10:18 ` Peter Zijlstra
2022-08-15 10:57 ` Jiri Olsa
2022-08-15 12:51 ` Peter Zijlstra
2022-08-17 13:40 ` Jiri Olsa
2022-08-11 9:15 ` [PATCHv2 bpf-next 4/6] bpf: Adjust kprobe_multi entry_ip for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-08-11 9:15 ` [PATCHv2 bpf-next 5/6] bpf: Return value in kprobe get_func_ip only for entry address Jiri Olsa
2022-08-11 9:15 ` [PATCHv2 bpf-next 6/6] selftests/bpf: Fix get_func_ip offset test for CONFIG_X86_KERNEL_IBT Jiri Olsa
2022-08-16 3:25 ` Andrii Nakryiko
2022-08-16 7:00 ` Jiri Olsa [this message]
2022-08-16 10:18 ` Jiri Olsa
2022-08-16 17:28 ` Andrii Nakryiko
2022-08-16 17:19 ` Andrii Nakryiko
2022-08-16 3:27 ` [PATCHv2 bpf-next 0/6] bpf: Fixes " Andrii Nakryiko
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