diff mbox series

[bpf-next,3/3] selftests/bpf: Add tests for get_func_[arg|ret|arg_cnt] helpers

Message ID 20211204140700.396138-4-jolsa@kernel.org (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Add helpers to access traced function arguments | expand

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Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/tree_selection success Clearly marked for bpf-next
netdev/fixes_present success Fixes tag not required for -next series
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/cc_maintainers warning 4 maintainers not CCed: shuah@kernel.org andrii@kernel.org linux-kselftest@vger.kernel.org kpsingh@kernel.org
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/module_param success Was 0 now: 0
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netdev/verify_fixes success No Fixes tag
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netdev/checkpatch warning CHECK: No space is necessary after a cast WARNING: From:/Signed-off-by: email address mismatch: 'From: Jiri Olsa <jolsa@redhat.com>' != 'Signed-off-by: Jiri Olsa <jolsa@kernel.org>' WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
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netdev/source_inline success Was 0 now: 0
bpf/vmtest-bpf-next success VM_Test

Commit Message

Jiri Olsa Dec. 4, 2021, 2:07 p.m. UTC 
Adding tests for get_func_[arg|ret|arg_cnt] helpers.
Using these helpers in fentry/fexit/fmod_ret programs.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
---
 .../bpf/prog_tests/get_func_args_test.c       |  38 ++++++
 .../selftests/bpf/progs/get_func_args_test.c  | 112 ++++++++++++++++++
 2 files changed, 150 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
 create mode 100644 tools/testing/selftests/bpf/progs/get_func_args_test.c

Comments

Andrii Nakryiko Dec. 6, 2021, 10:03 p.m. UTC | #1 
On 12/4/21 6:07 AM, Jiri Olsa wrote:
> Adding tests for get_func_[arg|ret|arg_cnt] helpers.
> Using these helpers in fentry/fexit/fmod_ret programs.
>
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>   .../bpf/prog_tests/get_func_args_test.c       |  38 ++++++
>   .../selftests/bpf/progs/get_func_args_test.c  | 112 ++++++++++++++++++
>   2 files changed, 150 insertions(+)
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
>   create mode 100644 tools/testing/selftests/bpf/progs/get_func_args_test.c
>
> diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> new file mode 100644
> index 000000000000..c24807ae4361
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> @@ -0,0 +1,38 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <test_progs.h>
> +#include "get_func_args_test.skel.h"
> +
> +void test_get_func_args_test(void)
> +{
> +	struct get_func_args_test *skel = NULL;
> +	__u32 duration = 0, retval;
> +	int err, prog_fd;
> +
> +	skel = get_func_args_test__open_and_load();
> +	if (!ASSERT_OK_PTR(skel, "get_func_args_test__open_and_load"))
> +		return;
> +
> +	err = get_func_args_test__attach(skel);
> +	if (!ASSERT_OK(err, "get_func_args_test__attach"))
> +		goto cleanup;
> +
> +	prog_fd = bpf_program__fd(skel->progs.test1);
> +	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> +				NULL, NULL, &retval, &duration);
> +	ASSERT_OK(err, "test_run");
> +	ASSERT_EQ(retval, 0, "test_run");
> +
> +	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
> +	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> +				NULL, NULL, &retval, &duration);
> +	ASSERT_OK(err, "test_run");
> +	ASSERT_EQ(retval, 1234, "test_run");


are the other two programs executed implicitly during one of those test 
runs? Can you please leave a small comment somewhere here if that's true?


> +
> +	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");
> +
> +cleanup:
> +	get_func_args_test__destroy(skel);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> new file mode 100644
> index 000000000000..0d0a67c849ae
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> @@ -0,0 +1,112 @@
> +// SPDX-License-Identifier: GPL-2.0
> +#include <linux/bpf.h>
> +#include <bpf/bpf_helpers.h>
> +#include <bpf/bpf_tracing.h>
> +#include <errno.h>
> +
> +char _license[] SEC("license") = "GPL";
> +
> +__u64 test1_result = 0;
> +SEC("fentry/bpf_fentry_test1")
> +int BPF_PROG(test1)
> +{
> +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> +	__u64 a = 0, z = 0, ret = 0;
> +	__s64 err;
> +
> +	test1_result = cnt == 1;
> +
> +	/* valid arguments */
> +	err = bpf_get_func_arg(ctx, 0, &a);
> +	test1_result &= err == 0 && (int) a == 1;


int cast unnecessary? but some ()'s wouldn't hurt...


> +
> +	/* not valid argument */
> +	err = bpf_get_func_arg(ctx, 1, &z);
> +	test1_result &= err == -EINVAL;
> +
> +	/* return value fails in fentry */
> +	err = bpf_get_func_ret(ctx, &ret);
> +	test1_result &= err == -EINVAL;
> +	return 0;
> +}
> +
> +__u64 test2_result = 0;
> +SEC("fexit/bpf_fentry_test2")
> +int BPF_PROG(test2)
> +{
> +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> +	__u64 a = 0, b = 0, z = 0, ret = 0;
> +	__s64 err;
> +
> +	test2_result = cnt == 2;
> +
> +	/* valid arguments */
> +	err = bpf_get_func_arg(ctx, 0, &a);
> +	test2_result &= err == 0 && (int) a == 2;
> +
> +	err = bpf_get_func_arg(ctx, 1, &b);
> +	test2_result &= err == 0 && b == 3;
> +
> +	/* not valid argument */
> +	err = bpf_get_func_arg(ctx, 2, &z);
> +	test2_result &= err == -EINVAL;
> +
> +	/* return value */
> +	err = bpf_get_func_ret(ctx, &ret);
> +	test2_result &= err == 0 && ret == 5;
> +	return 0;
> +}
> +
> +__u64 test3_result = 0;
> +SEC("fmod_ret/bpf_modify_return_test")
> +int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
> +{
> +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> +	__u64 a = 0, b = 0, z = 0, ret = 0;
> +	__s64 err;
> +
> +	test3_result = cnt == 2;
> +
> +	/* valid arguments */
> +	err = bpf_get_func_arg(ctx, 0, &a);
> +	test3_result &= err == 0 && (int) a == 1;
> +
> +	err = bpf_get_func_arg(ctx, 1, &b);
> +	test3_result &= err == 0;


why no checking of b value here?


> +
> +	/* not valid argument */
> +	err = bpf_get_func_arg(ctx, 2, &z);
> +	test3_result &= err == -EINVAL;
> +
> +	/* return value */
> +	err = bpf_get_func_ret(ctx, &ret);
> +	test3_result &= err == 0 && ret == 0;
> +	return 1234;
> +}
> +
> +__u64 test4_result = 0;
> +SEC("fexit/bpf_modify_return_test")
> +int BPF_PROG(fexit_test, int _a, __u64 _b, int _ret)
> +{
> +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> +	__u64 a = 0, b = 0, z = 0, ret = 0;
> +	__s64 err;
> +
> +	test4_result = cnt == 2;
> +
> +	/* valid arguments */
> +	err = bpf_get_func_arg(ctx, 0, &a);
> +	test4_result &= err == 0 && (int) a == 1;
> +
> +	err = bpf_get_func_arg(ctx, 1, &b);
> +	test4_result &= err == 0;


same, for consistency, b should have been checked, no?


> +
> +	/* not valid argument */
> +	err = bpf_get_func_arg(ctx, 2, &z);
> +	test4_result &= err == -EINVAL;
> +
> +	/* return value */
> +	err = bpf_get_func_ret(ctx, &ret);
> +	test4_result &= err == 0 && ret == 1234;
> +	return 0;
> +}
Jiri Olsa Dec. 7, 2021, 6:14 p.m. UTC | #2 
On Mon, Dec 06, 2021 at 02:03:54PM -0800, Andrii Nakryiko wrote:
> 
> On 12/4/21 6:07 AM, Jiri Olsa wrote:
> > Adding tests for get_func_[arg|ret|arg_cnt] helpers.
> > Using these helpers in fentry/fexit/fmod_ret programs.
> > 
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> >   .../bpf/prog_tests/get_func_args_test.c       |  38 ++++++
> >   .../selftests/bpf/progs/get_func_args_test.c  | 112 ++++++++++++++++++
> >   2 files changed, 150 insertions(+)
> >   create mode 100644 tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> >   create mode 100644 tools/testing/selftests/bpf/progs/get_func_args_test.c
> > 
> > diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> > new file mode 100644
> > index 000000000000..c24807ae4361
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> > @@ -0,0 +1,38 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#include <test_progs.h>
> > +#include "get_func_args_test.skel.h"
> > +
> > +void test_get_func_args_test(void)
> > +{
> > +	struct get_func_args_test *skel = NULL;
> > +	__u32 duration = 0, retval;
> > +	int err, prog_fd;
> > +
> > +	skel = get_func_args_test__open_and_load();
> > +	if (!ASSERT_OK_PTR(skel, "get_func_args_test__open_and_load"))
> > +		return;
> > +
> > +	err = get_func_args_test__attach(skel);
> > +	if (!ASSERT_OK(err, "get_func_args_test__attach"))
> > +		goto cleanup;
> > +
> > +	prog_fd = bpf_program__fd(skel->progs.test1);
> > +	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> > +				NULL, NULL, &retval, &duration);
> > +	ASSERT_OK(err, "test_run");
> > +	ASSERT_EQ(retval, 0, "test_run");
> > +
> > +	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
> > +	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> > +				NULL, NULL, &retval, &duration);
> > +	ASSERT_OK(err, "test_run");
> > +	ASSERT_EQ(retval, 1234, "test_run");
> 
> 
> are the other two programs executed implicitly during one of those test
> runs? Can you please leave a small comment somewhere here if that's true?

test1 triggers all the bpf_fentry_test* fentry/fexits
fmod_ret_test triggers the rest, I'll put it in comment

> 
> 
> > +
> > +	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");
> > +
> > +cleanup:
> > +	get_func_args_test__destroy(skel);
> > +}
> > diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> > new file mode 100644
> > index 000000000000..0d0a67c849ae
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> > @@ -0,0 +1,112 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +#include <linux/bpf.h>
> > +#include <bpf/bpf_helpers.h>
> > +#include <bpf/bpf_tracing.h>
> > +#include <errno.h>
> > +
> > +char _license[] SEC("license") = "GPL";
> > +
> > +__u64 test1_result = 0;
> > +SEC("fentry/bpf_fentry_test1")
> > +int BPF_PROG(test1)
> > +{
> > +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> > +	__u64 a = 0, z = 0, ret = 0;
> > +	__s64 err;
> > +
> > +	test1_result = cnt == 1;
> > +
> > +	/* valid arguments */
> > +	err = bpf_get_func_arg(ctx, 0, &a);
> > +	test1_result &= err == 0 && (int) a == 1;
> 
> 
> int cast unnecessary? but some ()'s wouldn't hurt...

it is, 'a' is int and trampoline saves it with 32-bit register like:

  mov    %edi,-0x8(%rbp)

so the upper 4 bytes are not zeroed

> 
> 
> > +
> > +	/* not valid argument */
> > +	err = bpf_get_func_arg(ctx, 1, &z);
> > +	test1_result &= err == -EINVAL;
> > +
> > +	/* return value fails in fentry */
> > +	err = bpf_get_func_ret(ctx, &ret);
> > +	test1_result &= err == -EINVAL;
> > +	return 0;
> > +}
> > +
> > +__u64 test2_result = 0;
> > +SEC("fexit/bpf_fentry_test2")
> > +int BPF_PROG(test2)
> > +{
> > +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> > +	__u64 a = 0, b = 0, z = 0, ret = 0;
> > +	__s64 err;
> > +
> > +	test2_result = cnt == 2;
> > +
> > +	/* valid arguments */
> > +	err = bpf_get_func_arg(ctx, 0, &a);
> > +	test2_result &= err == 0 && (int) a == 2;
> > +
> > +	err = bpf_get_func_arg(ctx, 1, &b);
> > +	test2_result &= err == 0 && b == 3;
> > +
> > +	/* not valid argument */
> > +	err = bpf_get_func_arg(ctx, 2, &z);
> > +	test2_result &= err == -EINVAL;
> > +
> > +	/* return value */
> > +	err = bpf_get_func_ret(ctx, &ret);
> > +	test2_result &= err == 0 && ret == 5;
> > +	return 0;
> > +}
> > +
> > +__u64 test3_result = 0;
> > +SEC("fmod_ret/bpf_modify_return_test")
> > +int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
> > +{
> > +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> > +	__u64 a = 0, b = 0, z = 0, ret = 0;
> > +	__s64 err;
> > +
> > +	test3_result = cnt == 2;
> > +
> > +	/* valid arguments */
> > +	err = bpf_get_func_arg(ctx, 0, &a);
> > +	test3_result &= err == 0 && (int) a == 1;
> > +
> > +	err = bpf_get_func_arg(ctx, 1, &b);
> > +	test3_result &= err == 0;
> 
> 
> why no checking of b value here?

right, ok

> 
> > +
> > +	/* not valid argument */
> > +	err = bpf_get_func_arg(ctx, 2, &z);
> > +	test3_result &= err == -EINVAL;
> > +
> > +	/* return value */
> > +	err = bpf_get_func_ret(ctx, &ret);
> > +	test3_result &= err == 0 && ret == 0;
> > +	return 1234;
> > +}
> > +
> > +__u64 test4_result = 0;
> > +SEC("fexit/bpf_modify_return_test")
> > +int BPF_PROG(fexit_test, int _a, __u64 _b, int _ret)
> > +{
> > +	__u64 cnt = bpf_get_func_arg_cnt(ctx);
> > +	__u64 a = 0, b = 0, z = 0, ret = 0;
> > +	__s64 err;
> > +
> > +	test4_result = cnt == 2;
> > +
> > +	/* valid arguments */
> > +	err = bpf_get_func_arg(ctx, 0, &a);
> > +	test4_result &= err == 0 && (int) a == 1;
> > +
> > +	err = bpf_get_func_arg(ctx, 1, &b);
> > +	test4_result &= err == 0;
> 
> 
> same, for consistency, b should have been checked, no?

ok

thanks,
jirka
Andrii Nakryiko Dec. 7, 2021, 10:54 p.m. UTC | #3 
On Tue, Dec 7, 2021 at 10:14 AM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Mon, Dec 06, 2021 at 02:03:54PM -0800, Andrii Nakryiko wrote:
> >
> > On 12/4/21 6:07 AM, Jiri Olsa wrote:
> > > Adding tests for get_func_[arg|ret|arg_cnt] helpers.
> > > Using these helpers in fentry/fexit/fmod_ret programs.
> > >
> > > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > > ---
> > >   .../bpf/prog_tests/get_func_args_test.c       |  38 ++++++
> > >   .../selftests/bpf/progs/get_func_args_test.c  | 112 ++++++++++++++++++
> > >   2 files changed, 150 insertions(+)
> > >   create mode 100644 tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> > >   create mode 100644 tools/testing/selftests/bpf/progs/get_func_args_test.c
> > >
> > > diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> > > new file mode 100644
> > > index 000000000000..c24807ae4361
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
> > > @@ -0,0 +1,38 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +#include <test_progs.h>
> > > +#include "get_func_args_test.skel.h"
> > > +
> > > +void test_get_func_args_test(void)
> > > +{
> > > +   struct get_func_args_test *skel = NULL;
> > > +   __u32 duration = 0, retval;
> > > +   int err, prog_fd;
> > > +
> > > +   skel = get_func_args_test__open_and_load();
> > > +   if (!ASSERT_OK_PTR(skel, "get_func_args_test__open_and_load"))
> > > +           return;
> > > +
> > > +   err = get_func_args_test__attach(skel);
> > > +   if (!ASSERT_OK(err, "get_func_args_test__attach"))
> > > +           goto cleanup;
> > > +
> > > +   prog_fd = bpf_program__fd(skel->progs.test1);
> > > +   err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> > > +                           NULL, NULL, &retval, &duration);
> > > +   ASSERT_OK(err, "test_run");
> > > +   ASSERT_EQ(retval, 0, "test_run");
> > > +
> > > +   prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
> > > +   err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
> > > +                           NULL, NULL, &retval, &duration);
> > > +   ASSERT_OK(err, "test_run");
> > > +   ASSERT_EQ(retval, 1234, "test_run");
> >
> >
> > are the other two programs executed implicitly during one of those test
> > runs? Can you please leave a small comment somewhere here if that's true?
>
> test1 triggers all the bpf_fentry_test* fentry/fexits
> fmod_ret_test triggers the rest, I'll put it in comment
>
> >
> >
> > > +
> > > +   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");
> > > +
> > > +cleanup:
> > > +   get_func_args_test__destroy(skel);
> > > +}
> > > diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> > > new file mode 100644
> > > index 000000000000..0d0a67c849ae
> > > --- /dev/null
> > > +++ b/tools/testing/selftests/bpf/progs/get_func_args_test.c
> > > @@ -0,0 +1,112 @@
> > > +// SPDX-License-Identifier: GPL-2.0
> > > +#include <linux/bpf.h>
> > > +#include <bpf/bpf_helpers.h>
> > > +#include <bpf/bpf_tracing.h>
> > > +#include <errno.h>
> > > +
> > > +char _license[] SEC("license") = "GPL";
> > > +
> > > +__u64 test1_result = 0;
> > > +SEC("fentry/bpf_fentry_test1")
> > > +int BPF_PROG(test1)
> > > +{
> > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > +   __u64 a = 0, z = 0, ret = 0;
> > > +   __s64 err;
> > > +
> > > +   test1_result = cnt == 1;
> > > +
> > > +   /* valid arguments */
> > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > +   test1_result &= err == 0 && (int) a == 1;
> >
> >
> > int cast unnecessary? but some ()'s wouldn't hurt...
>
> it is, 'a' is int and trampoline saves it with 32-bit register like:
>
>   mov    %edi,-0x8(%rbp)
>
> so the upper 4 bytes are not zeroed

oh, this is definitely worth a comment, it's quite a big gotcha we'll
need to remember


>
> >
> >
> > > +
> > > +   /* not valid argument */
> > > +   err = bpf_get_func_arg(ctx, 1, &z);
> > > +   test1_result &= err == -EINVAL;
> > > +
> > > +   /* return value fails in fentry */
> > > +   err = bpf_get_func_ret(ctx, &ret);
> > > +   test1_result &= err == -EINVAL;
> > > +   return 0;
> > > +}
> > > +
> > > +__u64 test2_result = 0;
> > > +SEC("fexit/bpf_fentry_test2")
> > > +int BPF_PROG(test2)
> > > +{
> > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > +   __s64 err;
> > > +
> > > +   test2_result = cnt == 2;
> > > +
> > > +   /* valid arguments */
> > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > +   test2_result &= err == 0 && (int) a == 2;
> > > +
> > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > +   test2_result &= err == 0 && b == 3;
> > > +
> > > +   /* not valid argument */
> > > +   err = bpf_get_func_arg(ctx, 2, &z);
> > > +   test2_result &= err == -EINVAL;
> > > +
> > > +   /* return value */
> > > +   err = bpf_get_func_ret(ctx, &ret);
> > > +   test2_result &= err == 0 && ret == 5;
> > > +   return 0;
> > > +}
> > > +
> > > +__u64 test3_result = 0;
> > > +SEC("fmod_ret/bpf_modify_return_test")
> > > +int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
> > > +{
> > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > +   __s64 err;
> > > +
> > > +   test3_result = cnt == 2;
> > > +
> > > +   /* valid arguments */
> > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > +   test3_result &= err == 0 && (int) a == 1;
> > > +
> > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > +   test3_result &= err == 0;
> >
> >
> > why no checking of b value here?
>
> right, ok
>
> >
> > > +
> > > +   /* not valid argument */
> > > +   err = bpf_get_func_arg(ctx, 2, &z);
> > > +   test3_result &= err == -EINVAL;
> > > +
> > > +   /* return value */
> > > +   err = bpf_get_func_ret(ctx, &ret);
> > > +   test3_result &= err == 0 && ret == 0;
> > > +   return 1234;
> > > +}
> > > +
> > > +__u64 test4_result = 0;
> > > +SEC("fexit/bpf_modify_return_test")
> > > +int BPF_PROG(fexit_test, int _a, __u64 _b, int _ret)
> > > +{
> > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > +   __s64 err;
> > > +
> > > +   test4_result = cnt == 2;
> > > +
> > > +   /* valid arguments */
> > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > +   test4_result &= err == 0 && (int) a == 1;
> > > +
> > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > +   test4_result &= err == 0;
> >
> >
> > same, for consistency, b should have been checked, no?
>
> ok
>
> thanks,
> jirka
>
Jiri Olsa Dec. 8, 2021, 4:38 p.m. UTC | #4 
On Tue, Dec 07, 2021 at 02:54:33PM -0800, Andrii Nakryiko wrote:

SNIP

> > > > +__u64 test1_result = 0;
> > > > +SEC("fentry/bpf_fentry_test1")
> > > > +int BPF_PROG(test1)
> > > > +{
> > > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > > +   __u64 a = 0, z = 0, ret = 0;
> > > > +   __s64 err;
> > > > +
> > > > +   test1_result = cnt == 1;
> > > > +
> > > > +   /* valid arguments */
> > > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > > +   test1_result &= err == 0 && (int) a == 1;
> > >
> > >
> > > int cast unnecessary? but some ()'s wouldn't hurt...
> >
> > it is, 'a' is int and trampoline saves it with 32-bit register like:
> >
> >   mov    %edi,-0x8(%rbp)
> >
> > so the upper 4 bytes are not zeroed
> 
> oh, this is definitely worth a comment, it's quite a big gotcha we'll
> need to remember


ok, will add comment for that

jirka

> 
> 
> >
> > >
> > >
> > > > +
> > > > +   /* not valid argument */
> > > > +   err = bpf_get_func_arg(ctx, 1, &z);
> > > > +   test1_result &= err == -EINVAL;
> > > > +
> > > > +   /* return value fails in fentry */
> > > > +   err = bpf_get_func_ret(ctx, &ret);
> > > > +   test1_result &= err == -EINVAL;
> > > > +   return 0;
> > > > +}
> > > > +
> > > > +__u64 test2_result = 0;
> > > > +SEC("fexit/bpf_fentry_test2")
> > > > +int BPF_PROG(test2)
> > > > +{
> > > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > > +   __s64 err;
> > > > +
> > > > +   test2_result = cnt == 2;
> > > > +
> > > > +   /* valid arguments */
> > > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > > +   test2_result &= err == 0 && (int) a == 2;
> > > > +
> > > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > > +   test2_result &= err == 0 && b == 3;
> > > > +
> > > > +   /* not valid argument */
> > > > +   err = bpf_get_func_arg(ctx, 2, &z);
> > > > +   test2_result &= err == -EINVAL;
> > > > +
> > > > +   /* return value */
> > > > +   err = bpf_get_func_ret(ctx, &ret);
> > > > +   test2_result &= err == 0 && ret == 5;
> > > > +   return 0;
> > > > +}
> > > > +
> > > > +__u64 test3_result = 0;
> > > > +SEC("fmod_ret/bpf_modify_return_test")
> > > > +int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
> > > > +{
> > > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > > +   __s64 err;
> > > > +
> > > > +   test3_result = cnt == 2;
> > > > +
> > > > +   /* valid arguments */
> > > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > > +   test3_result &= err == 0 && (int) a == 1;
> > > > +
> > > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > > +   test3_result &= err == 0;
> > >
> > >
> > > why no checking of b value here?
> >
> > right, ok
> >
> > >
> > > > +
> > > > +   /* not valid argument */
> > > > +   err = bpf_get_func_arg(ctx, 2, &z);
> > > > +   test3_result &= err == -EINVAL;
> > > > +
> > > > +   /* return value */
> > > > +   err = bpf_get_func_ret(ctx, &ret);
> > > > +   test3_result &= err == 0 && ret == 0;
> > > > +   return 1234;
> > > > +}
> > > > +
> > > > +__u64 test4_result = 0;
> > > > +SEC("fexit/bpf_modify_return_test")
> > > > +int BPF_PROG(fexit_test, int _a, __u64 _b, int _ret)
> > > > +{
> > > > +   __u64 cnt = bpf_get_func_arg_cnt(ctx);
> > > > +   __u64 a = 0, b = 0, z = 0, ret = 0;
> > > > +   __s64 err;
> > > > +
> > > > +   test4_result = cnt == 2;
> > > > +
> > > > +   /* valid arguments */
> > > > +   err = bpf_get_func_arg(ctx, 0, &a);
> > > > +   test4_result &= err == 0 && (int) a == 1;
> > > > +
> > > > +   err = bpf_get_func_arg(ctx, 1, &b);
> > > > +   test4_result &= err == 0;
> > >
> > >
> > > same, for consistency, b should have been checked, no?
> >
> > ok
> >
> > thanks,
> > jirka
> >
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
new file mode 100644
index 000000000000..c24807ae4361
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/get_func_args_test.c
@@ -0,0 +1,38 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <test_progs.h>
+#include "get_func_args_test.skel.h"
+
+void test_get_func_args_test(void)
+{
+	struct get_func_args_test *skel = NULL;
+	__u32 duration = 0, retval;
+	int err, prog_fd;
+
+	skel = get_func_args_test__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "get_func_args_test__open_and_load"))
+		return;
+
+	err = get_func_args_test__attach(skel);
+	if (!ASSERT_OK(err, "get_func_args_test__attach"))
+		goto cleanup;
+
+	prog_fd = bpf_program__fd(skel->progs.test1);
+	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
+				NULL, NULL, &retval, &duration);
+	ASSERT_OK(err, "test_run");
+	ASSERT_EQ(retval, 0, "test_run");
+
+	prog_fd = bpf_program__fd(skel->progs.fmod_ret_test);
+	err = bpf_prog_test_run(prog_fd, 1, NULL, 0,
+				NULL, NULL, &retval, &duration);
+	ASSERT_OK(err, "test_run");
+	ASSERT_EQ(retval, 1234, "test_run");
+
+	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");
+
+cleanup:
+	get_func_args_test__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/get_func_args_test.c b/tools/testing/selftests/bpf/progs/get_func_args_test.c
new file mode 100644
index 000000000000..0d0a67c849ae
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/get_func_args_test.c
@@ -0,0 +1,112 @@ 
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/bpf.h>
+#include <bpf/bpf_helpers.h>
+#include <bpf/bpf_tracing.h>
+#include <errno.h>
+
+char _license[] SEC("license") = "GPL";
+
+__u64 test1_result = 0;
+SEC("fentry/bpf_fentry_test1")
+int BPF_PROG(test1)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, z = 0, ret = 0;
+	__s64 err;
+
+	test1_result = cnt == 1;
+
+	/* valid arguments */
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test1_result &= err == 0 && (int) a == 1;
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 1, &z);
+	test1_result &= err == -EINVAL;
+
+	/* return value fails in fentry */
+	err = bpf_get_func_ret(ctx, &ret);
+	test1_result &= err == -EINVAL;
+	return 0;
+}
+
+__u64 test2_result = 0;
+SEC("fexit/bpf_fentry_test2")
+int BPF_PROG(test2)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, b = 0, z = 0, ret = 0;
+	__s64 err;
+
+	test2_result = cnt == 2;
+
+	/* valid arguments */
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test2_result &= err == 0 && (int) a == 2;
+
+	err = bpf_get_func_arg(ctx, 1, &b);
+	test2_result &= err == 0 && b == 3;
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 2, &z);
+	test2_result &= err == -EINVAL;
+
+	/* return value */
+	err = bpf_get_func_ret(ctx, &ret);
+	test2_result &= err == 0 && ret == 5;
+	return 0;
+}
+
+__u64 test3_result = 0;
+SEC("fmod_ret/bpf_modify_return_test")
+int BPF_PROG(fmod_ret_test, int _a, int *_b, int _ret)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, b = 0, z = 0, ret = 0;
+	__s64 err;
+
+	test3_result = cnt == 2;
+
+	/* valid arguments */
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test3_result &= err == 0 && (int) a == 1;
+
+	err = bpf_get_func_arg(ctx, 1, &b);
+	test3_result &= err == 0;
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 2, &z);
+	test3_result &= err == -EINVAL;
+
+	/* return value */
+	err = bpf_get_func_ret(ctx, &ret);
+	test3_result &= err == 0 && ret == 0;
+	return 1234;
+}
+
+__u64 test4_result = 0;
+SEC("fexit/bpf_modify_return_test")
+int BPF_PROG(fexit_test, int _a, __u64 _b, int _ret)
+{
+	__u64 cnt = bpf_get_func_arg_cnt(ctx);
+	__u64 a = 0, b = 0, z = 0, ret = 0;
+	__s64 err;
+
+	test4_result = cnt == 2;
+
+	/* valid arguments */
+	err = bpf_get_func_arg(ctx, 0, &a);
+	test4_result &= err == 0 && (int) a == 1;
+
+	err = bpf_get_func_arg(ctx, 1, &b);
+	test4_result &= err == 0;
+
+	/* not valid argument */
+	err = bpf_get_func_arg(ctx, 2, &z);
+	test4_result &= err == -EINVAL;
+
+	/* return value */
+	err = bpf_get_func_ret(ctx, &ret);
+	test4_result &= err == 0 && ret == 1234;
+	return 0;
+}