diff mbox series

[bpf-next,v4,2/2] selftests/bpf: Add testcase for bpf_task_under_cgroup

Message ID 20230428071737.43849-3-zhoufeng.zf@bytedance.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Introduce a new kfunc of bpf_task_under_cgroup | expand

Checks

Context Check Description
netdev/series_format success Posting correctly formatted
netdev/tree_selection success Clearly marked for bpf-next
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: 8 this patch: 8
netdev/cc_maintainers success CCed 16 of 16 maintainers
netdev/build_clang success Errors and warnings before: 8 this patch: 8
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: 8 this patch: 8
netdev/checkpatch warning WARNING: Use of volatile is usually wrong: see Documentation/process/volatile-considered-harmful.rst WARNING: added, moved or deleted file(s), does MAINTAINERS need updating? WARNING: line length of 85 exceeds 80 columns
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0
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Commit Message

Feng Zhou April 28, 2023, 7:17 a.m. UTC 
From: Feng Zhou <zhoufeng.zf@bytedance.com>

test_progs:
Tests new kfunc bpf_task_under_cgroup().

The bpf program saves the new task's pid within a given cgroup to
the remote_pid, which is convenient for the user-mode program to
verify the test correctness.

The user-mode program creates its own mount namespace, and mounts the
cgroupsv2 hierarchy in there, call the fork syscall, then check if
remote_pid and local_pid are unequal.

Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
---
 tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
 .../bpf/prog_tests/task_under_cgroup.c        | 55 +++++++++++++++++++
 .../bpf/progs/test_task_under_cgroup.c        | 51 +++++++++++++++++
 3 files changed, 107 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
 create mode 100644 tools/testing/selftests/bpf/progs/test_task_under_cgroup.c

Comments

Yonghong Song April 28, 2023, 4:32 p.m. UTC | #1 
On 4/28/23 12:17 AM, Feng zhou wrote:
> From: Feng Zhou <zhoufeng.zf@bytedance.com>
> 
> test_progs:
> Tests new kfunc bpf_task_under_cgroup().
> 
> The bpf program saves the new task's pid within a given cgroup to
> the remote_pid, which is convenient for the user-mode program to
> verify the test correctness.
> 
> The user-mode program creates its own mount namespace, and mounts the
> cgroupsv2 hierarchy in there, call the fork syscall, then check if
> remote_pid and local_pid are unequal.
> 
> Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>

Ack with a few nits below.

Acked-by: Yonghong Song <yhs@fb.com>

> ---
>   tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
>   .../bpf/prog_tests/task_under_cgroup.c        | 55 +++++++++++++++++++
>   .../bpf/progs/test_task_under_cgroup.c        | 51 +++++++++++++++++
>   3 files changed, 107 insertions(+)
>   create mode 100644 tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
>   create mode 100644 tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
> 
> diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
> index c7463f3ec3c0..5061d9e24c16 100644
> --- a/tools/testing/selftests/bpf/DENYLIST.s390x
> +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
> @@ -26,3 +26,4 @@ user_ringbuf                             # failed to find kernel BTF type ID of
>   verif_stats                              # trace_vprintk__open_and_load unexpected error: -9                           (?)
>   xdp_bonding                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
>   xdp_metadata                             # JIT does not support calling kernel function                                (kfunc)
> +test_task_under_cgroup                   # JIT does not support calling kernel function                                (kfunc)
> diff --git a/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
> new file mode 100644
> index 000000000000..5e79dff86dec
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
> @@ -0,0 +1,55 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2023 Bytedance */
> +
> +#include <sys/syscall.h>
> +#include <test_progs.h>
> +#include <cgroup_helpers.h>
> +#include "test_task_under_cgroup.skel.h"
> +
> +#define FOO	"/foo"
> +
> +void test_task_under_cgroup(void)
> +{
> +	struct test_task_under_cgroup *skel;
> +	int ret, foo = -1;
> +	pid_t pid;
> +
> +	foo = test__join_cgroup(FOO);
> +	if (!ASSERT_OK(foo < 0, "cgroup_join_foo"))
> +		return;
> +
> +	skel = test_task_under_cgroup__open();
> +	if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open"))
> +		goto cleanup;
> +
> +	skel->rodata->local_pid = getpid();
> +	skel->bss->remote_pid = getpid();
> +	skel->rodata->cgid = get_cgroup_id(FOO);
> +
> +	ret = test_task_under_cgroup__load(skel);
> +	if (!ASSERT_OK(ret, "test_task_under_cgroup__load"))
> +		goto cleanup;
> +
> +	ret = test_task_under_cgroup__attach(skel);
> +	if (!ASSERT_OK(ret, "test_task_under_cgroup__attach"))
> +		goto cleanup;
> +
> +	pid = fork();
> +	if (pid == 0)
> +		exit(0);
> +	else if (pid == -1)
> +		printf("Couldn't fork process!\n");

ASSERT_* is preferred compared to 'printf'. Maybe ASSERT_TRUE(0, 
"Couldn't fork process")?

> +
> +	wait(NULL);
> +
> +	test_task_under_cgroup__detach(skel);
> +
> +	ASSERT_NEQ(skel->bss->remote_pid, skel->rodata->local_pid,
> +		   "test task_under_cgroup");
> +
> +cleanup:
> +	if (foo >= 0)

"if (foo >= 0)" is not needed. 'foo' is guaranteed ">= 0" as this point.

> +		close(foo);
> +
> +	test_task_under_cgroup__destroy(skel);
> +}
> diff --git a/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
> new file mode 100644
> index 000000000000..5bcb726d6d0a
> --- /dev/null
> +++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
> @@ -0,0 +1,51 @@
> +// SPDX-License-Identifier: GPL-2.0
> +/* Copyright (c) 2023 Bytedance */
> +
> +#include <vmlinux.h>
> +#include <bpf/bpf_tracing.h>
> +#include <bpf/bpf_helpers.h>
> +
> +#include "bpf_misc.h"
> +
> +struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
> +long bpf_task_under_cgroup(struct task_struct *task, struct cgroup *ancestor) __ksym;
> +void bpf_cgroup_release(struct cgroup *p) __ksym;
> +struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;
> +void bpf_task_release(struct task_struct *p) __ksym;
> +
> +const volatile int local_pid;
> +const volatile long cgid;

cgid cannot be a negative number. So let us do
const volatile __u64 cgid;

> +int remote_pid;
> +
> +SEC("tp_btf/task_newtask")
> +int BPF_PROG(handle__task_newtask, struct task_struct *task, u64 clone_flags)
> +{
> +	struct cgroup *cgrp = NULL;
> +	struct task_struct *acquired = NULL;

"acquired = NULL" is not needed. Just do "struct task_struct *acquired;".

> +
> +	if (local_pid != (bpf_get_current_pid_tgid() >> 32))
> +		return 0;
> +
> +	acquired = bpf_task_acquire(task);
> +	if (!acquired)
> +		return 0;
> +
> +	if (local_pid == acquired->tgid)
> +		goto out;
> +
> +	cgrp = bpf_cgroup_from_id(cgid);
> +	if (!cgrp)
> +		goto out;
> +
> +	if (bpf_task_under_cgroup(acquired, cgrp))
> +		remote_pid = acquired->tgid;
> +
> +out:
> +	if (acquired)
> +		bpf_task_release(acquired);
> +	if (cgrp)
> +		bpf_cgroup_release(cgrp);
> +	return 0;
> +}
> +
> +char _license[] SEC("license") = "GPL";
Feng Zhou May 4, 2023, 3:23 a.m. UTC | #2 
在 2023/4/29 00:32, Yonghong Song 写道:
> 
> 
> On 4/28/23 12:17 AM, Feng zhou wrote:
>> From: Feng Zhou <zhoufeng.zf@bytedance.com>
>>
>> test_progs:
>> Tests new kfunc bpf_task_under_cgroup().
>>
>> The bpf program saves the new task's pid within a given cgroup to
>> the remote_pid, which is convenient for the user-mode program to
>> verify the test correctness.
>>
>> The user-mode program creates its own mount namespace, and mounts the
>> cgroupsv2 hierarchy in there, call the fork syscall, then check if
>> remote_pid and local_pid are unequal.
>>
>> Signed-off-by: Feng Zhou <zhoufeng.zf@bytedance.com>
> 
> Ack with a few nits below.
> 
> Acked-by: Yonghong Song <yhs@fb.com>
> 
>> ---
>>   tools/testing/selftests/bpf/DENYLIST.s390x    |  1 +
>>   .../bpf/prog_tests/task_under_cgroup.c        | 55 +++++++++++++++++++
>>   .../bpf/progs/test_task_under_cgroup.c        | 51 +++++++++++++++++
>>   3 files changed, 107 insertions(+)
>>   create mode 100644 
>> tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
>>   create mode 100644 
>> tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
>>
>> diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x 
>> b/tools/testing/selftests/bpf/DENYLIST.s390x
>> index c7463f3ec3c0..5061d9e24c16 100644
>> --- a/tools/testing/selftests/bpf/DENYLIST.s390x
>> +++ b/tools/testing/selftests/bpf/DENYLIST.s390x
>> @@ -26,3 +26,4 @@ user_ringbuf                             # failed to 
>> find kernel BTF type ID of
>>   verif_stats                              # 
>> trace_vprintk__open_and_load unexpected error: 
>> -9                           (?)
>>   xdp_bonding                              # failed to auto-attach 
>> program 'trace_on_entry': -524                        (trampoline)
>>   xdp_metadata                             # JIT does not support 
>> calling kernel function                                (kfunc)
>> +test_task_under_cgroup                   # JIT does not support 
>> calling kernel function                                (kfunc)
>> diff --git 
>> a/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c 
>> b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
>> new file mode 100644
>> index 000000000000..5e79dff86dec
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
>> @@ -0,0 +1,55 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2023 Bytedance */
>> +
>> +#include <sys/syscall.h>
>> +#include <test_progs.h>
>> +#include <cgroup_helpers.h>
>> +#include "test_task_under_cgroup.skel.h"
>> +
>> +#define FOO    "/foo"
>> +
>> +void test_task_under_cgroup(void)
>> +{
>> +    struct test_task_under_cgroup *skel;
>> +    int ret, foo = -1;
>> +    pid_t pid;
>> +
>> +    foo = test__join_cgroup(FOO);
>> +    if (!ASSERT_OK(foo < 0, "cgroup_join_foo"))
>> +        return;
>> +
>> +    skel = test_task_under_cgroup__open();
>> +    if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open"))
>> +        goto cleanup;
>> +
>> +    skel->rodata->local_pid = getpid();
>> +    skel->bss->remote_pid = getpid();
>> +    skel->rodata->cgid = get_cgroup_id(FOO);
>> +
>> +    ret = test_task_under_cgroup__load(skel);
>> +    if (!ASSERT_OK(ret, "test_task_under_cgroup__load"))
>> +        goto cleanup;
>> +
>> +    ret = test_task_under_cgroup__attach(skel);
>> +    if (!ASSERT_OK(ret, "test_task_under_cgroup__attach"))
>> +        goto cleanup;
>> +
>> +    pid = fork();
>> +    if (pid == 0)
>> +        exit(0);
>> +    else if (pid == -1)
>> +        printf("Couldn't fork process!\n");
> 
> ASSERT_* is preferred compared to 'printf'. Maybe ASSERT_TRUE(0, 
> "Couldn't fork process")?
> 

Will do.

>> +
>> +    wait(NULL);
>> +
>> +    test_task_under_cgroup__detach(skel);
>> +
>> +    ASSERT_NEQ(skel->bss->remote_pid, skel->rodata->local_pid,
>> +           "test task_under_cgroup");
>> +
>> +cleanup:
>> +    if (foo >= 0)
> 
> "if (foo >= 0)" is not needed. 'foo' is guaranteed ">= 0" as this point.
> 

Yes

>> +        close(foo);
>> +
>> +    test_task_under_cgroup__destroy(skel);
>> +}
>> diff --git 
>> a/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c 
>> b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
>> new file mode 100644
>> index 000000000000..5bcb726d6d0a
>> --- /dev/null
>> +++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
>> @@ -0,0 +1,51 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/* Copyright (c) 2023 Bytedance */
>> +
>> +#include <vmlinux.h>
>> +#include <bpf/bpf_tracing.h>
>> +#include <bpf/bpf_helpers.h>
>> +
>> +#include "bpf_misc.h"
>> +
>> +struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
>> +long bpf_task_under_cgroup(struct task_struct *task, struct cgroup 
>> *ancestor) __ksym;
>> +void bpf_cgroup_release(struct cgroup *p) __ksym;
>> +struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;
>> +void bpf_task_release(struct task_struct *p) __ksym;
>> +
>> +const volatile int local_pid;
>> +const volatile long cgid;
> 
> cgid cannot be a negative number. So let us do
> const volatile __u64 cgid;
> 

Ok

>> +int remote_pid;
>> +
>> +SEC("tp_btf/task_newtask")
>> +int BPF_PROG(handle__task_newtask, struct task_struct *task, u64 
>> clone_flags)
>> +{
>> +    struct cgroup *cgrp = NULL;
>> +    struct task_struct *acquired = NULL;
> 
> "acquired = NULL" is not needed. Just do "struct task_struct *acquired;".
> 

Ok

>> +
>> +    if (local_pid != (bpf_get_current_pid_tgid() >> 32))
>> +        return 0;
>> +
>> +    acquired = bpf_task_acquire(task);
>> +    if (!acquired)
>> +        return 0;
>> +
>> +    if (local_pid == acquired->tgid)
>> +        goto out;
>> +
>> +    cgrp = bpf_cgroup_from_id(cgid);
>> +    if (!cgrp)
>> +        goto out;
>> +
>> +    if (bpf_task_under_cgroup(acquired, cgrp))
>> +        remote_pid = acquired->tgid;
>> +
>> +out:
>> +    if (acquired)
>> +        bpf_task_release(acquired);
>> +    if (cgrp)
>> +        bpf_cgroup_release(cgrp);
>> +    return 0;
>> +}
>> +
>> +char _license[] SEC("license") = "GPL";
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/DENYLIST.s390x b/tools/testing/selftests/bpf/DENYLIST.s390x
index c7463f3ec3c0..5061d9e24c16 100644
--- a/tools/testing/selftests/bpf/DENYLIST.s390x
+++ b/tools/testing/selftests/bpf/DENYLIST.s390x
@@ -26,3 +26,4 @@  user_ringbuf                             # failed to find kernel BTF type ID of
 verif_stats                              # trace_vprintk__open_and_load unexpected error: -9                           (?)
 xdp_bonding                              # failed to auto-attach program 'trace_on_entry': -524                        (trampoline)
 xdp_metadata                             # JIT does not support calling kernel function                                (kfunc)
+test_task_under_cgroup                   # JIT does not support calling kernel function                                (kfunc)
diff --git a/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
new file mode 100644
index 000000000000..5e79dff86dec
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/task_under_cgroup.c
@@ -0,0 +1,55 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Bytedance */
+
+#include <sys/syscall.h>
+#include <test_progs.h>
+#include <cgroup_helpers.h>
+#include "test_task_under_cgroup.skel.h"
+
+#define FOO	"/foo"
+
+void test_task_under_cgroup(void)
+{
+	struct test_task_under_cgroup *skel;
+	int ret, foo = -1;
+	pid_t pid;
+
+	foo = test__join_cgroup(FOO);
+	if (!ASSERT_OK(foo < 0, "cgroup_join_foo"))
+		return;
+
+	skel = test_task_under_cgroup__open();
+	if (!ASSERT_OK_PTR(skel, "test_task_under_cgroup__open"))
+		goto cleanup;
+
+	skel->rodata->local_pid = getpid();
+	skel->bss->remote_pid = getpid();
+	skel->rodata->cgid = get_cgroup_id(FOO);
+
+	ret = test_task_under_cgroup__load(skel);
+	if (!ASSERT_OK(ret, "test_task_under_cgroup__load"))
+		goto cleanup;
+
+	ret = test_task_under_cgroup__attach(skel);
+	if (!ASSERT_OK(ret, "test_task_under_cgroup__attach"))
+		goto cleanup;
+
+	pid = fork();
+	if (pid == 0)
+		exit(0);
+	else if (pid == -1)
+		printf("Couldn't fork process!\n");
+
+	wait(NULL);
+
+	test_task_under_cgroup__detach(skel);
+
+	ASSERT_NEQ(skel->bss->remote_pid, skel->rodata->local_pid,
+		   "test task_under_cgroup");
+
+cleanup:
+	if (foo >= 0)
+		close(foo);
+
+	test_task_under_cgroup__destroy(skel);
+}
diff --git a/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
new file mode 100644
index 000000000000..5bcb726d6d0a
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/test_task_under_cgroup.c
@@ -0,0 +1,51 @@ 
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2023 Bytedance */
+
+#include <vmlinux.h>
+#include <bpf/bpf_tracing.h>
+#include <bpf/bpf_helpers.h>
+
+#include "bpf_misc.h"
+
+struct cgroup *bpf_cgroup_from_id(u64 cgid) __ksym;
+long bpf_task_under_cgroup(struct task_struct *task, struct cgroup *ancestor) __ksym;
+void bpf_cgroup_release(struct cgroup *p) __ksym;
+struct task_struct *bpf_task_acquire(struct task_struct *p) __ksym;
+void bpf_task_release(struct task_struct *p) __ksym;
+
+const volatile int local_pid;
+const volatile long cgid;
+int remote_pid;
+
+SEC("tp_btf/task_newtask")
+int BPF_PROG(handle__task_newtask, struct task_struct *task, u64 clone_flags)
+{
+	struct cgroup *cgrp = NULL;
+	struct task_struct *acquired = NULL;
+
+	if (local_pid != (bpf_get_current_pid_tgid() >> 32))
+		return 0;
+
+	acquired = bpf_task_acquire(task);
+	if (!acquired)
+		return 0;
+
+	if (local_pid == acquired->tgid)
+		goto out;
+
+	cgrp = bpf_cgroup_from_id(cgid);
+	if (!cgrp)
+		goto out;
+
+	if (bpf_task_under_cgroup(acquired, cgrp))
+		remote_pid = acquired->tgid;
+
+out:
+	if (acquired)
+		bpf_task_release(acquired);
+	if (cgrp)
+		bpf_cgroup_release(cgrp);
+	return 0;
+}
+
+char _license[] SEC("license") = "GPL";