diff mbox series

[v3,bpf-next,2/2] selftests/bpf: Add selftest for fill_link_info

Message ID 20230731111313.3745-3-laoar.shao@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Fix fill_link_info and add selftest | expand

Checks

Context Check Description
bpf/vmtest-bpf-next-PR success PR summary
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next, async
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 9 this patch: 9
netdev/cc_maintainers warning 4 maintainers not CCed: yonghong.song@linux.dev mykolal@fb.com shuah@kernel.org linux-kselftest@vger.kernel.org
netdev/build_clang success Errors and warnings before: 9 this patch: 9
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/checkpatch warning CHECK: Alignment should match open parenthesis CHECK: No space is necessary after a cast WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 81 exceeds 80 columns WARNING: line length of 82 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns WARNING: line length of 85 exceeds 80 columns WARNING: line length of 86 exceeds 80 columns WARNING: line length of 87 exceeds 80 columns WARNING: line length of 88 exceeds 80 columns WARNING: line length of 89 exceeds 80 columns WARNING: line length of 90 exceeds 80 columns WARNING: line length of 91 exceeds 80 columns WARNING: line length of 93 exceeds 80 columns WARNING: line length of 94 exceeds 80 columns WARNING: line length of 96 exceeds 80 columns WARNING: line length of 97 exceeds 80 columns
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Commit Message

Yafang Shao July 31, 2023, 11:13 a.m. UTC 
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@gmail.com>
---
 tools/testing/selftests/bpf/DENYLIST.aarch64       |   3 +
 .../selftests/bpf/prog_tests/fill_link_info.c      | 369 +++++++++++++++++++++
 .../selftests/bpf/progs/test_fill_link_info.c      |  42 +++
 3 files changed, 414 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

Comments

Alexei Starovoitov Aug. 2, 2023, 8:57 p.m. UTC | #1 
On Mon, Jul 31, 2023 at 4:13 AM Yafang Shao <laoar.shao@gmail.com> 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@gmail.com>
> ---
>  tools/testing/selftests/bpf/DENYLIST.aarch64       |   3 +
>  .../selftests/bpf/prog_tests/fill_link_info.c      | 369 +++++++++++++++++++++
>  .../selftests/bpf/progs/test_fill_link_info.c      |  42 +++
>  3 files changed, 414 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


BPF CI isn't happy, because s390 also needs to be updated?
We'll just mark patches as 'changes requested' next time without
explicit emails.
Yonghong Song Aug. 2, 2023, 11 p.m. UTC | #2 
On 7/31/23 4:13 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@gmail.com>
> ---
>   tools/testing/selftests/bpf/DENYLIST.aarch64       |   3 +
>   .../selftests/bpf/prog_tests/fill_link_info.c      | 369 +++++++++++++++++++++
>   .../selftests/bpf/progs/test_fill_link_info.c      |  42 +++
>   3 files changed, 414 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..948ae60
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> @@ -0,0 +1,369 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
> +
> +#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;
> +
> +	switch (info.type) {
> +	case BPF_LINK_TYPE_PERF_EVENT:
> +		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 kptr setting is not permitted or MAX_SYMS is reached */

'kptr' has special meaning in bpf ecosystem (searching verifier.c).
Could you re-word the above comments? I am not sure what it means.

> +			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:
> +			break;
> +		}
> +		break;
> +	default:
> +		switch (type) {
> +		case BPF_PERF_EVENT_KPROBE:
> +		case BPF_PERF_EVENT_KRETPROBE:
> +		case BPF_PERF_EVENT_TRACEPOINT:
> +		case BPF_PERF_EVENT_UPROBE:
> +		case BPF_PERF_EVENT_URETPROBE:
> +			err = -1;
> +			break;
> +		default:
> +			break;
> +		}
> +		break;

Is this whole 'default' thing ever possible?
Maybe you should have ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT) 
first and then you won't need a top switch statement?


> +	}
> +	return err;
> +}
> +
> +static void kprobe_fill_invalid_user_buffer(int fd)
> +{
> +	struct bpf_link_info info;
> +	__u32 len = sizeof(info);
> +	int err;
> +
> +	memset(&info, 0, sizeof(info));
> +
> +	info.perf_event.kprobe.func_name = 0x1; /* invalid address */
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
> +
> +	info.perf_event.kprobe.name_len = 64;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EFAULT, "invalid_buff");
> +
> +	info.perf_event.kprobe.func_name = 0;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EINVAL, "invalid_len");
> +
> +	ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
> +	ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
> +	ASSERT_EQ(info.perf_event.type, 0, "type");
> +}
> +
> +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;
> +	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);
> +	if (!ASSERT_GE(link_fd, 0, "link_fd"))
> +		return;

There is no need to check validity of link_fd if skel->links.kprobe_run 
is valid.

> +
> +	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, offset ?: entry_offset);

offset is always 0 here.

> +		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_tp_fill_link_info(struct test_fill_link_info *skel)
> +{
> +	int link_fd, err;
> +
> +	skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
> +	if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
> +		return;
> +
> +	link_fd = bpf_link__fd(skel->links.tp_run);
> +	if (!ASSERT_GE(link_fd, 0, "link_fd"))
> +		return;

No need to check link_fd.

> +
> +	err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
> +	ASSERT_OK(err, "verify_perf_link_info");
> +	bpf_link__detach(skel->links.tp_run);
> +}
> +
> +static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
> +				       enum bpf_perf_event_type type, ssize_t offset,
> +				       bool retprobe)
> +{
> +	int link_fd, err;
> +
> +	skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run, retprobe,
> +							    0, /* self pid */
> +							    UPROBE_FILE, offset);
> +	if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
> +		return;
> +
> +	link_fd = bpf_link__fd(skel->links.uprobe_run);
> +	if (!ASSERT_GE(link_fd, 0, "link_fd"))
> +		return;

No need to check link_fd.

> +
> +	err = verify_perf_link_info(link_fd, type, 0, offset, 0);
> +	ASSERT_OK(err, "verify_perf_link_info");
> +	bpf_link__detach(skel->links.uprobe_run);
> +}
> +
> +static int verify_kmulti_link_info(int fd, const __u64 *addrs, bool retprobe)
> +{
> +	__u64 kmulti_addrs[KMULTI_CNT];
> +	struct bpf_link_info info;
> +	__u32 len = sizeof(info);
> +	int flags, i, err = 0;
> +
> +	memset(&info, 0, sizeof(info));
> +
> +again:
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	if (!ASSERT_OK(err, "get_link_info"))
> +		return -1;
> +
> +	ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type");

You can do
	if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type"))
		return -1;

and then there is no need for below switch statement.

> +	switch (info.type) {
> +	case BPF_LINK_TYPE_KPROBE_MULTI:
> +		ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
> +		flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
> +		if (!retprobe)
> +			ASSERT_EQ(flags, 0, "kmulti_flags");
> +		else
> +			ASSERT_NEQ(flags, 0, "kretmulti_flags");
> +
> +		if (!info.kprobe_multi.addrs) {
> +			info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
> +			goto again;
> +		}
> +		for (i = 0; i < KMULTI_CNT; i++)
> +			ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> +		break;
> +	default:
> +		err = -1;
> +		break;
> +	}
> +	return err;
> +}
> +
> +static void verify_kmulti_user_buffer(int fd, const __u64 *addrs)
> +{
> +	__u64 kmulti_addrs[KMULTI_CNT];
> +	struct bpf_link_info info;
> +	__u32 len = sizeof(info);
> +	int err, i;
> +
> +	memset(&info, 0, sizeof(info));
> +
> +	info.kprobe_multi.count = KMULTI_CNT;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EINVAL, "no_addr");
> +
> +	info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
> +	info.kprobe_multi.count = 0;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EINVAL, "no_cnt");
> +
> +	for (i = 0; i < KMULTI_CNT; i++)
> +		kmulti_addrs[i] = 0;
> +	info.kprobe_multi.count = KMULTI_CNT - 1;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
> +	for (i = 0; i < KMULTI_CNT - 1; i++)
> +		ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> +	ASSERT_EQ(kmulti_addrs[i], 0, "kmulti_addrs");
> +
> +	for (i = 0; i < KMULTI_CNT; i++)
> +		kmulti_addrs[i] = 0;
> +	info.kprobe_multi.count = KMULTI_CNT + 1;
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, 0, "bigger_cnt");
> +	for (i = 0; i < KMULTI_CNT; i++)
> +		ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> +
> +	info.kprobe_multi.count = KMULTI_CNT;
> +	info.kprobe_multi.addrs = 0x1; /* invalid addr */
> +	err = bpf_link_get_info_by_fd(fd, &info, &len);
> +	ASSERT_EQ(err, -EFAULT, "invalid_buff");
> +}
> +
> +static int symbols_cmp_r(const void *a, const void *b)
> +{
> +	const char **str_a = (const char **) a;
> +	const char **str_b = (const char **) b;
> +
> +	return strcmp(*str_a, *str_b);
> +}
> +
> +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;
> +
> +	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);
> +	if (!ASSERT_GE(link_fd, 0, "link_fd"))
> +		return;

No need to check link_fd.

> +
> +	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");
> +	bpf_link__detach(skel->links.kmulti_run);
> +}
> +
> +void test_fill_link_info(void)
> +{
> +	struct test_fill_link_info *skel;
> +	ssize_t offset;
> +
> +	skel = test_fill_link_info__open_and_load();
> +	if (!ASSERT_OK_PTR(skel, "skel_open"))
> +		goto cleanup;

Just return here if skel is invalid.

> +
> +	/* load kallsyms to compare the addr */
> +	if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
> +		return;

You actually need to go to 'cleanup' here.

> +	if (test__start_subtest("kprobe_link_info"))
> +		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, false);
> +	if (test__start_subtest("kretprobe_link_info"))
> +		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, true, false);
> +	if (test__start_subtest("kprobe_fill_invalid_user_buff"))
> +		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, true);
> +	if (test__start_subtest("tracepoint_link_info"))
> +		test_tp_fill_link_info(skel);
> +
> +	offset = get_uprobe_offset(&uprobe_func);
> +	if (test__start_subtest("uprobe_link_info"))
> +		test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE, offset, false);
> +	if (test__start_subtest("uretprobe_link_info"))
> +		test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE, offset, true);
> +	if (test__start_subtest("kprobe_multi_link_info"))
> +		test_kprobe_multi_fill_link_info(skel, false, false);
> +	if (test__start_subtest("kretprobe_multi_link_info"))
> +		test_kprobe_multi_fill_link_info(skel, true, false);
> +	if (test__start_subtest("kprobe_multi_ubuff"))
> +		test_kprobe_multi_fill_link_info(skel, true, true);
> +
> +cleanup:
> +	test_fill_link_info__destroy(skel);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
> new file mode 100644
> index 0000000..564f402
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
> @@ -0,0 +1,42 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
> +
> +#include "vmlinux.h"
> +#include <bpf/bpf_tracing.h>
> +#include <stdbool.h>
> +
> +extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak;
> +
> +/* This function is here to have CONFIG_X86_KERNEL_IBT
> + * used and added to object BTF.
> + */
> +int unused(void)
> +{
> +	return CONFIG_X86_KERNEL_IBT ? 0 : 1;
> +}
> +
> +SEC("kprobe")
> +int BPF_PROG(kprobe_run)
> +{
> +	return 0;
> +}
> +
> +SEC("uprobe")
> +int BPF_PROG(uprobe_run)
> +{
> +	return 0;
> +}
> +
> +SEC("tracepoint")
> +int BPF_PROG(tp_run)
> +{
> +	return 0;
> +}
> +
> +SEC("kprobe.multi")
> +int BPF_PROG(kmulti_run)
> +{
> +	return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
Yafang Shao Aug. 3, 2023, 2:28 p.m. UTC | #3 
On Thu, Aug 3, 2023 at 4:57 AM Alexei Starovoitov
<alexei.starovoitov@gmail.com> wrote:
>
> On Mon, Jul 31, 2023 at 4:13 AM Yafang Shao <laoar.shao@gmail.com> 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@gmail.com>
> > ---
> >  tools/testing/selftests/bpf/DENYLIST.aarch64       |   3 +
> >  .../selftests/bpf/prog_tests/fill_link_info.c      | 369 +++++++++++++++++++++
> >  .../selftests/bpf/progs/test_fill_link_info.c      |  42 +++
> >  3 files changed, 414 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
>
>
> BPF CI isn't happy, because s390 also needs to be updated?

I thought it was caused by other issues. The s390 server may not be so stable.
kprobe_multi is supported by s390. Before sending this series, I have
verified the BPF CI on github, and it can run successfully on s390 :
https://github.com/kernel-patches/bpf/actions/runs/5711429876/job/15473251677#step:6:4972

> We'll just mark patches as 'changes requested' next time without
> explicit emails.
Yafang Shao Aug. 3, 2023, 2:32 p.m. UTC | #4 
On Thu, Aug 3, 2023 at 7:00 AM Yonghong Song <yonghong.song@linux.dev> wrote:
>
>
>
> On 7/31/23 4:13 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@gmail.com>
> > ---
> >   tools/testing/selftests/bpf/DENYLIST.aarch64       |   3 +
> >   .../selftests/bpf/prog_tests/fill_link_info.c      | 369 +++++++++++++++++++++
> >   .../selftests/bpf/progs/test_fill_link_info.c      |  42 +++
> >   3 files changed, 414 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..948ae60
> > --- /dev/null
> > +++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
> > @@ -0,0 +1,369 @@
> > +// SPDX-License-Identifier: GPL-2.0
> > +/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
> > +
> > +#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;
> > +
> > +     switch (info.type) {
> > +     case BPF_LINK_TYPE_PERF_EVENT:
> > +             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 kptr setting is not permitted or MAX_SYMS is reached */
>
> 'kptr' has special meaning in bpf ecosystem (searching verifier.c).
> Could you re-word the above comments? I am not sure what it means.

It is the kernel.kptr_restrict sysctl knob.
Will re-word it.

>
> > +                     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:
> > +                     break;
> > +             }
> > +             break;
> > +     default:
> > +             switch (type) {
> > +             case BPF_PERF_EVENT_KPROBE:
> > +             case BPF_PERF_EVENT_KRETPROBE:
> > +             case BPF_PERF_EVENT_TRACEPOINT:
> > +             case BPF_PERF_EVENT_UPROBE:
> > +             case BPF_PERF_EVENT_URETPROBE:
> > +                     err = -1;
> > +                     break;
> > +             default:
> > +                     break;
> > +             }
> > +             break;
>
> Is this whole 'default' thing ever possible?
> Maybe you should have ASSERT_EQ(info.type, BPF_LINK_TYPE_PERF_EVENT)
> first and then you won't need a top switch statement?

Will change it.

>
>
> > +     }
> > +     return err;
> > +}
> > +
> > +static void kprobe_fill_invalid_user_buffer(int fd)
> > +{
> > +     struct bpf_link_info info;
> > +     __u32 len = sizeof(info);
> > +     int err;
> > +
> > +     memset(&info, 0, sizeof(info));
> > +
> > +     info.perf_event.kprobe.func_name = 0x1; /* invalid address */
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
> > +
> > +     info.perf_event.kprobe.name_len = 64;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EFAULT, "invalid_buff");
> > +
> > +     info.perf_event.kprobe.func_name = 0;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EINVAL, "invalid_len");
> > +
> > +     ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
> > +     ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
> > +     ASSERT_EQ(info.perf_event.type, 0, "type");
> > +}
> > +
> > +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;
> > +     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);
> > +     if (!ASSERT_GE(link_fd, 0, "link_fd"))
> > +             return;
>
> There is no need to check validity of link_fd if skel->links.kprobe_run
> is valid.

Will change it and the others.

>
> > +
> > +     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, offset ?: entry_offset);
>
> offset is always 0 here.

Will simplify 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_tp_fill_link_info(struct test_fill_link_info *skel)
> > +{
> > +     int link_fd, err;
> > +
> > +     skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
> > +     if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
> > +             return;
> > +
> > +     link_fd = bpf_link__fd(skel->links.tp_run);
> > +     if (!ASSERT_GE(link_fd, 0, "link_fd"))
> > +             return;
>
> No need to check link_fd.
>
> > +
> > +     err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
> > +     ASSERT_OK(err, "verify_perf_link_info");
> > +     bpf_link__detach(skel->links.tp_run);
> > +}
> > +
> > +static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
> > +                                    enum bpf_perf_event_type type, ssize_t offset,
> > +                                    bool retprobe)
> > +{
> > +     int link_fd, err;
> > +
> > +     skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run, retprobe,
> > +                                                         0, /* self pid */
> > +                                                         UPROBE_FILE, offset);
> > +     if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
> > +             return;
> > +
> > +     link_fd = bpf_link__fd(skel->links.uprobe_run);
> > +     if (!ASSERT_GE(link_fd, 0, "link_fd"))
> > +             return;
>
> No need to check link_fd.
>
> > +
> > +     err = verify_perf_link_info(link_fd, type, 0, offset, 0);
> > +     ASSERT_OK(err, "verify_perf_link_info");
> > +     bpf_link__detach(skel->links.uprobe_run);
> > +}
> > +
> > +static int verify_kmulti_link_info(int fd, const __u64 *addrs, bool retprobe)
> > +{
> > +     __u64 kmulti_addrs[KMULTI_CNT];
> > +     struct bpf_link_info info;
> > +     __u32 len = sizeof(info);
> > +     int flags, i, err = 0;
> > +
> > +     memset(&info, 0, sizeof(info));
> > +
> > +again:
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     if (!ASSERT_OK(err, "get_link_info"))
> > +             return -1;
> > +
> > +     ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type");
>
> You can do
>         if (!ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type"))
>                 return -1;
>
> and then there is no need for below switch statement.

Will change it.

>
> > +     switch (info.type) {
> > +     case BPF_LINK_TYPE_KPROBE_MULTI:
> > +             ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
> > +             flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
> > +             if (!retprobe)
> > +                     ASSERT_EQ(flags, 0, "kmulti_flags");
> > +             else
> > +                     ASSERT_NEQ(flags, 0, "kretmulti_flags");
> > +
> > +             if (!info.kprobe_multi.addrs) {
> > +                     info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
> > +                     goto again;
> > +             }
> > +             for (i = 0; i < KMULTI_CNT; i++)
> > +                     ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> > +             break;
> > +     default:
> > +             err = -1;
> > +             break;
> > +     }
> > +     return err;
> > +}
> > +
> > +static void verify_kmulti_user_buffer(int fd, const __u64 *addrs)
> > +{
> > +     __u64 kmulti_addrs[KMULTI_CNT];
> > +     struct bpf_link_info info;
> > +     __u32 len = sizeof(info);
> > +     int err, i;
> > +
> > +     memset(&info, 0, sizeof(info));
> > +
> > +     info.kprobe_multi.count = KMULTI_CNT;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EINVAL, "no_addr");
> > +
> > +     info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
> > +     info.kprobe_multi.count = 0;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EINVAL, "no_cnt");
> > +
> > +     for (i = 0; i < KMULTI_CNT; i++)
> > +             kmulti_addrs[i] = 0;
> > +     info.kprobe_multi.count = KMULTI_CNT - 1;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
> > +     for (i = 0; i < KMULTI_CNT - 1; i++)
> > +             ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> > +     ASSERT_EQ(kmulti_addrs[i], 0, "kmulti_addrs");
> > +
> > +     for (i = 0; i < KMULTI_CNT; i++)
> > +             kmulti_addrs[i] = 0;
> > +     info.kprobe_multi.count = KMULTI_CNT + 1;
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, 0, "bigger_cnt");
> > +     for (i = 0; i < KMULTI_CNT; i++)
> > +             ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
> > +
> > +     info.kprobe_multi.count = KMULTI_CNT;
> > +     info.kprobe_multi.addrs = 0x1; /* invalid addr */
> > +     err = bpf_link_get_info_by_fd(fd, &info, &len);
> > +     ASSERT_EQ(err, -EFAULT, "invalid_buff");
> > +}
> > +
> > +static int symbols_cmp_r(const void *a, const void *b)
> > +{
> > +     const char **str_a = (const char **) a;
> > +     const char **str_b = (const char **) b;
> > +
> > +     return strcmp(*str_a, *str_b);
> > +}
> > +
> > +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;
> > +
> > +     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);
> > +     if (!ASSERT_GE(link_fd, 0, "link_fd"))
> > +             return;
>
> No need to check link_fd.
>
> > +
> > +     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");
> > +     bpf_link__detach(skel->links.kmulti_run);
> > +}
> > +
> > +void test_fill_link_info(void)
> > +{
> > +     struct test_fill_link_info *skel;
> > +     ssize_t offset;
> > +
> > +     skel = test_fill_link_info__open_and_load();
> > +     if (!ASSERT_OK_PTR(skel, "skel_open"))
> > +             goto cleanup;
>
> Just return here if skel is invalid.

Will change it.

>
> > +
> > +     /* load kallsyms to compare the addr */
> > +     if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
> > +             return;
>
> You actually need to go to 'cleanup' here.

will change it.
diff mbox series

Patch

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..948ae60
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/fill_link_info.c
@@ -0,0 +1,369 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
+
+#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;
+
+	switch (info.type) {
+	case BPF_LINK_TYPE_PERF_EVENT:
+		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 kptr setting 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:
+			break;
+		}
+		break;
+	default:
+		switch (type) {
+		case BPF_PERF_EVENT_KPROBE:
+		case BPF_PERF_EVENT_KRETPROBE:
+		case BPF_PERF_EVENT_TRACEPOINT:
+		case BPF_PERF_EVENT_UPROBE:
+		case BPF_PERF_EVENT_URETPROBE:
+			err = -1;
+			break;
+		default:
+			break;
+		}
+		break;
+	}
+	return err;
+}
+
+static void kprobe_fill_invalid_user_buffer(int fd)
+{
+	struct bpf_link_info info;
+	__u32 len = sizeof(info);
+	int err;
+
+	memset(&info, 0, sizeof(info));
+
+	info.perf_event.kprobe.func_name = 0x1; /* invalid address */
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EINVAL, "invalid_buff_and_len");
+
+	info.perf_event.kprobe.name_len = 64;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EFAULT, "invalid_buff");
+
+	info.perf_event.kprobe.func_name = 0;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EINVAL, "invalid_len");
+
+	ASSERT_EQ(info.perf_event.kprobe.addr, 0, "func_addr");
+	ASSERT_EQ(info.perf_event.kprobe.offset, 0, "func_offset");
+	ASSERT_EQ(info.perf_event.type, 0, "type");
+}
+
+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;
+	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);
+	if (!ASSERT_GE(link_fd, 0, "link_fd"))
+		return;
+
+	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, offset ?: entry_offset);
+		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_tp_fill_link_info(struct test_fill_link_info *skel)
+{
+	int link_fd, err;
+
+	skel->links.tp_run = bpf_program__attach_tracepoint(skel->progs.tp_run, TP_CAT, TP_NAME);
+	if (!ASSERT_OK_PTR(skel->links.tp_run, "attach_tp"))
+		return;
+
+	link_fd = bpf_link__fd(skel->links.tp_run);
+	if (!ASSERT_GE(link_fd, 0, "link_fd"))
+		return;
+
+	err = verify_perf_link_info(link_fd, BPF_PERF_EVENT_TRACEPOINT, 0, 0, 0);
+	ASSERT_OK(err, "verify_perf_link_info");
+	bpf_link__detach(skel->links.tp_run);
+}
+
+static void test_uprobe_fill_link_info(struct test_fill_link_info *skel,
+				       enum bpf_perf_event_type type, ssize_t offset,
+				       bool retprobe)
+{
+	int link_fd, err;
+
+	skel->links.uprobe_run = bpf_program__attach_uprobe(skel->progs.uprobe_run, retprobe,
+							    0, /* self pid */
+							    UPROBE_FILE, offset);
+	if (!ASSERT_OK_PTR(skel->links.uprobe_run, "attach_uprobe"))
+		return;
+
+	link_fd = bpf_link__fd(skel->links.uprobe_run);
+	if (!ASSERT_GE(link_fd, 0, "link_fd"))
+		return;
+
+	err = verify_perf_link_info(link_fd, type, 0, offset, 0);
+	ASSERT_OK(err, "verify_perf_link_info");
+	bpf_link__detach(skel->links.uprobe_run);
+}
+
+static int verify_kmulti_link_info(int fd, const __u64 *addrs, bool retprobe)
+{
+	__u64 kmulti_addrs[KMULTI_CNT];
+	struct bpf_link_info info;
+	__u32 len = sizeof(info);
+	int flags, i, err = 0;
+
+	memset(&info, 0, sizeof(info));
+
+again:
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	if (!ASSERT_OK(err, "get_link_info"))
+		return -1;
+
+	ASSERT_EQ(info.type, BPF_LINK_TYPE_KPROBE_MULTI, "kmulti_type");
+	switch (info.type) {
+	case BPF_LINK_TYPE_KPROBE_MULTI:
+		ASSERT_EQ(info.kprobe_multi.count, KMULTI_CNT, "func_cnt");
+		flags = info.kprobe_multi.flags & BPF_F_KPROBE_MULTI_RETURN;
+		if (!retprobe)
+			ASSERT_EQ(flags, 0, "kmulti_flags");
+		else
+			ASSERT_NEQ(flags, 0, "kretmulti_flags");
+
+		if (!info.kprobe_multi.addrs) {
+			info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
+			goto again;
+		}
+		for (i = 0; i < KMULTI_CNT; i++)
+			ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+		break;
+	default:
+		err = -1;
+		break;
+	}
+	return err;
+}
+
+static void verify_kmulti_user_buffer(int fd, const __u64 *addrs)
+{
+	__u64 kmulti_addrs[KMULTI_CNT];
+	struct bpf_link_info info;
+	__u32 len = sizeof(info);
+	int err, i;
+
+	memset(&info, 0, sizeof(info));
+
+	info.kprobe_multi.count = KMULTI_CNT;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EINVAL, "no_addr");
+
+	info.kprobe_multi.addrs = ptr_to_u64(kmulti_addrs);
+	info.kprobe_multi.count = 0;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EINVAL, "no_cnt");
+
+	for (i = 0; i < KMULTI_CNT; i++)
+		kmulti_addrs[i] = 0;
+	info.kprobe_multi.count = KMULTI_CNT - 1;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -ENOSPC, "smaller_cnt");
+	for (i = 0; i < KMULTI_CNT - 1; i++)
+		ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+	ASSERT_EQ(kmulti_addrs[i], 0, "kmulti_addrs");
+
+	for (i = 0; i < KMULTI_CNT; i++)
+		kmulti_addrs[i] = 0;
+	info.kprobe_multi.count = KMULTI_CNT + 1;
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, 0, "bigger_cnt");
+	for (i = 0; i < KMULTI_CNT; i++)
+		ASSERT_EQ(kmulti_addrs[i], addrs[i], "kmulti_addrs");
+
+	info.kprobe_multi.count = KMULTI_CNT;
+	info.kprobe_multi.addrs = 0x1; /* invalid addr */
+	err = bpf_link_get_info_by_fd(fd, &info, &len);
+	ASSERT_EQ(err, -EFAULT, "invalid_buff");
+}
+
+static int symbols_cmp_r(const void *a, const void *b)
+{
+	const char **str_a = (const char **) a;
+	const char **str_b = (const char **) b;
+
+	return strcmp(*str_a, *str_b);
+}
+
+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;
+
+	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);
+	if (!ASSERT_GE(link_fd, 0, "link_fd"))
+		return;
+
+	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");
+	bpf_link__detach(skel->links.kmulti_run);
+}
+
+void test_fill_link_info(void)
+{
+	struct test_fill_link_info *skel;
+	ssize_t offset;
+
+	skel = test_fill_link_info__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "skel_open"))
+		goto cleanup;
+
+	/* load kallsyms to compare the addr */
+	if (!ASSERT_OK(load_kallsyms_refresh(), "load_kallsyms_refresh"))
+		return;
+	if (test__start_subtest("kprobe_link_info"))
+		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, false);
+	if (test__start_subtest("kretprobe_link_info"))
+		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KRETPROBE, true, false);
+	if (test__start_subtest("kprobe_fill_invalid_user_buff"))
+		test_kprobe_fill_link_info(skel, BPF_PERF_EVENT_KPROBE, false, true);
+	if (test__start_subtest("tracepoint_link_info"))
+		test_tp_fill_link_info(skel);
+
+	offset = get_uprobe_offset(&uprobe_func);
+	if (test__start_subtest("uprobe_link_info"))
+		test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_UPROBE, offset, false);
+	if (test__start_subtest("uretprobe_link_info"))
+		test_uprobe_fill_link_info(skel, BPF_PERF_EVENT_URETPROBE, offset, true);
+	if (test__start_subtest("kprobe_multi_link_info"))
+		test_kprobe_multi_fill_link_info(skel, false, false);
+	if (test__start_subtest("kretprobe_multi_link_info"))
+		test_kprobe_multi_fill_link_info(skel, true, false);
+	if (test__start_subtest("kprobe_multi_ubuff"))
+		test_kprobe_multi_fill_link_info(skel, true, true);
+
+cleanup:
+	test_fill_link_info__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_fill_link_info.c b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
new file mode 100644
index 0000000..564f402
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_fill_link_info.c
@@ -0,0 +1,42 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (C) 2023 Yafang Shao <laoar.shao@gmail.com> */
+
+#include "vmlinux.h"
+#include <bpf/bpf_tracing.h>
+#include <stdbool.h>
+
+extern bool CONFIG_X86_KERNEL_IBT __kconfig __weak;
+
+/* This function is here to have CONFIG_X86_KERNEL_IBT
+ * used and added to object BTF.
+ */
+int unused(void)
+{
+	return CONFIG_X86_KERNEL_IBT ? 0 : 1;
+}
+
+SEC("kprobe")
+int BPF_PROG(kprobe_run)
+{
+	return 0;
+}
+
+SEC("uprobe")
+int BPF_PROG(uprobe_run)
+{
+	return 0;
+}
+
+SEC("tracepoint")
+int BPF_PROG(tp_run)
+{
+	return 0;
+}
+
+SEC("kprobe.multi")
+int BPF_PROG(kmulti_run)
+{
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";